Thursday 31 October 2013

Swanning around Salcey

Yesterday I got a Late Pass; ladysolly would be bridging all evening, so I could come home late. I decided to go to Salcey Forest to have a go at the Halloween caches recently set there.

I parked at the free car park there (where else?) and got the bike out. I started off with battery number 6, which gave me 13.8 kilometers and 6.5 amp-hours (it's supposed to be 10, so it's deteriorated somewhat).

The first cache I did, was one I've done before, but I hadn't got the code number from it. It was actually at the car park, and I found it immediately, but it's on a length of nylon line, and I could not get the container out. I pulled the line pretty hard, but I didn't want to break it, so eventually, I left it be.

My objective today was to get all the caches south of the east-west road that cuts across the forest, and, hopefully, some of the ones to the north.

So I set off along the track. The tracks in Salcey Forest are a mixture of excellently surfaced bike tracks, and horribly squishy muddy paths. It soon became clear that most, or nearly all of the fun "scary" caches had been replaced by micros, which I thought was a shame, because it wasn't even Halloween yet! And that also meant that some of the clues were no longer relevant. Never mind. After doing a few caches, I found myself at the site of "invisible man", where there was also a family of two adults, two small witches and a teenager were building a sort of dwelling out of the branches lying aruond here. That made me worried that maybe the cache had been disturbed, so after searching for 20 minutes, I gave up. But later on I met up with two cachers who had done that cache, and they described to me where it was, so I went back and got it.

One of the tracks was so muddy that in dragging the bike through the thick mud I stepped in mud that was deeper than my boots, so I got a slightly wet foot. And speaking of boots, the Hi-tec Euroboots I got from Amazon have been very good; comfortable and waterproof, but one of the tags where the lace pulls the boot close to the foot, has broken. I might be able to repair it, but in case I can't, I went on to Amazon and bought another pair for £45. And, while in a purchasing mood, I've noticed that some of my underpants are not fit for purpose (and some not even fit to be used as cleaning rags) any more, so I went on to Sportsdirect and got ten pair.

It was 3 pm by the time I'd finished the south part of the forest (including some at Hartwell) and got back to the car, where I had lunch, changed the used-up battery #6 for a freshly charged battery #7 (which gave me about 8 amp-hours before it died). Then I went and picked up the Invisible Man that I'd failed on before, and then north.

I was very pleased to be able to get a Salcey Trail cache that I'd DNFd when I went to look for it a couple of years ago, and then I found another in that series. But by then it was fully dark, and I was on my head torch. But after I found that cache .. well, it took me about two minutes to locate the cache, and then another 20 minutes to find my bike. In the dark, I'd got confused about which way was what. I do have something that is supposed to help me with this - a flashing red light to hang on a tree that I can see from a distance. But I hadn't used it.

I also visited the Piddington Oak, which is long dead, but impressively big. I saluted it in the appropriate manner. Or possibly in an inappropriate manner.

I got back to the road a mile or so away from the car. I have a good headlight, but it was at that point that I discovered that my rear red light wasn't working. So I gave my rear reflector a clean, and told myself that there wasn't much traffic, I'd be OK. In future, I'm taking a spare.

I got home at nineish, spent about half an hour in my post-caching routine (mostly that was spent in power-cleaning the bike, which was heavily caked with mud), then had to cold collation that ladysolly had left for me.

49 caches done and a couple of DNFs, and a great day out.

Wednesday 30 October 2013

Monday 28 October 2013

Bike maintenance

A few days ago, there was a horrible clanking and graunching coming from my front wheel. I stopped and had a look, expecting to find a stick caught in the wheel, or something like that. No, not a stick, it was a piece of wire. And on closed examination, I saw that it was one of my spokes!

A bike wheel has 36 spokes, but in my experience, it will work just as well with quite a few of them missing. But that isn't to say that you should run like that - it does weaken the wheel.

So when I got home, I measured the length of the spoke. Because it's an electric bike, the spokes are shorter than standard, on accound of the motor having a much greater diameter than an ordinary bike hub. I got onto Ebay, and it looked like 195mm spokes were what I wanted, so I ordered ten of them for a pound or two. I thought, maybe I really want 192 mm, but if that's the case, I'll re-order and brace myself to the loss of a pound.

Today the spokes arrived, so let's get down to it.

First I gave the bike a power wash; it needed it, after going through so much Arundel mud, and it's nicer to work on a clean bike. Then I upended it, and levered off the front tire, pulled the inner tube aside and removed the broken spoke. Putting the replacement in was a doddle, and I tightened it up so that it pinged to the same note as the others. Replacing the inner tube was easy because I hadn't fully removed it, likewise the tire, and then I pumped it up.

I noticed that the chain was looking a bit rusty, so I gave that a dose of bike oil, and by the time I'd done that, the front tire was deflated.


First I examined the outer of the tire, and I found five thorns embedded in it; one of these was quite long, about half an inch; another was short but must have been penetrating the inner tube because when I pulled it out, I heard "hissssss".

These days, I don't patch inner tubes. Because I'm getting the "thorn-resistant" ones so cheaply (£1.75), I reckon it's better to replace than repair. Also, I noticed that I hadn't put the gel insert into the tire. That's about 1/4 inch thick and it really toughens the tire up, because any thorn that penetrated the tire, will also have to penetrate the gel before it even gets to the inner tube. Punctures? Not for me, thanks.

So I put a gel liner into the tire, then a new inner tube, then I used my thumbs to push everything back in place. That needs strong thumbs, but if you can do it that way, you're much less likely to cause a puncture while you're replacing the tire.

While I had the bike upended, I had a look at the front brake pads. I mostly use my back brakes (you're less likely to go into a catastrophic skid) but I do use the front brakes when I need a bit of extra braking, such as when going downhill. They looked like they could be OK for a while yet, but I decided to replace them anyway; brake pads are only about £1, and a brake that isn't working as well as it could be, can be a *lot* more expensive!

Then I checked that the wheels ran free, and the back wheel didn't. On examination, I found that the kickstand was fouling the tire, and if left like that would not merely slow me down, it would cut through the tire, eventually. So, a bit of bike oil and a quick grip in the bench vice to make it work properly, and when I put it back on the bike it was fine.

So, we're ready for the next outing, which I'm thinking will be Wednesday, because I'm still seeing lots of rain.

Ruby wedding

Today, ladysolly and I celebrate 40 years of marriage. I got a penguin card from her, she got a birthday card from me, suitably edited. And I've got her an airprint-capable laser printer, so she can print from her iPads and iPhone.

Not much happened with the storm; a tree in next door's garden has lost a lot of its branches.

Sunday 27 October 2013

Petrol and electricity

I was thinking about how the Lipo batteries that I'm using, compare with petrol. After a bit of googling and calculation, I came to:

1 kg of Lipo battery, fully charged = 150 watt-hours
1 kg of petrol, converted into power by an internal combustion engine = 3000 watt-hours

So that's why petrol is a more portable store of energy than a battery.

Another thought - how long does it take to charge a Lipo battery? The ones I'm using are 5 aH and 4s. That means they'll give you five amps at 14 volts for an hour. For discharing, they're rated at 20C. That means that you can get that energy out in three minutes, if you wanted to, by drawing 100 amps from it.
For charging, they're rated at 5C. That means that you can charge it in 12 minutes, by giving it 25 amps at 14 volts.

When I have four batteries to charge, I can charge them in parallel. So if I can supply 100 amps at 14 volts, I can charge all four in 12 minutes. My power supply isn't able to deliver so much current, but if I wanted to, I could build one that would do it.

So, if you have an electric car made from batteries like this, how fast could you charge it? If the charger could supply enough current ... 12 minutes. Which is about how long it takes me each time I fill up with petrol, including the wait for the pump, and the payment.

One of the argumants against electric cars just curled up and died - they don't have to take a long time to recharge.

But isn't it dangerous to have so much current flowing? No. Now if you have 100 volts, that would be dangerous. But 14 volts isn't dangerous, because if you put a finger on the positive and a finger on the negative, very little current would flow. Even though the charger is able to supply 100 amps, the ohmic resistance of your body would mean that only a tiny current would flow. And 14 volts isn't something you'd even feel. And that means that you don't have to take the kind of careful precaustions that you have to take with handling petrol. Which means that outlets for charging could be all over the place.

I was talking to some folks at the Worthing bridge orgy yesterday, and I made three technology forecasts for the near future.

1) Self-driving cars. I really really want one, and even more, I really really want everyone else to be in one. Self-driving cars will *not* tailgate, will *not* change lanes without checking that it's clear. The death rate from cars would plummet, and it's worth it for that alone. The biggest obstacle right now, I think, is, when there's an accident, who's to blame? The human occupant, the car manufaturer, the software writer? As soon as that is sorted out, I expect to see a huge number of cars offering a self-drive option.

2) Lighting using LEDs. Incandescents are very wasteful, 90% of the power is lost as heat. Fluorescents flicker, and the low-energy bulbs in some of our rooms, take so long to come to full brightness,  I lose patience! But LEDs are very economical to run, don't flicker and come to full brightness immediately. The main obstacle is cost, but this is semiconductor technology, and we all know what happens with costs.

3) Electric cars. See my discussion above.

Bridge at Worthing

Ladysolly went to Worthing this weekend, for an orgy of bridge. Last time she had a bridge orgy, I was put into kennels, but this time she let me tag along. I went out caching while she riffled the Devil's Pasteboards.

The day we arrived, we had dinner early. Conversation was mostly about bridge, so I read a book. After dinner, I went out to Lancing and went round on the bike, picking up 12 caches (one was nearly a DNF, but I had another look, and there is was).

On Saturday at breakfast, the conversation was mostly about bridge, so I read a book. Then I went out to Amberly, and did a circuit of about 30 caches, all found. Then a solved puzzle, and then a few drive-bys. That got me back to the hotel in time for dinner. Conversation was mostly about bridge, so I read a book.

On the Sunday, I went to Arundel and did a 17-sized circuit. At one point, I lifted the bike over an electrified fence, and got a nasty shock. Then I realised that I didn't need to get over that fence, I was going off in a different direction. Grrr. At lunch, you can probably guess what the conversation was about, and my reaction.

So, a total of 80 caches over the weekend, and a lot of fun. I got very muddy, and I got soaked on each day by sudden heavy rainfall, plus lot;s of drizzle to keep me moist.

I used my wattmeter on one of the older batteries, number 8. That told me that I got 7.5 Ah out of it when running it down to empty, and it's supposed to be 10 Ah. Either the battery doesn't have the puissance it claims, or else it's got old very quickly.

They get some heavy floods around here!

I found this chap while doing a cache near a phone box.

Thursday 24 October 2013

A pension

You know you're getting older when you have to fill in the online form to claim your government pension

I don't feel like I've done anything to deserve it. OK, I've been doing useful work since I was 20 - or at least, people thought it was sufficiently useful to chuck money at me for doing it. And I assume that the major chunk that the government took in taxation (some of which they pretend isn't tax, they call it "national Insurance") means that I'm getting back a small part of what I put in.

But I still don't feel I deserve it.

Apparently, I could be getting up to £110.15 per week. Of course, I'll have to pay ta on that - the state gives, the state takes away. I'll probably only see £60 of that. And if I were to dare to spend it, the state would grab another 20% in VAT. And if I spend that on a tankful of petrol (not that you can fill a tank for £60), the government takes over half in duty (another word for tax, they are so creative in calling tax by other names).

So, all in all, I'll be lucky if I see a pony.

Speech synthesis

I want something to tell me when the number of alerts that my various systems have emailed to me is getting large. I already use the pilite for this; the normal scrolling display is interrupted with a display telling me there's a lot of alert messages. But I might not notice that.

Now I've put up a voice alert. When there's more than 100 messages in the alerts folder, a Raspberry Pi (connected to a speaker) says "There are 100 messages in the alerts" (or whatever the number is). This is the Pi that also drives my scrolling display of time and outside temperature, and whose main job is to run loads of terminals onto various servers.

I did this very simply. I plugged a speaker into the Pi's audio port, and I have a program that loops and looks at the count of messages. When it's more than 100, it does:

espeak -ven+f3 -k5 -s150 -a 1000 "There are $alerts messages in the alerts"

where $alerts is the count of alerts.

There's tons of voices to choose from, including "Ancient greek". Most of the English ones sound pretty much the same to me. The speech synthesis isn't quite Churchillian, but it's easily good enough for this purpose.

More buying problems

I bought a "IMax B6 Digital LCD RC Lipo/Li-ion/LiFe Battery Balance Charger imaxb6 80W & 50W" via Ebay. What arrived, was a weighing balance, for weighing very small weights, such as jewellery. But it took me a while to work out what had happened. All I knew at first, was that this little scale had arrived, and I was pretty sure I hadn't ordered it. It took me a while to work out who it had come from, because the package didn't have an invoice, or a sales slip, or anything that told me who had sent it. I had to go on Ebay and look at the several things I've bought recently that haven't arrived yet, and see which of them also sold a "0.001g 20g Digital Jewelry Gram Gem Precision Scale Weigh Mini Electronic Blance".

I suspect the word "balance" is what confused someone.

So then I opened a dispute with them, asking for a full refund. If they want me to send the item back, I will, but I doubt if it's worth the cost of the postage.

I'll give them a few days, as per Ebay's rules, after which I have to escalate the issue to Ebay.

Meanwhile, I'm sending the wrong stuff that Hobbyking sent me back to them, then they'll give me a refund or a credit note, I don't know which, then I'll have to put in the order again, except that the UK warehouse has run out of the batteries that I'm after, and no-one knows when they'll be in stock again. Oh well, I can buy them from the Netherlands warehouse at a slightly higher price and slightly higher shipping cost.

Some good news - the wattmeter I ordered has arrived, and I've soldered it to a pair of kettle plugs. Now when I use the bike, I can put that between the battery and the controller, and it'll tell me how many amp-hours have flowed. I'll have an accurate figure for the capacity of each battery.

I also received the "universal" chain guard to replace the broken one on the bike. It wasn't quite universal, I had to insert an extra spacer washer to make it fit properly, and I'm not sure how good it's going to be; it seemed to be not really tough enough. I'll see.

And a tool to remove the gears and freewheel from a back wheel. That will probably be useful in future - I've already had to replace that unit twice (it's the freewheel that goes), and I've been paying my local bike shop to do the job. But now I can do it myself, and I even have a spare set, from the wheel that's gone out of true when I hit the tree.

By the way, my head has pretty much healed up now. I can't see anything because of all the hair, but now I can press on the area without it hurting, so it must be healing up fine.

Tomorrow, we go to Worthing for the weekend. Ladysolly is attending a Bridge Tournament there, so I'll be caching around that area. Or possibly lurking indoors wishing it would stop raining.

Wednesday 23 October 2013

Cambridgeshire again

Last time I went up to Whaddon in Cambridgeshire, I did 50-odd caches, but that left plenty more to do. So today, I went there again to finish the area.

First, I did a puzzle cache. Solvng it was a three stage process. I got the first stage immediately, the second stage came out after a bit of crunching, but that left me with two large numbers and no idea how to turn them into coords. After bashing my head on it for a while, I emailed the Cache Owner, who gave me some help which didn't do me any good.

But this morning, I had an idea, tried it, and it worked. So I was able to go collect the cache, and after putting so much effort into solving the puzzle, you bet I wanted the cache!

I parked in someone's industrial area (there were other cars there, so I didn't think anyone would notice) and walked to GZ, where I spent several minutes getting prickled before I finally looked properly in the most obvious place, and there it was!

Then on to the first circuit of the day. That started in Meldreth, then went north, on the bike. I was trying out my idea of using the batteries in pairs rather than in fours, and it worked well. I got 9 km out of each pair.

After the first dozen caches, I'd planned to go on a track across country, but when I looked, it was the dreaded ploughed field with loose earth, and that's anathema to bikes. So I stayed on the road instead, I though, OK, I won't do the five that are along there. But as I proceeded north along the road, I saw a way I could cut west to the track I'd wanted to be on, and it was all on grass! So I took that, and was able to collect the five that I'd given up on.

I crossed the meridian a several times today. And there's proof!

So I did 25 caches, and it was 2pm, I was biking back to the car, and I got caught in a downpour. I got soaked. All over.

This looks like it's still in use.

Back in the car, I consoled myself with hot coffee and lunch, and thought about giving up for the day and going home. But the sun came out, I put on a dry coat and gloves, and did another small circuit of 11. Again, at one point I was faced with a ploughed field which NO WAY would I even try to cross wheeling the bike, but I was able to find an indirect route that got me around it.

Back to the car again, and another battery change. Then off to Shepreth, to do the Shepreth Saunter, or at least as much of it as I had time for, which turned out to be all of it! So I wound up with 73 caches done today, and no DNFs. A very good day out.

Grrr HobbyKing

I ordered 8 more batteries, a charger and some other stuff from HobbyKing. What arrived a couple of days later was a motor and an SBEC.

They sent me someone else's order.

So I contacted them to get this sorted out. It took them 15 hours to respond to the message I sent them; this is because they have a customer service disaster going on. What happened, is they've been sending Lipo batteries by air from Hong Kong and they've been told that they can't do that any more. And a large number of their orders included those, so sorting out that mess is consuming all their customer service resources. My stuff is coming from the UK, so isn't affected, but I'm caught up in the overall customer service resource bottleneck.

Eventually, I got a reply. I have to send the wrong goods back to them (fair enough), they'll then give me either a refund or a credit note, and I'll need to place my order again. I'm guessing it'll be at least a couple of weeks before I see the stuff.

Oh well.

Weight report 68

15 stone, 5 1/2 pounds

Tuesday 22 October 2013

How to make a really cheap electric bike.

How to make a really cheap electric bike.

Before you start, you need to be able to use a soldering iron, and bike spanners. If you
can't, then go learn.

You must also learn about the care of Lipos. They are dangerous, no question. I'd say that
each of the Lipos that I'm using is as dangerous as a pint of petrol. Which means that if you
don't do anything stupid, you'll probably be OK. But some people do treat petrol stupidly, and
get hurt. Likewise Lipos. So, learn about the safe handling of Lipos.

The two most important things for safety; 1) don't over-charge them (your charger should ensure that doesn't happen), 2) don't short circuit them by connecting a battery's positive to its negative (I designed my connectors to make that pretty much impossible). And I'd add a third, important not for safety but for keeping the batteries working,  3) don't let the voltage of any cell fall below 3.0 volts (I use 3.2 volts as a minimum).

First, you need a bike. If you're reading this, you probably already have a bike and you can
convert that. If you haven't got a bike, or don't want to mess with the fine machine that you
already have, you'll need to buy a bike.

I just checked Ebay; second hand bikes go for £20 and upwards. You'll want one with gears;
three at the pedals and five or more at the rear. You might want suspension; that will cost
extra. You might pay as much as £50 for a really good second-hand bike. You might need to
replace the brake pads (about £1 per pair).

You'll need a back rack. Not a "seat post rack", you want one that will be carrying the weight
of the batteries. That will be £11 or so. You'll also need at least one pannier, the kind that
hangs down from the back rack. £8.

That's the bike hardware, total cost £39.

Now you need the motor. Ebay again. This will probably come from China, and will probably be shipped by sea, unless you want to pay a fair bit extra for airmail. Here's what the wheel looks like, after I put on an inner tube and a tire, and installed it in the bike.

The wheel should come with cables and a small controller box. I mount that box on the back rack, as you can see here. Then I wrap the protruding cables in duct tape, to improved the water and mud resistance.

Here you see the controller on the back rack, with a pannier hung from the rack.

The orange cable is a 13 amp household flex, taking the power from the controller to the motor, because the motor I had came with cables that were too short.                              Usually, the cables won't be too short.

You want a 250 watt motor, because that's what's legal in the UK. That can be 24 volts, 36 or
48, it doesn't much matter which. I see a 24, 36 and 48 volt 26 inch wheel on Ebay for £153,
including postage. This is the biggest cost, but for that you get the wheel, and also the
controller, headlights, a key switch, a throttle and some other stuff that you probably won't
use. Notice that the wheel is 26 inches; that's great if the bike you're converting is also 26
inches (26 inches is the commonest size). It's very bad if the bike has a different wheel
size. So, obviously, make sure you get a wheel the right size.

How much is 250 watts? It's about a third of a horse power. The average human who is fairly fit, can do 50 to 150 watts for an hour, but if you're looking at an 8 hour stint, 75 watts is about it. So you can reckon you're riding a third of a horse. Or you're being towed by three people.

Also, notice that there probably isn't a disc brake disc on the hub of the wheel you're
buying. That means that they bike you're converting, should have caliper brakes (i.e., not
disc brakes). If the wheel you're buying does have a disc for a disc brake, then you can have
a disc brake. I hope that's clear! One bike I converted had a disc front brake. No problem, I
installed a caliper brake there, and that works fine.

Should you get a front wheel or a back wheel? A front wheel is very easy to install. A back
wheel will come with gears (5 or 6) which you'll want to be the same number of gears as on the bike (and you'll probably need to adjust the gears after you've installed the wheel). The
advantage of having the motor on the back wheel, is that a lot more of your weight is on the
back wheel, so it'll grip better. But having said that, I've always used front wheel motors,
and I don't have a problem with grip. When you're needing to put in a lot of effort, you're
using your pedals and that always drives the back wheel. And I think that maybe having part of the motive force on the front wheel (the motor) and part of the motive force on the back wheel (me pedalling) means I have a two-wheel drive, which has some advantages over a one wheel drive.

24, 36 or 48 volts? I got 24 volts because I already had some 24 volt batteries. The advantage of 48 volts, is that with 24 volts the motor is pulling 10 amps (and can pull a bit more for short bursts). But with 48 volts, the same power (250 watts) pulls 5 amps. So you could use thinner wires. But you won't, because the wires that you get for mains electricity can carry 13 amps, so they'll work here too, and there's no real saving in using thinner wires..

Now you need a battery. It took me a long time to realise that I should go to the model
aircraft and car community, because that's by no means obvious, or at least it wasn't obvious to me. They runs models that are really powerful, with powerful motors and heavy-duty batteries. Hobbyking is the place to go. Everywhere else seems to be double their prices. I was very surprised about that.

Let's assume you got a 24 volt wheel. You might think that you want a 24 volt battery. But
it's not so simple.

Lithium batteries (Lipo) are 3.7 volts. So 3 in series is 11.1 volt, 6 in series is 22.2 volts
- not enough, you see? But. When fully charged, thay're 4.2 volts, so six of them are 25.2
volts. Which sounds like enough ... but it very quickly won't be.

I took one of my old 24 volt batteries apart, and it had seven cells. 29.6 volts when fully charged. So that's what I thought I wanted. But it's not so simple.

You can't get seven-cell batteries. Mostly what you can get, are 4 cell and 3 cell batteries (and less), so maybe you could put a 4-cell in series with a 3-cell?

I thought about this, and I thought about the possibilities for making mistakes, and I
thought, suppose I use two 4-cell batteries in series? That's a nominal 29.6 volts, and 33.6
volts when fully charged. Will the 24 volt equipment on the bike be able to handle this
highter voltage? I thought it would, and it did. So that's what I'm using; two 4-cell
batteries in series.

Hobbyking offer 5 Ah, four-cell Lipos (product ID T50004S-20HC) for £18.25, which is
blisteringly cheap. And if you leave the page loaded for a few minutes, a pop-up will offer
you a discount. I got 9% off. You'll need two of these; that will give you a 29.6 volt, 5Ah
battery pack. Most electric bikes that you buy, have twice this capacity. You can too; just
buy twice as many batteries. Or even more. I've bought 12 batteries. And if you bought a 36
volt motor, you would use three of these four-cell batteries in series. or with a 48 volt
motor, use four.

Here, you see two four-cell batteries taped together (the tape is just for handling convenience); I also tape a handle to them because I don't want to lift them by their wires, because if those wires break, I can't use the battery. I've soldered a female kettle plug to each of the batteries, because I'm using kettle plugs as my standard plug and socket. Radio Control folks wouldn't use those because they're big and bulky, but I like big and bulky for bike connectors. You can also see the small white connectors, those have wires that go to each cell inside the battery, so that the charger can charge each of the cells equally. What you see below, has a nominal voltage of 29.6 volts (33.6 fully charged) and 5 amp-hours. That would last me maybe 2 hours on the bike. Obviously how long it lasts depends on how much power you use; if you want to, you can do 90% of the work with pedalling and then the batteries might last all day. I like to use the battery a lot - that's what it's there for!

You'll also need a charger. You can't use any old battery charger for Lipos. At Hobbyking, the
ECO6 costs £13; that lets you charge up to six batteries at once. Here's my charger, I use an iMax 8. On the right, I've connected a wattmeter, costing £5, which tells me how much power is going into the batteries. The wattmeter is connected to  four male kettle plugs, so I can charge four batteries at once. You can also see the white plugs; they connect to the white plugs on the batteries, and they let the charger charge all the cells in each battery equally. The charger only has one balance port; you can see the six-way adaptor in this picture.

Here's another parallel power adaptor; that will let me charge six batteries at once.

And you need to power the charger. For that, you can use anything that gives 12 volts or
thereabouts, and enough amps for the charger; at least 5. I use an old PC power supply, zero
cost. If you buy a power supply from Hobbyking, that's £30. I use the 12 volt line (coloured yellow for positive, and the black is negative), of course, and that's connected to a couple of female 4mm connectors, which is what the 4mm male connectors of the charger want to mate with.

You'll also want a multiple balance lead so you can charge and balance up to six batteries at
once, £1.36. And you want a cell voltage alarm (PRODUCT ID: Voltage-Alarm) to tell you when any cell falls below 3.2 volts while you're riding the bike. One for each battery, so you need two, that's £5.32. I'd also suggest a car-type fuse, just for extra safety (£2, and I don't have a really good justification for including this, except that it costs very little and if anything goes wrong with the wiring while I'm out, I'm hoping that the fuse will blow rather than something more drastic happening), and a voltmeter to display on your handlebars (£1).
How can anything go wrong? Well, I've come off the bike a few times over the years; nothing too drastic, but that could damage things in an undefined way.

Get some 4mm connectors. 10 pair for £3.17, you'll need them for connecting to the batteries and the charger.


Bike           £20
Carrier        11
Pannier         8
Motor kit  153
Batteries     34    (5 Ah)
Charger      13
Misc             13   (leads and connectors)

Total           252

The cheapest electric bike you can get is more than twice that, and for a good one, you might
pay £1000. But this way, you get a base bike that's as good as you want it to be (suspension?
gears? brakes?) and as much battery as you want. I assumed 5 Ah above, but you probably want at least 10 Ah, and maybe more. If you buy six batteries, then you'll be able to charge them all at once (but see next paragraph).

If you've fully run down some of your batteries, but only partly run down others, then you
can't charge them all together, because as soon as you put them all in parallel, an immense
current will flow from the partially charged to the discharged, and that's not good - it could
even be quite bad. By "bad" I mean maybe catastrophic. So, charge the fully discharged ones,
then take those off the charger and charge the partially-discharged ones. Or get two chargers (that's what I've done).

So now, with all the parts acquired, it's time to build our bike.

First, install the wheel. That installs just like any bike wheel. Then you wire it up to the
controller; that's just a matter of plugging things together, and you can't get it wrong. The
controller will have some extra wires; there's wires to the replacement brake levers, so that
power is cut when you brake. I don't bother with that, because I can't actually brake unless I
take my thumb off the throttle. There might also be wires for a pedal sensor, which again I
don't use because I prefer to use a throttle. And maybe a cruise control - again, I prefer to
use the throttle.

If when you connect everything up, the wheel spins backwards, don't worry! You can either
install the wheel the other way round, or else you can change the three power connectors for
the wheel, so they connect in a different order. Instead of yellow-yellow green-green,
blue-blue, you might try yellow-green, green-blue, blue-yellow, for example.

The controller will also have wires that go to the battery. I connect those to a male kettle
plug, and I connect the batteries to a female. That makes it easy for me to disconnect the
battery pack completely, so I can take it off the bike quickly (very useful when I want to
lift the bike over an obstacle).

 There will also be a display to show you power, on the handlebar. I find those of limited use; it's just 1, 2 or 3 blobs, os something similar. And with the overvoltage we'll be using, it won't tell you anything useful. But a voltmeter is great. You wire it in parallel with the blobby-meter, and it tells you the voltage of your battery pack, which is a pretty good indicator of how much push you have left. Below, you can see the blobby-meter, looking very like a petrol gauge, but actually pretty useless, because I'm not using the voltage that it's expecting. Blu-tacked to the top, you can see the voltmeter, which gives me an accurate reading of the battery voltage. And when I apply power to the wheel, I can see how that voltage drops as the battery comes under load.

It starts at 33.6 volts (4.2 times 8), and when it gets to about 28, the batteries are nearly exhausted, and the cell alarms will start to go off soon.

On kettle plugs - on Ebay you can get 10 extension leads for £15 (search for "kettle plug
extension").  That gives you ten male and ten females, already wired up.  Cut the lead in the
middle, and solder the lead to whatever it need to be soldered to. I already had several dozen
of these doing nothing. These should be able to handle 13 amps, and you're putting 10 amps

The battery pack is wired up thus. You have two 4-cell batteries, wire them in series. Put the
car fuse in series with those. If you have a 250 watt motor, it should draw maybe 10 amps
(watts = amps times volts), so a 15 amp fuse (or maybe a 20) is what you want. I carry a few
spare fuses. And connect that to the female kettle (female, because you would have to be
trying really hard to short circuit a female kettle plug).

It looks like this.

+kettle _____ fuse _____+battery1   -battery 1_____ +battery 2    -battery 2 ___ - kettle
I call that the driver cable. It looks like this. You can see the car fuse poking out attached with the red wires. The two short cables go to two batteries, the long one goes to the controller.

But you can't use that for charging. For that, you put the batteries in parallel. I call that
the charger cable,

So  the + of battery 1 is connected to the + of battery 2 and the + of the charger.
And the - of battery 1 is connected to the -   of battery 2 and the -   of the charger.

When charging, you use the parallel balance lead cable to connect the balancing ports of the
batteries, to the balancing port of the charger When driving, you connect each of the
balancing ports of the batteries to a cell voltage alarm. I set mine to alarm at 3.2 volts.
The reason for this is that if you run a Lipo down below 3 volts, you can find that it won't
charge up again.

The throttle goes on the handlebar (I prefer the right). The controller goes on the back rack;
I just bolt it down, wrap the wires coming out in duct tape and splodge some sealant on the
tape to help it be more waterproof. The batteries will go in the pannier. I use cable ties to
make the various cables neat on the bike frame.

And here's what the completed bike looks like. The batteries (both charged and discharged) are in the pannier; if that doesn't give enough room, I put on the other pannier.

The bike is a bit heavier because of all this. The motor is pretty heavy, 2 or 3 kilograms. The batteries are about 1 kg per pair (giving 5 AH). So if you want 30 AH (which is about what I use in a full day's cycling) that's about 6 kg. That's a lot, but when you're trundling along, the bike is carrying it, and if I need to lift over an obstacle, I unplug one kettle plug, take the pannier off, lift the bike over, and replace. So it's pretty quick. And I rarely carry the full 30AH. Usually, I do a circuit in the morning winding up back at the car, then another in the afternoon. So while I'm back at the car, I can swap out exhausted batteries for full ones.
By the way, for comparison, a standard car battery holds about the same amount of power as these 6kg of Lipo batteries. And weighs about four times as much.

If you haven't got a bike helmet, then get one. I only have one head, and I need it. I always
wear gloves; I do come off my bike sometimes (I ride on rough ground) and gloves keep my hands usable. If you'll be riding at night, get a good head torch (which can also have a red
flashing light at the rear). And a bell, to warn pedestrians that you're coming through. I
also carry a good strong bike lock and some puncture repair and bike repair tools; since
you're already riding with a pannier, you have somewhere to keep this stuff.

Good luck with your new electric bike, and have fun!

Haywards Heath caching visit

I picked up the bike. The lady told me it had only been out three times; after they bought them, they decided that the area was too hilly for biking. So I got a Haro DX folding bike for £56, almost new condition (I can see from the tires it's hardly been used), a real bargain.

It was raining on my way there, but that became a light drizzle just before I arrived.

Then onwards to do some caching, by which time the rain had pretty much stopped. This was almost entirely on roads. The new battery pack again performed wonderfully, and I did 43 caches, two DNFs.

I discovered something good by accident. I've always been careful not to reverse the polarity when connecting the old batteries to the controller - it's easy to plug it in the wrong way round (which is why I'm using kettle plugs on my new battery packs, you can't get those the wrong way round). So today, I made the inevitable mistake - I connected it the wrong way round. Worst case was there's a flash and a bang and a dead controller. Best case was, nothing happens. And nothing happened. So I saw my mistake, plugged it in the right way round, and everything worked. Nice.

My order from Hobbyking arrived today. Or rather, someone else's order arrived. Right delivery number, completely wrong contents. Sigh. So now we'll have to sort this out.

Sunday 20 October 2013

Haywards Heath

Tomorrow, first to Haywards Heath to pick up the bicycle I got via Ebay. Then east from there to a series that runs north-south along roads. I'll start in the middle, go south and back, which will get me back to the car where I can have lunch and change the battery. Then north and back.

The weather forecast is for rain in the morning, clearing up in the afternoon. So I might get a bit wet.

The chain guard on bike.2 has cracked, so I've ordered a replacement from Ebay.

Pi stability

I set up a mail server using a raspberry Pi, last January. I have another server that pings it once per minute, to check that it's still running, and it emails me if it isn't. Another server power-cycles the Pi if it's been non-responsive for a few seconds.

That Pi has now been running non-stop for nine months; I just checked the "uptime" at 263 days.

If anyone thought that the Raspberry Pi wasn't stable enuogh for serious use, they're wrong. You do need a good power supply (I'm using an old PC power supply, with a step-down circuit to get the 12 volts down to 5.3).

Saturday 19 October 2013

With ladysolly to Hemel

We went out caching today, on foot. First a ring of seven puzzles that I solved last night, then a small series of rather tricky little caches, with a bonus. Then we just swanned about in the car picking up a few more. Just after we decided to stop and go home, it started raining hard. Good timing!

Bike bought

Hurrah, I bought the Haro folding bike via Ebay, and it was only £56. Now I have to arrange to collect it.

Pi problem

Not really a Pi problem. The Pi controlling the Robotic Arm stopped working; it wouldn't even boot up. On investigation, this turned out to be a failure of the SD card. Fortunately, I have an image of each Pi's SD card on another server as a backup. So I used that to create a replacement, and the Robotic Arm is operational again.

Hobbyking got back to me to tell me that I could only have the "buddy price" for three batteries, and I wanted eight. But by then, I'd worked out a way to get the eight at the price I'd paid for the original four, so they're ordered and will probably turn up some time next week.

I'm bidding on Ebay for another Haro folding bike. Because they really are very fine, and I'm hoping I can get another one for £60. It'll be good for spares, although I have a feeling that I might turn it into another electric bike :-)

Friday 18 October 2013

More batteries

I've had the new Turnigy batteries out on the bike twice now, and both times they've performed as I'd hoped. So I've just put in an order for eight more, which I'll make up in pairs to give four 5Ah, 29.6 volt battery packs. I've also ordered another charger, because one charger can only charge up to eight batteries, using the parallel adaptor I've just soldered up.

When you do parallel charging, the batteries that you're charging need to be at about the same voltage. If one is part-used at 3.9 volts, and another is fully used at 3.2 volts, as soon as you connect them in parallel for charging, huge currents will flow from the more charged to the less charged battery, and that's not good for the batteries.

So, I anticipate ending the day with a bunch of fully discharged batteries, and a pair of partially discharged ones. And that's why I need at least two chargers.

After I placed the order, I went down to the workshop and soldered up the eight-way parallel charger, and the adapters that I'm using so that the batteries each present a kettle plug as their main input/output. Doing that, finally used up the roll of solder that I inherited from my father, 60 years ago. This is Savbit multicore solder, and it's always worked well for me. Thanks, dad.

I have another tube of Savbit solder ready to go, and a spare on order.


I was in a park, trying to grab a cache. From the path, it was just the other side of a bush, so there I was sitting on the ground, writing in the log, and I couldn't help but overhear what was going on a few yards away.

I didn't really get the details, but it was a loud scream of "You hate me and I hate you, you never come to see my {something at school}, you always preferred {I'm guessing her sister}".

I was expecting a loud stream of swearing back, but no. {Presumably her mother} sounded calm and reasonable, and well-spoken. Followed by more screaming from the teenager.

As soon as I could, I got on my bike a pedalled away. None of my business. But I felt really sorry for the mother.

I had teenagers once.

Compulsory gardens.

What a good idea! And, like many good ideas, it can be made even better. 

Let's make geocaching compulsory - a legal requirement to find five-a-day. Have you done your five-a-day today? It's good exercise, and stimulates the mind.

Let's make programming compulsory - a legal requirement that everyone be provided with a Raspberry Pi and forced to write five programs each day. Have you written your five-a-day yet? It stretches the bain and keeps you alert.

Let's make bike riding compulsory. Everyone over the age of two should be provided with an age-appropriate bicycle (and helmet), and be required to ride five kilometers (not miles) per day. Have you ridden your five-a-day yet? It's good exercise and toughens you up each time you fall off.

Readers of this blog are invited to suggest further compulsory activities - even if all of these make it impossible to find the time to maintain their allottment.

Thursday 17 October 2013

Rollicking round Royston

Up North to Royston today; the weather looked good, so I went out caching.

First, 28 caches using one of my old batteries, then 38 caches using my new battery pack.

As I was going across a golf course, I saw this:

So a total of 66 caches done today, plus a few DNFs.

Wednesday 16 October 2013

New wheel

The replacement rear wheel that I ordered from Ebay arrived - but I don't need it. I had a look at the wheel with the wobbly axle, and it turned out that (I think) all it needed was the axle nut to be tightened up a fraction, so that the ball bearings aren't s loose in the ballrace. Never mind - I put the full monty onto it (tape to protect the inner tube from the spokes, gel insert to absorb thorns penetrating the tire, puncture-resistant inner tube and Kevlar-reinforced puncture-resistant tire), and it's ready to roll. And all that puncture-resist stuff really works. I've never had a puncture while out since using this.

I had an idea about bike batteries. I'm putting together four 5 AH 14.8 volt batteries to make a single 10Ah, 29.6 volt battery pack. But thinking about this, I made it into a 10Ah because that's what my existing batteries are. There's no reason why I shouldn't make two 5Ah, 29.6 volt battery packs out of the same batteries, and the advantage of that is that it gives me a bit more flexibility. So when I'm going out, I can take 3 of these 5Ah with me, and when I get back to the car after the morning's biking, maybe one is empty and one is half-used. So for the afternoon, I can take 3 full 5AH and the half-full 5Ah, for example. If I use them made up into 10Ah packs, I couldn't do that.

So I've made up a driver cable suitable for a 5Ah, 29.6 volt battery pack. I can use the same charger cable as before.

Tomorrow I'm planning to go north of Royston; there's a few circuits there that I'd like to tackle.

Weight report 67

15 stone 4 pounds.

Tuesday 15 October 2013

Cycling round Stevenage

I was keen to try out my new battery pack, and there's an "On yer bike" in Stevenage, so that's where I went.

The battery lasted for 36 caches, which makes me very happy. I was on my way to the 37th when the voltage alarms started ot go off, telling me "Stop using the battery". So I switched to one of my older style batteries, and finished on that. It looks like I'll be getting a bunch more of these, and I'd recommend them to any electric bike owner whose battery is more than a couple of years old, and is not as vimful as it used to be.

48 caches done, and a few DNFs.

While I was searching for a micro in ivy, a cyclist came up to me and asked me if I had a pump. He had a flat rear tire, so I loaned him my pump and that was enough to get him home. I didn't find the micro.

On the way there, I stopped at my local Tesco to pick up sandwiches for lunch. But their shelves were bare. So instead, at lunchtime, I relocated to a Sainsbury's car park and got hot chicken plus some bagels, which I ate in the car. Lovely!

Monday 14 October 2013

Out tomorrow

For the first time since I tangled with that tree, I'm going out. To Stevenage, where there's a couple of good bike trails. I'm planning to start off by using my new battery pack, and run it till it's empty (3.2 volts per cell). If that goes well, I'm thinking of buying enough to make two more packs.

Hobbyking have an interesting discount system. When I was on their web site before, if I stayed on a page for a while, it would pop up an offer of a 7% or so discount. It doesn't seem to do that now, even though I've deleted the cookies.

But they have another discount, the "buddy discount". With that, I can get 13% off, which is nice. But when I tried to use it to order eight batteries, it wouldn't allow it; it seemed to top out at three. And it wouldn't let me buy three at the buddy price and five at the full price. It isn't worth putting in three separate orders, because of carriage. So it looks like I'll be paying the full price, although even their full price is really really low.


 First, let me get one thing clear. Haggling is the act of getting a better price than the first offer; bartering is the act of swapping one good or service for another, without money changing hands. Some people use the word "barter" when they mean "haggle". I don't.

One of our family domain names came up for renewal. I asked ladysolly if we were still using it, and she was, so I have to renew it.

Network Solutions want £115.59, plus VAT = £138.71 for a five year renewal.  VAT? They're a US company. If I'm paying VAT, it should be to a VAT-registered company. Are they registered? I don't know.

So I had a look at Godaddy. They want £47.75 for five years if it were a new registration, but it isn't, it's a transfer, so that's £26.45. They say nothing about VAT. And, by the way, that tells me that they should be willing to go for £26.45 if it's a renewal. Noted for future reference.

Network Solutions did make me an emailed offer when they reminded me about the renewal, though.  The renewal would be cheaper if I renewed for only one year. But it's still £138.71 for a five year renewal. Plus VAT.

So I set the transfer in motion. It isn't easy, nor should it be! I had to unlock the domain name at Network Solutions and request a code. Then I had to tell Godaddy that I wanted to transfer, and paid them, and got a code from them. Then I waited three days and got the code from Network Solutions. Then I tried to use it, and got refused because I changed my fax number a few weeks ago. So I had to call tech support. They give the number as 1-888-642-0209, but from the UK (I found out after some googling) that's 001-888-642-020.

I got through to Howard. I asked him to remove the block, and he asked me why I was changing registrar. I told him "You're too expensive". He came back with an immediate offer of $9.99 per year, that's £31. A far cry from £115.59,

I told him that wasn't cheap enough. So he offered $8.99. I asked him if he could do $7.99, he asked his boss, and boss said yes. So now they're at $39.95 = £25, so I said, "OK then." Then he said "Plus VAT", which brings it up to £30.

So I said "No", because I felt that I was being treated like a muggins.

The fact is, the service that they provide is entirely automated. OK, they do need staff; programmers and support staff. But their marginal cost of providing this service is near-zero, and that's why A) they were so willing to come down from £138 to £30, and B) why they have competitors that are so much cheaper.

I've had this domain name for 15 years or so.  Loyal customers get rewarded with higher prices; that's standard in this world, it's called the "Loyalty premium". Unless they threaten to move, in which case they get offered more reasonable prices. Howard gave me a number to call in future because I have a few other domain names with them, that's 877 307 1435, and you probably put 01 in front it if, but I'm not sure. He says that will get me lower prices.

Wouldn't it be nice if they offered me those lower prices without me having to haggle? But it won't happen. So that's the message -  haggle. Ask for a lower price.

So when is it right to haggle? Not in Tesco, for example. But it's very much worth haggling if what you're buying has a very small cost to the vendor (as in this case) compared to the price they're asking. And if you can easily take your business elsewhere.

And how far can you go with the haggle? That's an art; you need to think about the cost to the vendor, the price from his competitors, and how important the last few pennies are to you, compared to the time you're spending in the haggle. Also, I don't bother giving detailed reasons for wanting a lower price.

I haggle because in such cases when I don't, I feel that I've been ripped off with my own connivance.

Sunday 13 October 2013

Battery test

I gave my new battery pack it's first proper test today - I don't count the test that was cut short when I hit the tree.

I wore my most solid crash helmet. And, by the way, I've ordered a full-head motorcycling helmet with face plate. You don't need to hit me over the head more than once for me to learn.

I tried the battery pack out on my three different electric bikes; one standard, one with a sensorless motor and one with the motor I got a few months ago from China. They all ran very well.

When I got the battery back, I noticed that one of the plug/sockets was rather loose, and that one pair had been used a lot more than the other (the batteries are two pair in parallel, each pair being in series to give me an 8-cell, 29.6 volt battery pack at 5 AH, and the two of those pairs in parallel making it up to 10 Ah). So I think I was running off only one of the pairs.

If that happens when I'm out, it's not a disaster. It means that one of the pairs will run down and start beeping while the other one is still charged. I'll be able to see that, as soon as I look at the battery pack, because each battery of four cells shows me its voltage, and the voltage of each cell. And what I'll do then, is disconnect the run-down cells, and run on the ones that hadn't been used.

Better, of course, will be to have good connections in the first place!

Since this worked out so well, I'm seriously thinking of getting more of these batteries; enough to make up two more packs. That's 8 batteries at £18.25 each, £146 to add 20 AH to my capacity, for a weight of about 4kg. I'm thinking that changing battery while in the field would take a bit longer than it does now; with my old batteries, I just have to unplug the old one and plug in the new. With my battery pack, I have to unplug the main lead, then unplug the four power leads to the batteries, then unplug the four charge monitors. Then plug all that lot back in with the new battery. Even so, I can't see it taking more than a minute or so, and the way I've designed it, I can't plug anything in the wrong way round. And with the old batteries on the bracket they used to be on, it could take me quite a few minutes to lever the old battery off and ram the new one in; with the new battery packs simply sitting in a pannier, that's no longer relevant.

Another useful purchase would be a large ammo can; they're used a lot in caching as good, strong, watertight containers. One of those would nicely store three of my battery packs, and keep them safe from damage while in transit.

Something that occurs to me for possible future use - previously, I was committed to 24 volt batteries, and if I moved to a 36 or 48 volt motor, those batteries would be wasted. But now, if I want to change to a 36 or 48 volt motor, all I have to do is a bit of reconfiguring; for example, for driving a 36 volt motor, I would make my battery pack out of six of these batteries instead of four. So it's just a different wiring harness!

Strangeness in the credit card system

Something strange has happened to the credit card system, and I can't think what the cause might be.

From the 8th October, the number of credit card declines that I'm getting, has roughly doubled.

You get a decline when there isn't enough money in the card you're trying to bill, or if you got the expiry date wrong, or if the bank just feels like declining it. That last category includes:

Bank is worried about the billing coming from a foreign country
Bank is concerned that the billing is far from the usual pattern of spending
Bank just declines one in twenty billings, just to show they care.
Bank declines the billing for no reason that anyone can discover

I don't know what's caused this recent increase in declines.

Dismuke and xfe

I've been using Dolphon as my file manager, but it's very heavyweight and a little clumsy to use, I feel. So I had a look around and found xfe, which is advertised as being very like Windows Explorer, which is one of the best products from Microsoft (their optical mouse is the best). And that's what I'm using now.

Dismuke is something I found some years ago; it's a site devoted to music of the 1940s and before. I haven't visited it for a long time, and I went back there today. It's alive and kicking, and I'm currently listening to Radio Dismuke, available via TuneIn Radio on my iPhone. Lovely.

Saturday 12 October 2013

Reading winmail.dat

A supplier just emailed me with an "invoice enclosed". The file he sent me was winmail.dat.

It I were running the same mailer that he's using, there would probably be no problem. But I'm not using Microsot Outlook. So how to I read this file?

"yum install tnef" installed a program called, tnef, then "tnef winmail.dat" extracted a pdf file, which I was able to load into Acrobat Reader, and print out

I wonder how their other customers cope. Maybe they all use Outlook.

Anyway - the Anderson Powerpole 30 amp connectors just arrived, and I have to say, they're very neat. They can handle 30 amps, they seem to be easy to connect a wire to, and you can make up a N-way connector for whatever value of N you please, by making them interlock. The batteries I bought seem to be working out so well, I'm thinking of getting another set, and I might well use these connectors instead of the kettle plugs, because they are so much smaller and neater.


I had an inspired thought, and I've soldered up two new "foolproof" wiring harnesses. One for charging, and one for driving.

The "foolproof" aspect happens as follows. If, with a lead-acid car battery, you connect the positive to the negative, you get a flash and a bang as hundreds of amps make their way across, and much damage is done. A Lipo is ten times worse. These batteries are as dangerous as a can of petrol. Meaning, if you treat them right, you won't have a problem, but if you do something foolish, you can have a very big problem.

So I've used kettle plugs (IEC 60320) connectors. Female to the battery, because with a female kettle plug, it's pretty much impossible to cause a short unless you really try hard, so the batteries get the females. The male plugs are pretty easy to short if you drop a bit of metal into the plug, so the males will be on the other end, where there isn't any power until the male is plugged into the female, and therefore safe.

And then for charging, four males to a pair of bananas (which is a lovely phrase). The bananas plug into a watt meter (which tells me the number of amp-hours charged), that plugs into the iMax charger, which plugs into a PC power supply, which is connected to the mains electricity.

For driving the bike, four males to a female (which also is a lovely phrase) via a fuse set to blow at 25 amps, because if 25 amps is coming out of the battery pack, something's gone very wrong, the maximum should be 20 amps, I think. And the four batteries are each connected to an alarm that sounds off if the voltage of any cell falls below 3.2 volts, so that I know to stop using the battery.

I also wired up a digital voltmeter at the front of the bike, so I know the voltage of the battery pack, which starts at 33.6 and if all the cells fall to 3,2, then that will show 25.6, So between 33.6 (full) and 25.6 (empty), I know how much power I have left, roughly. That uses green LEDs, because I found that the red LEDs are impossible to read in bright sunlight.

I've ordered another wattmeter, that will go on the driving wiring harness, so I'll be able to see how much power I've used at the end of the day (or when a battery is about to be changed).

Friday 11 October 2013

New helmet

My encounter with the tree in my back garden has reaffirmed to me the value of wearing a helmet while biking. Which, of course, I always do ... except in my back garden.

On Wednesday, while I was out, I was hit in the face by a flying insect which then gave me a very nasty sting; my face is still swollen from it. And I can't count the number of times I've gotten a flying insect in my mouth. Plus getting rain on my glasses means that my vision is very blurred. So I had a think.

And went on to Ebay, where I found a full-face helmet with visor, intended for use with motorcycles, but I'm not picky.   £33 has bought me some serious head and face protection. It might be a bit over-warm in summer, but that's a problem for several months time.

And I bent the bike

I had a look at the bike I just crashed into the tree. Somehow, I've managed to distort the rear wheel and the spindle. It doesn't look like it the sort of thing that's easily fixable, so I've ordered a new rear wheel, with 7-gear freewheel, from Ebay - £25.

Thursday 10 October 2013


I've soldered up the wiring harness and fuse for the Hobbyking #1 battery, it comes to 2.3 kilograms; that's incuding the heavy-duty (4 sq mm) cable I'm using. The batteries I've been using are 3.1kg, so that's a nice bonus that I wasn't originally planning for.

So then I got my bike out, fixed the back brakes which needed new pads, and a couple of other minor things. And then I got bike.1 out - that's the one with the new wheel motor from China. I put  checked that the polarity of the new battery was correct, I checked that the voltage was what I expected (33.6), and plugged it in. Nothing happened. So I turned the key in the ignition. Nothing happened. So I checked the battery again, it was OK. Then I remembered, I put an extra switch on that bike so I could switch the battery off without having to stop and mess about with the pannier. So I switched that on, turned the key, and the power lights came on! Hurrah. And when I lifted up the front wheel, and gave it a bit of throttle, it spun. So, it looks like the controller can handle the slight (15%) overvoltage that I'm giving it, and the bike motor doesn't mind either.

So I took the bike out of the garage, and took it for a ride around the back garden. It worked well, and even when I gave it full throttle, nothing cut out (with the batteries I already had, it was cutting out on full throttle). So I took another turn around the garden, and then another at full speed, and then another, and as I was going round I looked down at the bike controls for a second, and when I looked up, the tree in the middle of my back garden was about six feet away and getting closer at a rate of, I estimate, 20 feet per second (because I was doing about 15 mph). I had just enough time to think "Oops" and to try to swerve, but not enough time. Actually, the word I thought wasn't "Oops".

I hit the tree.

Damn stupid place to have a tree.

Actually, I think I didn't quite hit the tree, I think I hit the branches. And it's a very small tree. Smaller now, because I broke a couple of the branches off. Sorry, tree. I said a few more bad words when I was lying on the ground.

And blood was pouring out of my head. Actually, it wasn't gushing, but it was dripping quite quickly.

So I picked myself up, and started to go back to the house, had second thoughts and wheeled the bike back with me, left it in the garage and headed for the utility room, where I used paper towels to staunch the flow. Pretty soon, the bleeding stopped, which is a relief because I'm on Warfarin to thin my blood, but my blood is good at clotting (I have Leiden factor, which is a bit like what Wolverine has but not as good). And then I thought, what next? Because I couldn't really see what I'd done, even with a mirror, because of all the hair.

So I phoned ladysolly to tell her the situation; she was down in London, visiting daughter(s) and was expecting me to meet her at the station when she got back, and I didn't want her to get home and find no drsolly, and blood all over the place; garage, utility room and kitchen. It wasn't nearly as bad as she would have imagined.

And then I drove myself to the Mount Vernon Small Injuries unit, which I go to for dog bites and suchlike, and which is ideal for this sort of thing because it's not jam packed like an A&E, and if there's not really much wrong with you, that's the place to go, they're open 8am till 8pm.

I was wearing a white t-shirt. That's significant, because judging fron the amount of bright red blood on it, I'd just been re-enacting the Texas Chainsaw Massacre. And I didn't want to change just yet, because why ruin two t-shirts? So I had to keep telling people "It isn't as bad as it looks".

The nurse was great. She cleaned it up, using sterile water, dabbing at it until she had all the hair out of the wound. She considered putting in a stitch or two, but decided, to my great relief, to use glue instead, and then a great big plaster on top, in case I ooze a bit. Which I haven't. So I'm mended, with glue.

That's it.

All my own fault. I *always* wear a helmet when I'm out biking ... but not when I'm just going round my back garden. If I'd been wearing a helmet, even this minor injury wouldn't have happened. And the tree should not have been a surprise. I mean, it's been there for years, I know it's there.

So I'm not going out tomorrow.

Weight report 66, Hobbyking and a pumpkin

15 stone, 6 pounds.

The delivery from Hobbyking arrived today - not bad, ordered on Monday, arrived Thursday. The batteries are smaller than I imagined, but they are definitely 14.8 volts, 5000 mAh, or at least that's what they say they are. I'll start soldering up stuff today.

And the pumpkin. I was bitten yesterday while bowling along on the bike; I felt an impact on my face, and then a very painful sting.

Today, the lower left side of my face is swollen up like a pumpkin. And it's itchy and slightly painful. I've put Aloe Vera on it.

Around Andover Again

Today I had a long day, cruising around Andover on the bike. I used 2 1/2 batteries again.
67 finds and a smattering of DNFs.

Because I opened up a battery, I discovered that they contain seven cells. At peak charge, that means 7 x 4.2 volts = 29.4 volts.  When they get down to their nominal 3.7 volts (25.9 volts), there's not much left. The voltmeter that I put on the bike is really useful!

There were a number of catastrophes during the day. The first was almost as soon as I set off - one of the bolts supporting the back rack went AWOL, and since the rack is supporting two batteries and my toolkit, that's about 15 pounds. So the back rack fouled the rear wheel, and I had to carefully cycle back to the car for repairs. I found a handy nut and bolt elsewhere on the bike that wasn't critical, and used that to support the back rack - this got me through the day.

The second catastrophe was my left boot; one of the metal strips that holds the bootlace got bent, and the bootlace wouldn't stay attached, so my boot was falling off. I stopped as soon as I could, and used the multitool that I always carry, to fix the boot.

The third catastrophe was probably the worst. As I was gaily sailing along, something hit me in the face, and then I felt a sharp pain in my jaw. I think I've been bitten or stung, I don't know what by. It's still irritating me; I'm hoping that it self-repairs overnight.

Stuff for the new battery pack has started to arrive. I have the 25 amp fuses and holders, and I have the 4mm and 2.5 mm cable for wiring everything. I expect more stuff will arrive tomorrow ... I hope!

Tuesday 8 October 2013

Hobbyking shipped today!

I ordered from Hobbyking yesterday. Their web site says that the order was shipped at 9am this morning. Woo hoo!

All the other stuff I need (cabling, fuses etc) is also on its way. Tomorrow, I'm going out caching, I have a late pass, so I won't be back till well after dark, probably knackered. So maybe Thursday I'll have parcels!

Sagepay called me back

On September 19, I called Sagepay because I thought I might be interested in moving my business to use their services. They took my details, and said they'd call me back.

On October 8, they called me back. Three weeks later.

I explained to the unfortunate sales guy who called me that I was extremely unimpressed with their level of service, and that clearly they were suffering from having too many customers, and that I would not be adding to their burden.

Spammed again

A few weeks ago, I was spammed by Lucas Frank Clothing. I phoned them up to get the email address removed, and they said they would, but they refused to tell me the source of the list they bought, claiming "Data Protection Act" which is absurd.  And annoying, so I reported their spam to the Information Commissioner's Office.

Today I got another spam from them. Same content, same email address, but with a slight change in a detail. So I phoned them up again. What a difference!

My complaint to the ICO had gotten back to them, and they'd had numerous other complaints. The guy there told me that they wouldn't ever be buying a spamming list again, because he had so many comlpaints, so that's good, another victim has been educated.

He was really certain that he'd removed the email address. I was equally certain that I've just received another email from him, and forwarded it to him. Soon the story emerged.

He'd bought 3.5 million email addresses, and he was spamming them 0.5 million at a time. It's clear, therefore, that my email address was in his list twice.

He thinks that the list vendor has gone out of business - that's the way it works, you see. Up pops a new list vendor, call them "Really excellent email lists", they spam their millions of email addresses with "3.5 million email addresses, all double-opt-in, all good and guaranteed for only £250". Some suckers buy the list, they send them the data. A month later they go out of business. And up pops a new list vendor called "Most excellent email lists".

I really ought to complain to the ICO about this second spam from LFC. After asking to be removed from their list, there's no good excuse for a second offence. But I feel sorry for him, he's actually the main victim in this. He's not only out of pocket to the tune of whatever he paid the list vendor (I'd guess a lot more than £250), he's also had to deal with numerous complaints, and his company has suffered a loss of reputation. So I won't complain.

Unless I get a third email from him.

And a second spam from Leasing Options Ltd. I called them and spoke to Craig. He's totally sure that they don't buy lists in and that I must have signed up for something (I didn't). And when I used the word "spam" to describe what he was doing, he was very upset. "Spam is what is sent by companies outside the UK offering dishonest stuff". No, Craig, spam is email sent via mass-mailing to people who haven't requested it. Possibly Leasing Options Ltd is in many respects a good and worthwhile company, but what you sent me is still spam. Eventually, he agreed to look into where they got my email address.

 ... later ... Craig called back. Yes, they had bought it in from a list marketing company, he doesn't know who, and they no longer buy in data.

And I finally got through to La Manga Holidays. I've been getting a steady trickle of spam from them for ages, and whenever I called their freephone number, there was no-one there. I called today, and was quite surprised to get an answer. They're taking me off their list, but they have no idea where they got the email address.

Monday 7 October 2013

Controlling the charger

The charger for the batteries will be powered by a PC power supply, of which I have several lying around spare. But it's occurred to me that I can be a bit more clever with this.

I have three temperature sensors; one of these is continuously telling me the outside temperature, and two are telling me the temperature in the Data Shed. I can divert one of those two, and use it to take the temperature of the battery while it is being charged. And I can monitor that temperature from, say, a Raspberry Pi, and switch the PSU off if the battery is getting too hot. I can also use the Pi to power-off after a preset time.

The iMax charger will, I think, be able to do all that itself. But it's more fun if I set it up myself.

Discount doorknobs

This is Kubra KOSELER from I am a domain name specialist.

As, we provide solutions to the companies to expand their businesses by offering the most targeted domain names for their brands. We have a searchable catalog of 3,500,000 high quality, commercially focused and generic domain names.

I wanted to contact you whether you would like to purchase or lease In order to reach out to more clients, this domain can be a great asset for you.

What an opportunity! If only I were a vendor of doorknobs.

Batteries bought

The order has been made! Four 5Ah, 14.8v batteries (which will be made up into a single 10Ah, 29.6v battery), four voltage alarms (one for each, so that it buzzes when the voltage gets down to a level that means "stop using the battery or it will fail permanently, 3.0v is recommended, but I think I'll set it at a more conservative 3.2v), an iMax 150 watt charger (and another, much cheaper, 80 watt charger which claims to be iMax but which I suspect is actually an iMax clone), a battery status displayer and balancer so I can measure and diagnose problems, a parallel charging board (which I suspect I won't be using), a 4s 6-way parallel balance lead (which I think I'll be using instead).

Also 20 connector plugs and sockets so I can wire up my charger and driver harnesses, 100 meters of 4mm cables, 100 meters of 2.5 mm cable (for the wiring harnesses; 100 meters is far far more than I need, but it comes in 100 m reels, and I'm sure to find uses for it in future), a temperature sensor that will connect to the iMax (and, I hope, tell it if the battery gets too hot so it can shut off charging), a temperature sensor for the bike, so that I'll know about any hot-battery problem while I'm riding, a car fuse (25 amps) for the charger and driver harnesses. Cable at a cross-section of 2.5 mm should be enough to carry 20 amps (the most I'm expecting), but I'm going to use 4 mm wherever possible

 Lots of safety here. Because those 2 kg of batteries are storing a million joules of energy. In practical terms, that would heat a kilogram of water to 240 degrees C. So I'm doing everything I can think of to make sure that all that energy doesn't get out of control. I'm not worried about the volts - 33 volts isn;t enough to give you a shock. It's the energy that's the thing.

The only "consumable" here is the battery - they only last a couple of years. Everything else should last pretty much indefinitely. The batteries themselves cost £68, which I think is really cheap.

The weight on the bike will be about 2.1 kg, compared with the 3.12 kg of my existing batteries, but should have a little bit more energy (I'm thinking maybe 15% more). I could build bigger batteries, but in my experience, it's really difficult to know how much power is left in a battery, but you certainly know when it's empty. So I'd rather have three 10Ah batteries (which I can carry in one pannier) than one 30Ah biggie.

Now what I have to do, is wait for the deliveries!

Saturday 5 October 2013

Yet more on batteries

I had a sudden thought. These Turnigy batteries are, it says, 14.8 volts, so with two in  series, that's 29.6.

But they aren't really 14.8 volts. That's assuming that the cells are 3.7 volts, but when they're fully charged, they're 4.2. So the total voltage isn't 29.6, it's 33.6 volts. And can my 24 volt bike handle that?

Well, I know it can handle 29.2 volts, it's already doing that. So I did a bit of internet research. This is called "over-volting", and it seems that people have happily overvolted to 36 volts without problems. So I guess it will be OK - the proof of the pudding will, of course, be in the biking.

I've totalled it up. Four of the batteries I've chosen, plus a charger, plus a parallel charging board, plus a parallel balance lead, plus four voltage alarms (one of each Turnigy so that I don't run it down below the level that makes the battery stop working forever) is about £113 pounds.

Meanwhile, I just had an email from the folks in China where I tried to buy a 20AH, 24 volt LiFePo4 battery at 8.1 kg. The battery got to the UK, and then got bounced back by UK customs, who say that they can't send it by air mail (although I suspect what happened is that it never actually left Asia). So they're offering me a refund, which I'm going to accept. The cost of that would have been £138 (plus £80 for air shipping), for a 24v 20AH battery. Twice the capacity of the one I'm planning to cobble together, at about twice the price. If I cobbled a 20AH battery, that would be LiCoO2 (which has some disadvantages, but has more energy per kilogram) and cost me £190 (and weigh 4.2 kg). So DIY looks to be cheaper than air shipping it from China.

The charger I'm looking at is the imax B8plus. That can charge up to 8 cells in series at up to 7 amps, and 150 watts. Will that be enough? Suppose I want to fully charge the whole thing in 5 hours. Each Turnigy is 14.8 volts, 5 ah, so one will pull 1 amp, 15 watts, so the whole thing will want 4 amps, 60 watts, so the charger can cope easily. If I extended it to 10 hours, which I'd happily do, because I only ever charge overnight, I could charge a battery with twice the capacity.

The imax has a couple of extra ports. One, costing a couple of pounds, is a temperature sensor port; that means I can make it monitor the battery while charging, and take action if it gets too hot. The other is a USB port, so I can monitor things from a computer, although that doesn't sound enormously appealing, because I'm guessing it would have to run under Windows, and would need me to be fairly close to the charger (I couldn't do it from upstairs).

Friday 4 October 2013

More on batteries

My researches have led me into the area of radio controlled models. They have much the same problems as electric bikes; a need for light, high-energy batteries at a good price.

Specifically Hobbyking

The first thing I had to learn about was C. C is coloumbs, a unit I learned about 50 years ago and now have no memory of. It's a unit of electrostatic charge, but it also expresses how fast you can get energy out of a battery. Suppose you have a battery that is 2 amp-hour (which is 7200 coloumbs). then if that battery is 20C (a common value for Li-ion) then it can deliver 20 amps continuously. I hope I have that right. So a 20C, 10AH battery can deliver 200 amps. I need about 20 amps at most.

So I'm looking at the Turnigy 5000mAh 4S1P 14.8v 20C. That gives me 5 amp-hours at 14.8 volts, and it can give 100 amps. If I put two of those in series, and another pair like it in parallel, that's 10 amp-hours at 29.6 volts with up to 200 amps at a cost of £68 (the last time I bought a 24v, 10ah battery, it cost £196). And the weight is 528 grams, so four is 2.16 kg (my existing batteries are 3.12 kg).

Now for charging. It's not just a matter of bunging 30 volts to it and waiting for it to charge - you have to be really careful with Li-ion.

I want to be able to charge it overnight, say 10 hours. that means charging each of the four units at 1/2 amp, to give the 5 ah. That's 2 amps at 14.8 v,  which is 30 watts. So I need a 30 watt charger. But I'd like to double that so that I can use twice as big a battery, so the charger I want looks like the HobbyKing ECO8 150W 7A 8S costing £30; that will give plenty of watts and amps, and lets me charge 8 cells at a time, while simultaneously balancing them. And to power that, I'll use a PC power supply (cost zero because I have loads of them). This is my Battery Management System; used on charging, which is when the main issues happen, but not on discharging, which means it doesn't need to be a permanent part of the battery.

So, balancing. If you just put 15 volts across the 4-cell 14.8 volt Turnigy, the four cells that make it up, won't charge evenly, and that could be bad, even catastrophic. So what this charger does, is charge each cell separately so that they all get taken up to 4.2 volts. I think I can do all four of the Turnigy batteries in parallel at the same time, if I use a splitter costing a couple of pounds. I'd package the splitter up with the batteries so I can just plug the charger into that, put in a car fuse on the output that will blow at 25 amps (for belt-and-braces safety) and take the output to a kettle plug that will plug into my bike motor controller. I won't need a switch, because unplugging the kettle has the effect of a switch.

The cells are nominally 3.7v, hence the 29.6v total. But when fully charged they are 4.2v, for a total of 33.6v. I hope the bike can handle that! If I let them go down to 3.0v then that's 24v total, so that would be a good point to cut off the power and put in a new battery.

What I don't know, is whether that 5000 mAh is real. Because when I was looking at the 18650 cells, the manufacturer's boast was usually somewhat more than reality; sometimes a lot more. More research required.

Also, are the batteries protected against over-discharge? If you over-discharge a Li-ion, that leads to it never working again. More research required. But £2.66 gets me a loud low-voltage detector which will monitor each cell of on battery, so maybe I get four of those.Plus I have my voltmeter on the handlebars so I can monitor as I ride.

Hobbyking also sells a "Lipo bunker", a steel case that you can put the battery into while charging if you're paranoid about the possibility of it overheating. It looks a bit like an ammo can ... and I can use one of my ammo cans for this!

So, this is looking to be a better proposition that 50-odd 18650 cells.

Thursday 3 October 2013

Bike Battery

 When I went out yesterday, I used the bike intensively, and I completely discharged two of the batteries, and I'd guess I half-discharged the third. So I do have enough batteries to keep me going all day - but one day, I'll need to replace them, as they only last a couple of years.

It has occurred to me that, since I'm just putting the bike battery in the panniers, it can be any shape or size I want. And that means, maybe I could make my own. Here's a useful link

First, some nomenclature. A cell is one (usually) cylindrical thing that pushes out electricity; a battery is a whole bunch of cells, wired up to give the voltage and current that you need. So, for example, with two 3.7v cells, you can put them in series to get a 7.4 v battery. Or put them in parallel to get a 3.7v battery with double the power. And inside my 24v battery, I see seven separate objects labelled "XH259-10J", which are in an aluminium enclosure, and which I will call "cans".

I did a bit of research. I can buy a li-ion cell size 18650 for around $3, That give me 4.2 volts, 2.2 amp-hours. Seven of those in series would be 29.4 volts (25.2 when discharged), 2.2 amp-hours, and with five of those sevens in parallel, I have 11 amp-hours, which is the capacity of the batteries I'm using. so that's about $105. Add $16 for cell holders, that's $121. The cells weigh about 50 grams, so that's 1.75 kg. My existing 24v (actually 29.2v when freshly charged) 10AH bike batteries are 3.12kg; that includes the casing and the battery management system (BMS).

What's a BMS? I think it stops you from overcharging the battery, or from letting it get too discharged (Li-ion batteries stop working altogether if you discharge them too much). And it stops you from pulling too much current. It can also worry about the temperature of the cells.

A BMS can also balance the cells. Without balancing, the cell of smallest capacity is a “weak point”, it can be easily overcharged or over-discharged while cells with higher capacity undergo only partial cycle.

If I use protected cells, I might be able to work without a BMS, although I would put in a fuse to protect against short circuits. Protected cells have a small circuit board that stops the charging or discharge of the cell in certain circumstances. Some of the circumstances in which the circuit include: Over-Charge, Over-Discharge, Short-Circuit, and in some cases, overheating. The protection PCB resolves most of any safety issue for LiCoO2.

LiCoO2 (lithium-cobalt, commonly called Li-ion) or LiFePO4? LiFePO4 has a smaller energy density and are, it's said, slightly safer. But LiCoO2 is lighter. Voltage is around 3.7-4.2 for LiCoO2 and 3.2-3.6 for LiFeP04. So, 7 LiCoO2 cells are 29.4V, whereas 8 LiFeP04 cells are 28.8v.

LiFePO4 can be charged 2000 times; LiCoO2 can be charged 1500 times. Not a difference that sounds important to me.

LiCoO2 can be charged at 2 amps, discharged at 5 amps. So four in parallel would discharge at 20 amps. LiFePO4 can be charged at 2-6 amps, discharged at 30 amps. So four in parallel would discharge at 120 amps. I'm not bothered by how long it takes to charge, as long as it will charge overnight. So I'd be happy to charge a 10Ah battery at 1 amp, since that would take 10 hours. For discharge, a 24v 250w motor wants 10 amps, a 500w motor would want 20.

LiCoO2 lasts for 2-3 years; the electrolyte crystallises, and you lose capacity.

LiCoO2 gives 4.2 to 3.6 volts. and stores (in 18650 size) about 2200 mAh (2.2 amp-hours)

4.2V Full 100%
4.1V About 90%
4.0V About 80%
3.9V About 60%
3.8V About 40%
3.7V About 20%
3.6V Empty

LiFePO4 stores (in 18650 size) about 1100 mAh

So, all things considered, it looks like I want  LiCoO2 (Li-ion) protected cells, and expect to repelllace them every three years.

Looking at my existing 24V battery, inside there are seven cells each in an aluminium can (or so it appears, I think that actually each of the things I see is a battery of seven cells) and a pcb (the BMS, I guess). Each canl is 127x65x16 mm, which is about the size for seven 18650 cells (they are 18 mm by 65 mm long, hence the name 18650). The cans are 4.1v, so they must be seven cells in parallel inside the thin metal can. So that would mean 49 cells altogether. Seven freshly-charged  LiCoO2 cells gives 29.4 volts, which is what I get on a newly charged battery. To give 10 amp-hours, each cell would be 1430 mAh, which sounds right for this sort of cell - I've seen it quoted as between 1300 and 2400. 18650 cells weigh about 45 grams, so 49 of them would be 2.2 kg (when I weighed them, they were 3.12 kg, but that includes the casing and the BMS).

So, suppose I made up my own battery. I put seven 18650 cells in parallel, and that makes one block.  I run seven of these blocks in series, that's 2.2 kg and 126x126x65 mm. I should be able to get 5 amps per cell, but it's better (you  get more out of the battery) if you only take 3 amps. But with seven in parallel, that's 21 amps, which is plenty.

Here's a very comprehensive battery test for 18650 cells. One of the first things that you notice, is that when the manufacturer says a cell is 3000 mAh, you'll probably only get 2500, and it could be a lot less.