Friday, 6 June 2014

A day of soldering

My big parcel from Hobbyking arrived today. Hurrah! Lots of new batteries, another charger (now I have five) and some bits and pieces.

One of my existing 4S batteries, is completely refusing to respond, so I'm glad that I ordered a 4s to replace it. But the main order was four 8s batteries. 8s means 30 volts; one of these little fellows is all I need to power my bike. It's 4 amp-hours, and only 820 grams (what I'm currently using is 5 AH, and 1050 grams).

As soon as I saw those 8s batteries, I could see a problem. They have a main power lead, like the 4s ones, but the balance port isn't an 8s cable, it's two 4s cables. So I contacted Hobbyking to ask how I was supposed to charge this up. They said that I needed an XH multi-pack balance board, which costs only £2.53. But the important thing was, they didn't have any. Not in their UK warehouse, and not in their Chinese warehouse. And if I asked them when they would be available, they wouldn't know (optionally, they would pretend that they did know and give me a date, and be really apologetic when that didn't happen). So now I have four 8s batteries, and no way to charge them.

And that's where my trusty soldering iron came in. I had some 8s extension cables. I cut one of them in half, and I cut two 4s cables in half, and soldered the two 4s pieces to the 8s piece. That's not as simple as it sounds; you have to connect the correct wires on each side, otherwise when you plug it into the battery, there's a bang and a cloud of smoke as 100 amps tries to rush across a wire thick enough for five amps. I won't explain here how the wiring goes, but if anyone needs to know, email me.

So I soldered it up, and also made an adaptor to convert the 4mm bullets that the battery comes with, to an EC5 which is my preferred power connector, and then I plugged it all in, and ... no smoke! So I powered up the charger, and plugged that in - still no catastrophic short. So I charged it up. And then I did the same for the other three 8s batteries. So now I have four 8s, 4ah batteries, which is 16ah at 8s, and which is probably enough for most days out.

It'll be pouring with rain tomorrow, according to the forecast, so we won't be going out caching, but if there's a dry spell, I'll use it to test the bike with the new batteries.

I also ordered six 2s batteries, because I found that running at 10s (37 volts) is a bit peppier than 8s. So I can put a 2s in series with an 8s (or a pair of 4s) to give me 10s any time I want a boost. And I had to make 4mm to EC5 adaptors for those, also. I ran out of 2s extension leads, so I ordered 10 more from China. And I wired up the new charger, so that I can use it to charge up to six 4s batteries at once. I now have five chargers; two for 8s, two for 4s and one for 2s (although I have some flexibility in that) and all of these are powered by old 2U PC power supplies that I consider too dodgy to use for PCs because they aren't reliable enough, but they're good enough for this purpose.

The last bit of soldering I did, was an idea I had when I was out yesterday. I'm using one of my bike batteries, via a step-down card, to charge up the PDA while I sit in the car for lunch. It occurred to me that I could use the big lead-acid battery that I keep in the car as an emergency start-the-car thing (and it also has a tire pump, and a cigarette-lighter socket). If I had the sort of plug that plugs into that socket, wired to an EC5, then I could use the lead-acid to charge my PDA (or even the main car battery). I took the plug from a dead inverter (I tend to keep things that break that might have useful components), and a quick bit of soldering gave me what I needed.

Another arrival today was a pair of Altura panniers. I like Altura, because they're sturdy, they fix to my rear rack in a way that means they can't bounce off, and yet they're quick release (and have a handy handle) so that when I encounter an obstacle, I only have to unplug one plug, lift the pannier off the rack, and then lifting the bike is about five kilograms easier. And believe me, that five kilograms makes a big difference! I got these Alturas second hand, but they're in excellent condition. I got them cheap because they're missing the fixing that attaches the pannier to the lower end of the rack. But A) I probably won't need that, and B) I can always use the fixing from my existing pannier, which is looking very sad and sorry, because I've had to glue patches to it because parts of it have worn away, because of the extreme abuse that it suffers.

Also today, my new camera arrived. It's like the GoPro, except it's a fraction of the cost. Same shape and size, same resolution. I can attach it to my bike handlebars, or to my helmet.

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