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Saturday, 16 August 2014

Testing bike.2

I took the bike out for a test run. It's powered by 12s of Lipo. The summary of my testing, is that it's the bike I plan to take out when I next go out geocaching. Which means I'm happy with it.

In low gear, the top speed was 12mph, in top gear it was 20 on the level. That's pretty good for a 250 watt motor.


I'm actually happy to run most of the time in low gear; when I'm on a bridleway, if I'm doing 10 mph then I'm going pretty fast.

I took it to my local steep hill test road. It climbed it at 7 or 8 mph, with only a very slight encouragement of pedalling; most of the hill it could climb without any help.

The voltage display is nice; the watts display is good, but I have my own wattmeter, which revealed that the max amps was 15 (not surprising, that's set by the controller) and the max watts was 750 (which is because I was pulling 50 volts x 15 amps). It's also nice that there's a speedometer. You can choose units of miles or kilometers.

There's 5 levels of PAS; I haven't tried that out as I prefer throttle. There's also a level which is "walking speed", which is about 4mph, and the bike keeps on going as long as you have your finger pressed on the display's button (which means that if it runs away from you, it'll cut power).

The thermometer on the bike display is useless. I think it's displaying the temperature of the air, it certainly isn't showing the motor or controller temperature. My own thermometer (an aquarium thermometer, cost me about a pound) turned out to be excellent. I checked its display with an infra-red thermometer, and by feeling the motor. The axle is hotter than the casing, and it peaked at 36 degrees C, feeling really quite warm (but remember my blood heat is about 40, so not really hot). It might be possible to put a few more amps through the motor.

The autoshift does work; when the speed falls to around 7 or 8, it changes to low gear, and at 12 or so it changes to high. But, obviously, it has no anticipation. When it changes gear, you lose power for about a second. My feeling is that I'll prefer to make my own choice when to be in low and when to be in high, based not only on my current speed, but also on what I can see coming up ahead of me. So I think that for me, the autoshift won't be very useful.

Which means that I could replace the controller with any controller that will let the motor go in reverse at full speed.

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