ATV Electronic conversion: Final part (part 2)

Previously in the story, I had finished winter-long update of cheap Chinese kids' ATV whose 2-stroke engine gave up way too soon to electric one, and then kid overloaded and burned out electric motor in less than 20 minutes of driving.

So I ordered a few more parts. I got new motor, 300 watt one now (previous 350 watts) to lessen load to battery a bit, and larger (104-tooth IIRC) rear sprocket to replace previous one, to bring gearing down even further (and to reduce load to motor, also upping drive torque a bit).

Sprocket was more challenging to change, as compatible sprockets with three-point attachment at radius I needed wasn't available in larger sizes. In the end, I just driller holes to old sprocket (original one, for different chain) and bolted that together with new one. This moved chain line a bit, but adding a spacer to motor sprocket fixed this.

Replacing motor was also simple, take old out, new in. This time I however added a thermal fuse in between motor and controller and zip-tied it against motor housing. Thermal fuses are handy as they permanently blow out when temperature rises too high, protecting the motor from overheating. Of course I used handily available Abiko connectors for that so it can be easily changed (also, soldering thermal fuse to a wire is very, very difficult; heat from soldering iron will blow it very easily!).

And now we're rolling again. Thermal fuse blew relatively soon (30 min or so), but that's okay; I used fairly conservative (low) temperature value at first. And it's easy to change so I think we're good to go now.

Now, for next iteration (if I were to make one, I'm not planning to anytime soon!) I'd look for more powerful engine; 500w 48v or something like that, and try to work out gearing so that top speed would be about the same (20 km/h). This would hopefully make the load on engine lower, allowing driving in more difficult terrain.

I did dream about converting a motorbike, something old 250-500cc bike like Suzuki GS500 to electric, but based on my calculations I'd need about 10kW of power to have nice "city-bike" with top speed of around 100km/h. I'd be okay with that power figure, but such motors, along with suitable battery packs for it, are just impossible to get here, so guess I'll be buying a ready-made bike sometime in the future - when they start bringing those here, that is.