Battery Vehicle Society

They really are looking to push the boundaries a bit with this race. Those qualifying guidelines pretty much exclude any sort of budget privateer entry, as the costs will be pretty high to develop something to do 100mph max and average over 50mph. As the power requirement goes up in proportion to th...

The specs for industrial chain drives tend to assume that the thing will be run at rated power all day, every day, will probably not get as much care and attention as it should and will have a service life that's many times longer than the chain and sprockets on a bike. Chain drive ultimate torque l...

All good points, Peter, many thanks for the useful contribution. The shaft problem can probably be overcome fairly readily, I hope, by using one of the proprietary clamp-type fixings, although the motor bell itself it held on to the shaft by grub screws. I've discovered that the shaft is just a plai...

I agree that gears would make a good final solution, but for a proof-of-concept model they would entail some extra work in machining up a gear case, sealing it to contain the oil and fitting seals to the motor input shafts and the output shaft. It's all perfectly possible to do, but would be wasted ...

I know it might sound a bit odd, but have you thought of using chain drive instead of belts? A chain drive running in a sealed oil bath will be extremely long lived and reliable, it's only really the dirt, corrosion and lack of lubrication that makes them wear so quickly on bikes. You may find that ...

Cedric Lynch gives a useful "rule of thumb" way of estimating whether direct drive will work OK for his motors. He suggests multiplying the weight of the vehicle (400kg) by the maximum speed in km/h (80) and if the result is less than 30,000 you're OK. In you case, the answer is 32,000, wh...

Chain drive is surprisingly efficient, losses are only around 2% to 3% for a well-maintained chain. Gears can be efficient, but bevel gears in a bike drive shaft arrangement, particularly if cut so that they aren't excessively noisy, will probably lose around 4% to 5% or so. The differences aren't t...

Thanks for the contributions, chaps. I think that a large brushless motor, using RC model motor technology, would be a better answer, but at the moment the more powerful (up to about 12kW) RC motors are very expensive, around £800 each. The multiple small motor approach would have a small efficie...

Not much to add to the project, as I seem to be bogged down with getting the bodywork sorted (new combined seat/dummy tank/side panels etc). I've taken advantage of the lull whilst waiting for epoxy to cure by finishing off the instrument cluster. I ripped out the old rev counter and have adapted a ...

When you mentioned One million EV's, I thought 'He must mean the Prius!?'. I really couldn't beleive it though, it's totally irrelevent to this discussion. With respect, it's not, as the Prius is a pure EV when pulling away from a standstill, or reversing/slow speed manoeuvring, which is precisely ...