Battery Vehicle Society

Looking further into how light a bike could be has thrown up a design by Derbi, intended as a proof-of-concept design for a light weight dirt bike. The bike is the Derbi DH2.0, a 100cc, 8hp bike that weighs just 39.9kg. It looks like my idea of using top end downhill racing mountain bike components ...

If they are going to allow streamlining, then that makes the very light monocoque a definite contender, as it wouldn't weigh any more if it were streamlined. Top speed would increase too. At the moment it's the power requirement to maintain a reasonable speed on the hills that is the limiting factor...

The office I used was the one in Bournemouth (actually it's in Poole, but for some reason it's still called the Bournemouth office by DVLA). The two people I've dealt with at that office have been extremely helpful, which to be honest is the experience I've had with other DVLA local offices when pla...

An update. Today was a good day, not only did I finish the battery packs last night, but the man from the local DVLA office came around to "inspect" the bike. As usual, the local DVLA office went out of their way to help, unlike their comrades at Swansea who are, frankly, numpties. The cha...

Thanks for the reminder about those big model motors, I'd forgotten about them as a possibility. They need a fairly low voltage as I recall, primarily because high voltage brushless/sensorless controllers are fairly rare beasts and only available up to around 60V. Still, the motors have a pretty hig...

I hadn't thought of that, Malcolm, but you may well be right. I'm not sure that it's the best way to achieve this objective though, as the "money no object" crowd will just take the hit, I suspect. I'd love to see a limited budget, private entry, category that would encourage innovation fr...

I understand the rolling resistance/aero drag issues well enough, Paul, and accept that bigger bike tyres don't seem to be supplied in high modulus compounds. Smaller ones do seem to be available with a reasonably high modulus, low hysteresis, compound though. They are aimed at the "big moped&q...

There is another BMS kit that has been designed by a few guys on the Endless Sphere forum. I've just bought a 16 channel kit for my LiFePO4 pack. The full circuit diagram, together with the story of the development of this project, is on these two ES forum threads: http://endless-sphere.com/forums/v...

Many thanks for that, Malcolm, it's comforting when pure hypothesis gets confirmed by a real world data point! My guess is the rolling resistance for your bike might be very slightly higher than for my lightweight machine, so if anything my present model probably errs on the side of being slightly p...

I understand the paranoia about one or two "overly zealous" police officers, but the fact remains that you cannot be convicted of an offence if you haven't broken the law. The bench will want to see evidence from them that shows beyond reasonable doubt that you have committed an offence. H...