Thanks to all for the info... Between this forum and the others that you folks pointed to me, I've spent the last 3days absorbing all the info I can. I must say that I'm finding my idea a little hard to implement given current battery technologies and such.

However, I have all my questions answered, and thanks Morph for the battery info. I think I can build the BMS I need and use it for all the LiFePO needs, all questions on range and charge answered and especially the regen stuff. I never expected to get a lot back, but there are some great ideas for optimizing return, critical for me = distance between charges.

I just can't avoid going to the heavier (2.5kg) 40 AH cells, but at least I should have no problem keeping the investment up to snuff.

Wiring the battery packs is going to be a little tricky, but I'll be running seperate cabling for a cell monitor (Cell log is nice, but some others have better features), balancing charger and the BMS. I doubt I'll ever lose a cell except to some wierd mechanical failure.

Some of Doctorbass's little experiments are really tempting, but I find 70km/h a little scary (I have hit 60 peddling, and then I hit the car...)

As I build the kit, I'll post pics. Still thinking of going recumbent for the lower wind resistance.. *sigh*