This is an update to my initial posting last July. It didn’t take long to figure out the lead batteries were not going to cut it for the sort of high performance bike I had in mind. So shortly after I moved I replaced them with a LiFePO4 pack from Yesa. I got this straight from the manufacturer in China at a considerable savings over other similar quality packs from retailers here. I can only speak for my experience.. but the guys at Yesa were top notch to deal with and after more than 6 months putting their batteries to work I’ve had no problems. The Li pack is lighter and I relocated it for better balance on the bike. With a fresh charge on level ground it can sustain 40… but 35 is a normal top speed once you get past the first few miles.If I had it to do over.. I might go with a 72v setup and a motor with more windings. That would allow for lower power draw but still ample speed when you need it. Continue Reading for more technical details..