I fancy a little project for my missus.Before i converted my mountain bike with a bbs01 i used to poodle about for years on an old electric bike someone gave me.Its a dutch bike, totally the look that a woman wld like (used to sometimes feel a bit self conscious). It has a 200w rear hub,20 "wheels,no gears,just a 16t or 18t sprocket.The display is just a battery charge indicator.The battery is 24V SLA. Two wheelchair batts in the case which i replaced for 40 quid.It will only do maybe 10-12 miles now and anything more than gentle hills is kneecap popping. So im wondering if i bought a cheap lithium battery would it work or blow the controller.Also will it give it a bit more power.Seems a shame its just gathering dust now ive got the bafang.It would suit her,as she hates complicated stuff like gears.I can take the controller out if anyone can help and needs more info.I know theres 3 not 2 wire connections to the battery.Thanks