I make my own packs-- buy chinese cells (BMSbattery,or greenbatterybike ,or another) easy with big cells ,don't save much but get a better battery front mount under & ea side .The Web sites fool you into buying the low bms then have to buy another but one learns from mistakes yet agai wish i could upload a pic so you;d see the shape, made from 2 lengths 65mm pvc downpipe