We've chosen some batteries for you that will work well with this most kits. The standard BMC V1 kit is designed for a 36V battery pack. Just about any battery pack rated as "36V" (actually more like 41.5 volts when charged) will work with this kit. Different battery chemistries have varying weights, lifespans, prices, and discharge characteristics. (See below for more information). With a 36V pack, the top speed of the BMC V1 kit will be about 22mph. This is as fast as a pro bike racer. For those who want even higher speed, upgrade to a 48V system and battery.
For the lightest weight, longest lasting battery on the market, add a 36V 10Ah Lithium-Iron-Phosphate polymer battery. This battery has a nice form factor that fits nicely in a trunk bag, side pannier, Xtracycle pocket, or any other mounting option you come up with. The battery weighs in at just under 8 lbs (20% lighter than other LifePO) and comes with a charger optimized for maximum performance. Rated for more than 1,500 charge/discharge cycles. Size 4" x 3.3" x 10.4" . For more range, this battery is available in higher capacity options on our battery page.
For a less expensive option, add a 36V 8Ah Nickel-Cadmium battery. This battery is lighter and longer-lasting than Lead-Acid, but still relatively inexpensive. It is a durable battery chemistry that can handle cold temperatures. 500-800 charge/discharge cycles. Battery weighs in at 13 lbs and comes with a 2-Amp charger. This battery also comes in a rectangular form that fits in trunk bags or panniers, or in a triangular form which fits in the diamond frame of many bikes.