|
Well one cell is 64 Wh, so 16 cells to get 1kWh. $27.50 * 16 = $440 / kWh.
You only really need a BMS if you want to come anywhere near close to either end of the charged/discharged state. Using it as a starting battery I know this won't be the case. The alternator will only charge it to roughly 50% (I'll be verifying this with testing that I will post later), and starting sure won't take that much power and then it will be topped off when the engine starts. If you can ensure that you aren't going to cycle it deeply at all as is the case for me, you can get away without a BMS. For anything else I'd suggest using one. At the very least you need a way to monitor the cells and watch it so they don't charge up too far or discharge too low. This is a pain and it is how I used to do things on my PHEV kit on the Prius. It gets old fast and you'll want something automated IMO.
|