Current technology for car batteries are extremely heavy lead acid batteries. Commercial attempts at replacing these lead acid batteries with lithium are available and all of them use a 4 series configuration due to the the fact that 12v car systems charge at ~ 14.4 volts.

Unfortunately, this is a waste of the cells at they typically end up being charged to about 10% charge or 3.5V/cell. A better solution is to use super capacitors which are declining in price, married with a single cell lithium battery to provide top up and running accessories.

The hardware would provide the following:

- capacitor balancer
- single cell stepup
- over charge protection
- step-down charger from 14.4+v
- over current protection
- over discharge protection
- close to zero power draw when idle

The final product should a safe lithium battery solution that is more cost effective, lighter, and environmentally friendly.