BattMon II was designed to be an economical Battery Monitoring System for smaller Electric Vehicles and NEV's. It can monitor up to 8 batteries (any voltage) and has an easy to read OLED Display. This display is even quite legible in direct sunlight.
The display will change color and flash if a battery goes too low or hi. There is also an optional Relay output board so you can hook up alarms, or something to turn down the throttle or charger.
If your 12v system does not share a ground with the pack, or if it is completely isolated, you will need to power the monitor from a 12v tap off the pack, and use a relay to turn the monitor on and off. If you purchase one with the monitor (see options below), it will be pre-wired into the monitor power cable.