BM2 Bluetooth 12V Battery Monitor

Bluetooth battery monitor that bolts to the battery posts and reports voltage to your phone every few minutes. App alerts fire when voltage drops below cranking threshold — you find out the battery is dying while it's still parked at home, not at an interstate rest stop. Direct-to-post wiring eliminates the voltage drift that dashboard-mounted monitors suffer from. Compatible with AGM, gel, and flooded 12V batteries. About the size of a postage stamp, IP65 water resistant, and the kind of install that pays for itself the first time it saves a battery swap.