ProMariner 31410 On-Board Charger The 12/24V, 10 Amp, 2 battery bank ProMar 1 5/5 waterproof battery charger incorporates solid state and fully automatic technology that eliminates the need to use portable battery chargers for charging each battery on-board one at a time Charge, condition and maintain batteries with a built-in safe maintenance mode At-a-glance AC power, charging and ready / maintain LED indicators Automatically charges and maintains your engine crank battery while distributing all remaining charging amps to your trolling motor batterie(s) Completely waterproof & shockproof. Dual in-line DC safety fuses (multi-bank models), reverse polarity, ignition and temperature protection