The Trollbridge 24 allows you to charge your 24-Volt trolling motor batteries from the 12-Volt alternator on your main engine, your trailer hookup, or any single or multi-output 12-Volt charger. It is designed to allow using your starting battery as one of the two (2) trolling motor batteries.
It works automatically by connecting the 12-Volt starting battery and the 12-Volt trolling motor battery in series for trolling motor mode and connecting them in parallel for charging mode. It is bi-directional, so when not trolling, the second trolling battery backs up the starting or house battery. When using the starting batteries as one of the trolling batteries, you should be alert to the charge remaining so you can start the outboard motor. Using a higher capacity starting battery can help.
The Trollbridge 24 contains a built-in Combiner that isolates the starting battery from discharge.