The Trollbridge12X24® Combiner allows you to charge your 24 volt trolling motor battery from the 12 volt alternator on your main engine or trailer hook-up without any risk of discharging your starting battery. It works by automatically putting two 12 volt batteries in series when you need to run the trolling motor and in parallel for charging. Charging is automatic when the main engine is running and the starting battery has at least 13 volt charge. When not trolling, the second trolling battery backs up the first trolling battery which can be used as a house battery.

The Trollbridge12x24 is suitable for installations with alternators up to 100 amps and 24 volt trolling motors up to 85 amps.

For larger installations you can use the Trollbridge2400 for 200 amp alternators and motor up to 500 amps.

If you DO want to use your starting battery for running the trolling motor you should purchase the Trollbridge24


    • Fully automatic, no switches or connectors to change
    • Both batteries operate in parallel when not trolling
    • Charging is automatic when the main engine is running
    • The bottom battery can be used as a house or starting battery even when trolling
    • The two trolling batteries do not have to be matched or balanced
    • A single output 12 volt charger will charge all batteries
    • Works with 3 battery systems, starting and 2 trolling, or in conjunction with a house battery
    • Can be conveniently located with the batteries
    • Rated for 12 volt alternators up to 100 amps
    • Rated for 24 volt trolling motors up to 85 amps
      . . . Contact for larger version, 500 amps, 16 horsepower, 12KW
      . . . For use on 24 volt anchor winch, bow thruster, hydraulics etc..
    • Green LED indicates 24 volt output active
    • Amber LED indicates charging in progress
    • Nearly UNLIMITED warranty
    • Charging is done at 12 volts so your motor never sees charging voltages
    • Over 99% efficient – faster charge – no wasted power – no heating
    • Waterproof – rated IP68 Protected from long term immersion
    • Ignition rated for explosive atmospheres
    • No voltage drop so batteries reach full charge
    • No voltage drop so motor gets full power
    • No wasted power, no heat sink or cooling required
    • No modification to alternator or 12 volt engine wiring
    • Simple 5 wire basic installation
    • Comes with all cables for basic hookup
    • Draws no current when off – no on/off switch needed
    • No diodes to burn out if accidentally shorted
    • Withstands ambient temperature to over 175 F (80 C) for engine compartment mounting
    • Compact, Only 4″ long including mounting tabs, 4″ wide, 2″ high (plus cables)
    • This product has not been shown to cause cancer in laboratory rats.


Additional information

Battery Type

Lead Acid/AGM, Lithium ION