Dual Purpose Marine Battery
A dual purpose marine battery does the two jobs a boat asks of a battery: a hard burst of cranking amps to start the outboard, then hours of steady deep cycle power for the fish finder, pumps, lights and stereo. In lead-acid that was always a compromise. In lithium it is not: the packs we carry rate at 1,000 to 1,600 cranking amps and 135 to 150Ah of usable capacity, in the same Group 24 and Group 31 cases your boat already fits.
Dual Purpose Marine Batteries
Dual PurposeGroup 24Dakota Lithium 12V Trolling Motor Battery 135Ah DL+ (1000CCA Dual Purpose)
Dual PurposeGroup 31Ionic Lithium 12V 150Ah Dual Purpose Marine Battery (1600CA)
Dual PurposeDakota Lithium 36V Trolling Motor Battery Set 60Ah DL+ (3 x 12V Dual Purpose)
Dual PurposeDakota Lithium 36V Trolling Motor Battery Set 135Ah DL+ (3 x 12V, 1000CCA Dual Purpose)
Dual PurposeDakota Lithium 24V Trolling Motor Battery Set 60Ah DL+ (2 x 12V Dual Purpose)
Dual PurposeDakota Lithium 24V Trolling Motor Battery Set 135Ah DL+ (2 x 12V, 1000CCA Dual Purpose)
One Battery, Two Jobs, No Compromise
Lead-acid makes you choose. Thin plates crank hard but die when drained; thick plates survive deep cycling but crank soft, and a lead “dual purpose” battery splits the difference by being mediocre at both. LiFePO4 does not have plates. Its cells and BMS deliver full cranking output at almost any state of charge and still let you use 80 to 100 percent of the rated capacity, which is why a dual purpose lithium marine battery can start a 200 horsepower outboard at dusk after running electronics all day, and do it again for thousands of cycles.
Who Should Buy Dual Purpose
Center consoles, bay boats, pontoons and runabouts that run one or two batteries for everything are the natural fit: the pack starts the engine and carries the house loads with no second bank to wire or charge. Bass boats with a bow-mount trolling motor are the exception. Give the trolling motor its own deep cycle bank so an afternoon of trolling never touches the battery that has to start the outboard, and use the dual purpose pack as the cranking and electronics battery.
In the Store Today
The Dakota Lithium DL+ 12V 135Ah pairs 1,000 CCA with 135Ah in a Group 24 footprint at about 27 pounds, backed by Dakota’s 11-year warranty. The Ionic 12V 150Ah Dual Purpose steps up to 1,600 marine cranking amps and 150Ah in a Group 31 case, with Bluetooth so you can read the state of charge on your phone. Both ship free with their full manufacturer warranty.
Dual Purpose Marine Battery FAQ
Is a dual purpose battery good for a trolling motor?+-
It works, and on a one-battery boat it is the right answer. On a boat with a bow-mount trolling motor, the better layout is a dedicated deep cycle bank for the motor and the dual purpose pack for starting and electronics, so a long afternoon of trolling never drains the battery that has to start the engine.
How long will a dual purpose lithium run my electronics?+-
Amps times hours. A fish finder, livewell pump and stereo drawing around 8 amps together run roughly 15 hours on a 135Ah lithium, because 80 to 100 percent of a lithium battery is usable. The same load flattens a “100Ah” lead-acid battery in about six hours, since only half of it is safely usable.
Dual purpose or deep cycle: which do I need?+-
If the battery ever has to start an engine, dual purpose. If it only ever runs a trolling motor or house loads, a deep cycle pack gives you more amp hours for the money. Many boats run one of each: a dual purpose at the transom and a deep cycle bank at the bow.