What’s the best way to power your boat's electronics?
April 03, 2025
By Thomas Allen
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We’ve covered a lot of technology and related applications in this column, hopefully to a point that’s given you confidence to get out, experiment, and find a way to work modern fishing electronics into your arsenal. So, what’s the best way to power all this gear? If you’re running three, four, or even five graphs, quality power is critical. And as the electronics have evolved, so have the batteries meant to power them.
To learn more about lithium battery types and calculating amp hours, take a second look at “Screen Scene” from the latest December/January/February edition of In-Fisherman magazine. For the sake of our discussion here, let’s quickly review how to determine amp-hour (Ah) draw.
A quick Google search requesting amp-hour draw for Humminbird Solix 10-inch or whatever graph is rigged on your boat will return the necessary info. Add up the Ah draw per sonar unit and additional devices rigged to the battery and multiply that number by the hours you expect to fish, and that will give you the Ah demand that needs to be met.
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Clean Power Gone are the days of running your electronics on your house battery that’s also powering your starter, jack plate, livewell pumps, and, nav lights. It’s highly encouraged to have a dedicated battery set aside to run electronics exclusively. With most electronics packages featuring four to five graphs, plus GPS and other small accessories, the potential for interference is much higher—clean power through an exclusive battery solves most of these issues.
For our Starcraft and Smokercraft TV boats, we run X2Power. We have three 100-Ah lithium batteries rigged to power our 36-volt Minn Kota Ultrex , one X2Power AGM as our house and crank battery, and a single 125-Ah lithium battery powering our electronics package. The 125-Ah lithium will supply power for the electronics for about 13 hours—I’ve depleted it a time or two.
If you need more battery power, consider rigging two batteries in parallel to double your Ah output.
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Series vs. Parallel If you plan to do any of the rigging yourself, or at least be capable at troubleshooting when on the water, you need to understand how batteries work together. While there are a few companies making 24- and 36-volt batteries, the standard is rigging two 12-volt batteries for a 24-volt system and three for a 36-volt system. When rigging batteries together to increase voltage—typically used for trolling motor power—it’s called connecting in series. That means wiring a positive post on the first battery to the second battery’s negative post, and so on.
To rig something in parallel is to increase Ah output, by essentially double. It’s bad practice to rig two different batteries into a parallel system as you’ll stress the smaller battery. For example, lead-acid to lead-acid, or lithium to lithium, and match power: rig two 100-Ah batteries together for a combined 200 Ah; don’t rig a 75-Ah battery to a 100-Ah battery. Simply connect the positive posts to each other and the negative posts to each other and then you’ll connect your device or switch to a positive post on one battery, and the negative post to the next battery.
(Wiring illustrations courtesy of Minn Kota) Charging Charging these systems is straightforward. You will need to connect a multi-bank charging system to each battery in a series, and they will each charge on a standard timeline. When charging two batteries in parallel, you can charge them individually, or you can charge them as one battery, but you’ll need to connect the charger to one post per battery in the parallel rigging. Note, however, if you’re using one connection to charge a parallel rig, it will take twice as long to charge to full capacity.
Many battery companies now offer chargers specifically designed for the batteries they sell. This is fine, but it can occasionally complicate rigging. We run Minn Kota Precision On-Board Chargers on our boats, and you do have to select the battery type when you first set it up.
As long as you charge your system regularly and don’t let the batteries over deplete due to an unforeseen phantom draw, or not charging them for an extended period of time, you likely won’t have issues.
There are a few companies such as PowerHouse Lithium that have developed a charging system that converts the power out of the alternator on the big motor to usable power for lithium batteries. There’s a lot of science there I can’t speak to, but with a PowerHouse Lithium 12-, 24-, or 36-volt Run & Gun DC to DC Charger, you can charge a battery, or all of them while the big motor is running. These retail for $199.99 at powerhouselithium.com .
Main Power Switch A master power switch and a fuse panel installed exclusively for your electronics will eliminate a phantom power draw that could drain and damage your batteries. All these technologically advanced fishing electronics are amazing, but they do pull battery power when fully connected to the power source—even if they’re shut off. Most boats nowadays come with a built-in “house” power switch, but if you’re to add four, five, or more graphs on independent, clean power, you’ll certainly benefit by adding a master power switch for your electronics.
Specialty Batteries The main priority when shopping for batteries should be to get the most power in as small a package as possible—footprint matters when you’re increasing the number of batteries in use.
Dakota Lithium has a 135-Ah battery that serves two purposes: it features 1,000 cold-cranking amps (CCA), which cranks the big motor and accepts power via the alternator, and it comes in a Group 24 footprint, meaning it’s smaller than a Group 31, with more juice.
PowerHouse also has a 16-volt 100-Ah battery that will run four graphs and two extra devices for 10 to 16 hours. The battery provides clean, dedicated power that produces better clarity, runs 20 percent longer on a single charge, and because of the reduced amperage, the units stay cooler—and that means a longer life.
A few brands have developed 24- and 36-volt batteries that take up a fraction of the floor space as three Group 31s. Dakota Lithium has a 36-volt, 60-Ah in a Group 31 footprint ($1,499), and a 36-volt 110-Ah that measures just over 20 inches in length ($2,299).
The PowerHouse Run & Gun charger converts power from the big motor’s alternator into usable power for your lithiums. A handy device to generate day-long power without pause. BMS Systems and Warranties Yes, lithium batteries are expensive—typically more than twice that of a traditional lead-acid option. But most of them come with an impressive 10-year, or better warranty making it a more cost-effective investment in the long run.
There was a time early in timeline of lithiums when a spontaneous fire was extremely rare, but a concern, nonetheless. Thankfully, that’s not a risk any longer with the built-in Battery Management Systems (BMS) that come standard in all lithiums nowadays.
Battery companies worth investing in have a smartphone app that connects via Bluetooth to each battery individually so you can monitor remaining charge and overall performance. It’s very important to know how your system works so you can make educated decisions across the board when adding electronics or batteries to the mix.
It’s Worth It The battery market seems to be growing by the day and it’s easy to see how that can be intimidating. I’ve found if you’re willing embrace the learning process and become competent at understanding the best way to power your boat and gear, you’ll be confident in finding the best battery for you. The best power rigged the right way will keep you on the water longer, frustration free. And that means more fish in the boat.
