Last updated: August 20, 2026
Moving up to a 24 volt trolling motor is the upgrade most anglers are happiest with, right up until the battery order. Suddenly you are buying two of everything, the charger you own is wrong, and every forum thread turns into an argument about series connections within four replies.
The good news is that the buying part is simpler than the internet makes it sound. What matters is that the batteries are a matched pair, that they are true deep cycle, and that the charger you buy suits both the bank and the chemistry. The connecting itself is a job for someone qualified, and we will keep it that way.
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Quick Answer
What batteries does a 24V trolling motor need?
- Two 12 volt deep cycle batteries that match in brand, model, capacity and age, or one purpose built 24 volt battery.
- Never mix an old battery with a new one, or two different chemistries, in the same bank.
- Buy the charger with the batteries, because lithium and lead acid need different charge profiles.
- Minn Kota publishes the wiring guidance for its motors, and making the connections is work for a marine technician.
Bottom line: buy a matched pair or a single 24 volt unit, add the right charger, and have the bank connected by someone qualified.
Why 24 Volts in the First Place
Higher voltage lets a motor deliver more thrust while drawing fewer amps for the same power. Minn Kota’s own guidance makes that point directly: as system voltage rises, the current needed for a given output falls. That is why bigger boats move to 24 volt systems rather than simply fitting a larger 12 volt battery.
The practical effect is more thrust for heavier boats and better staying power in wind, without the enormous current a 12 volt motor of the same capability would demand. The cost is a second battery, a different charger and more weight in the bow.
Matched Pairs: The Rule That Saves Money
Two batteries in a series bank behave like one battery, which means the weaker one sets the performance of the pair. Buy both at the same time, same brand, same model, same capacity and same chemistry. A new battery paired with a two year old one will be dragged down to the older battery’s condition.
The same logic applies to replacement. When one battery in a pair fails, you replace both, however painful that feels. Slotting one new battery beside a tired survivor is the most common way owners spend money twice inside a season.
Do Not Mix Chemistries
Lead acid and lithium charge and discharge on completely different curves and must never share a bank. Flooded and AGM should not be mixed either. If you are switching chemistry, switch the whole bank and the charger together, and confirm your motor’s manufacturer supports the chemistry you are moving to.
Capacity: How Long Do You Want to Fish
In a series bank the amp hour rating does not add up, it stays the same as one battery while the voltage doubles. Two 12 volt batteries rated at a given capacity give you a 24 volt bank of that same capacity. Runtime therefore depends on the amp hour rating you buy, not on the fact that there are two of them.
Compare that capacity against the maximum amp draw your motor’s manufacturer publishes. Minn Kota lists a maximum draw per model in its support documentation and notes it occurs only intermittently, so treat it as the pessimistic case rather than the number you will see all day.
Four Ways to Build a 24V Bank
There are four common approaches, and the right one depends on budget, bow weight and how long your days are. Every one of them assumes the connection work is done properly, whether that is by a marine technician or by a dealer at fitting time.
| Approach | What you buy | Best for | Watch for |
|---|---|---|---|
| Two matched AGM | Identical sealed deep cycle pair | Most owners, most boats | Weight in the bow |
| Two matched flooded | Identical vented deep cycle pair | Lowest purchase cost | Water checks and venting |
| Single 24V lithium | One purpose built unit | Weight sensitive boats | Charger must suit lithium |
| Two 12V lithium | Identical lithium pair | Long days, existing tray fit | Confirm series use is supported |
The Lead Acid Route
Two matched group 27 or group 31 deep cycle batteries remain the default 24 volt setup, and for good reason. They are widely available, cheap to replace, and any marine charger on the shelf will handle them. The compromises are weight and the way voltage sags as the pair drains toward the end of a long day.
Measure the compartment before ordering. Two group 31 cases take a surprising amount of floor space, and both need proper trays or boxes with hold downs. Our guide to boxes, trays and venting covers what a flooded pair in particular requires.
The Lithium Route
Lithium iron phosphate cuts the weight substantially and holds voltage far more steadily under load, so the motor feels the same at the end of the day as at the start. A single 24 volt lithium unit also replaces two cases with one, which frees up bow space that small boats do not have to spare.
The catch is cost and compatibility. You need a lithium capable charger, and you should confirm that your motor manufacturer supports lithium with your specific model before committing. Our comparison of lithium against lead acid covers where the money actually goes.
Charging a 24V Bank
A 12 volt charger will not service a 24 volt bank correctly, and this is where owners get caught after the upgrade. The usual answer is an onboard charger with one bank per battery, which charges each battery individually and keeps the pair balanced, which is exactly what a matched bank needs.
Match the charger to the chemistry as well as the bank count. Lithium needs a lithium profile, and flooded, AGM and gel all prefer their own settings. Our onboard charger guide covers bank counts and amps per bank in more detail.
Where the Line Is on Wiring
Connecting batteries in series, sizing the circuit protection and running cable to the bow are not do it yourself topics on a boat. Minn Kota publishes wiring and battery guidance for its motors, and that documentation plus a marine technician is the right combination. This guide covers what to buy, not how to wire it.
That is not caution for its own sake. A trolling motor bank stores real energy, marine environments are wet and vibrating, and an undersized or wrongly protected connection is a fire risk rather than an inconvenience. Have it done once, properly.
Frequently Asked Questions
Do two 12V batteries double the amp hours in a 24V system? No. Wired in series the voltage doubles and the amp hour capacity stays the same as a single battery. Runtime therefore depends on the capacity you buy, which is why anglers who fish full days still shop for high capacity cases.
Can I use two different batteries for a 24V trolling motor? No. Both batteries should match in brand, model, capacity, chemistry and age, because the weaker one sets the performance of the pair and will drag the newer one down with it. Replace both together when one fails.
Is a 24V lithium battery worth it? If bow weight matters or you want steady output through a long day, it makes a strong case. If cost is the priority and weight is not, a matched pair of lead acid deep cycles does the same job for far less up front.
What charger do I need for a 24V trolling motor? An onboard charger with a bank for each battery, set to the correct chemistry. A single 12 volt charger is not a substitute, and using a lead acid profile on lithium or the reverse shortens battery life.
Can I wire the batteries myself? Series connections, circuit protection and cable runs on a boat are work for a marine technician, following the guidance your motor manufacturer publishes. The buying decisions on this page are yours to make; the connections are not the place to improvise.
The Bottom Line
Buy a matched pair or a single 24 volt unit, size the capacity against the amp draw your motor’s maker publishes, buy the charger at the same time, and leave the connections to a marine technician. For the wider picture, the main trolling motor battery guide compares setups by boat, and the lithium comparison covers whether the jump is worth it for you.