How to Hook Up a 24 Volt Trolling Motor Battery Setup

A 24-volt trolling motor can give you the extra thrust and runtime you need for bigger boats, longer days on the water, and tougher conditions like wind and current. But before you can put that power to work, you need the right battery setup.

The good news is, you have a couple of options. You can run a 24V trolling motor with one 24V battery or connect two 12V batteries in series to create a 24V system. Either works!

If you’re going with two 12V batteries, we’ll walk you through exactly how to connect them, what you need for safe trolling motor wiring and charging, and when switching to a single lithium trolling motor battery might make your setup even simpler. Let’s get started.

Understanding 24V Trolling Motor Systems

So, how do two 12V batteries power a 24V trolling motor?

When you wire two 12V batteries in series, their voltage combines while the amp-hour capacity stays the same. That means two 100Ah batteries wired in series give you 24V at 100Ah, not 200Ah.

That higher voltage comes in handy when your trolling motor needs more thrust. Think larger boats, more weight on board, or days when you’re fighting wind or current. A 24V setup can also deliver the same amount of power with less current than a comparable 12V setup, which can help cut down on heat and power loss in the wiring.

One important thing before you start: use two batteries that match in type, capacity, and ideally age. And make sure you’re wiring them in series, not parallel. Parallel wiring keeps the system at 12V, which won’t give a 24V trolling motor the voltage it needs.

One 24V Battery vs. Two 12V Batteries

So, do you actually need two batteries for a 24V trolling motor? Not necessarily.

You can power a 24V trolling motor in two main ways:

• Two 12V batteries wired in series: This is a really common setup and gives you the 24 volts your trolling motor needs while keeping the same amp-hour capacity.
• One 24V battery: A single 24V trolling motor battery gives you the voltage you need without having to connect two separate batteries together.

Both setups work. Two 12V batteries give you more options when it comes to battery size, while one 24V lithium battery keeps things a little simpler with fewer cables and connections. It really just comes down to what works best for your boat!

But if you’re using two 12V batteries, here’s what you’ll need and how to hook them up.

What You’ll Need

Before you start hooking everything up, it helps to have the basics ready. Most of what you need is pretty simple.

But having the right cables, wiring, and safety pieces makes the setup a lot easier:

• Two matching 12-volt deep-cycle marine batteries: If you’re wiring two batteries in series, they should match in type, voltage, capacity, and ideally age.
• Battery jumper wire: You’ll need a heavy-gauge jumper wire to connect the two batteries together.
• Circuit breaker or fuse: Use the size recommended by your trolling motor manufacturer.
• Marine-grade wiring: Use wiring made to hold up around water and in a boat.
• Ring terminals and heat shrink: These help keep your connections secure and protected from corrosion.
• Multimeter: This lets you check that your setup is actually giving you around 24V before you turn the motor on.
• Cable clamps or ties: Use these to keep your wiring secure and away from anything sharp, hot, or moving.

Choosing the Right Wire and Circuit Breaker

No matter what type of batteries you’re using, make sure your wiring and circuit breaker are right for your trolling motor.

The wire size you need depends on your motor and how far the wiring has to run. Longer runs may need thicker wire, so check your trolling motor manufacturer’s recommendations before adding or extending any wiring.

You’ll also need the right size circuit breaker or fuse to protect the motor and wiring. Many 24V trolling motors use a 50- or 60-amp breaker, but the right size depends on the motor, so check the manufacturer’s recommendation for your setup.

If you’re using a single 24V lithium battery, you won’t need the extra battery cable used to connect two 12V batteries in series. With two 12V batteries, you will.

Step-by-Step Trolling Motor Wiring Process

Ready to hook everything up? Start with both 12V batteries fully charged and make sure your trolling motor is disconnected. It also helps to label the batteries Battery 1 and Battery 2 so it’s easier to keep track of what goes where.

1. Connect the two batteries.

Use a series jumper wire to connect the positive terminal of Battery 1 to the negative terminal of Battery 2. Make sure that jumper is the same gauge as your trolling motor leads.

2. Connect the black trolling motor cable.

Take the black negative cable from your trolling motor and connect it to the negative (-) terminal that’s still open on Battery 1.

3. Connect the red trolling motor cable.

Connect the red positive cable from your trolling motor to the positive (+) terminal that’s still open on Battery 2. The breaker or fuse should go on that positive lead from the motor side connection. Check your trolling motor manufacturer’s recommendations to make sure you’re using the right size.

4. Give everything a quick check.

At this point, the terminal of battery 1 that stays open is the negative side going to the motor, and the terminal of battery 2 that stays open is the positive side going to the motor. If you need a simple wiring diagram, this is the basic series layout.

5. Make sure you’re getting 24V.

Before you turn the trolling motor on, use a multimeter to check the voltage across the two terminals connected to the motor. You should see a reading around 24V.

If you do, take one last look to make sure the positive and negative cables are connected where they should be. Double-check polarity before powering on so you don’t damage the motor. Then you’re ready to power up the trolling motor.

A Few Safety Tips Before You Go

You don’t need to make this complicated, but there are a few things worth checking before you hit the water.

Keep your battery terminals clean and your connections tight. Things can loosen up from vibration, so it’s a good idea to check them every now and then.

Keep your wiring away from sharp edges, hot areas, and moving parts, and use loom or conduit where it makes sense for protection. Make sure the batteries themselves are secured so they can’t slide around in the boat and are sitting in a ventilated compartment.

If you’re using flooded lead-acid batteries, they need ventilation while charging. Follow the battery manufacturer’s instructions for your specific setup to help reduce sparks and battery explosion risk.

It also helps to label Battery 1 and Battery 2 and mark your positive and negative connections. That makes it much easier to see what goes where if you ever need to check the setup again.

Common Mistakes to Avoid

Before you turn everything on, watch out for a few easy mistakes:

• Mixing batteries that don’t match
• Connecting the positive and negative cables to the wrong terminals
• Using wire or battery cable that’s too small
• Using the wrong size circuit breaker or fuse
• Leaving connections loose or corroded
• Letting wires rub against sharp edges or hot parts
• Creating sparks or using an open flame around charging lead-acid batteries
• Reaching near the propeller area or reconnecting power while you’re still working on the setup

Charging Your 24V Battery Setup

Once everything’s wired, there’s another big question: how do you charge it? Really, that depends on the type of 24V battery setup you’re using.

If you have one 24V battery, use a charger that matches its voltage and battery type. A 24V lithium battery, for example, needs a charger made for that type of lithium battery.

If you have two 12V batteries wired in series, check the battery manufacturer’s charging instructions. Depending on the batteries, you may be able to use a compatible multi-bank charger that charges each 12V battery individually.

For Ionic lithium batteries, most 12V deep-cycle models over 12Ah that are wired in series should be charged individually at 12V. So don’t assume that just because your two batteries create a 24V system, you should automatically use a 24V charger.

Whatever setup you choose, make sure your charger matches your battery type. Lead-acid, AGM, and LiFePO4 batteries all have different charging requirements.

Battery Maintenance Tips

Your trolling motor batteries don’t need a ton of attention, but a little routine maintenance can go a long way:

• Recharge batteries according to the manufacturer’s recommendations after use.
• Check water levels regularly if you use flooded lead-acid batteries.
• Inspect terminals, cables, and connections for corrosion or damage.
• Make sure your charger works with your battery voltage and type.
• Follow the battery manufacturer’s recommendations for off-season storage.

If you notice a battery swelling, overheating, losing capacity quickly, or struggling to hold a charge, stop using it and check the system.

With a two-battery series setup, you want the batteries to stay pretty closely matched. If one reaches the end of its life, it may make sense to replace both.

When Lithium Batteries Make Sense

If you spend long days on the water or simply want to take some weight out of the boat, lithium can be a worthwhile upgrade for your trolling motor setup.

Here’s why more boaters make the switch:

• Less weight: LiFePO4 batteries weigh significantly less than comparable lead-acid batteries. That can make a noticeable difference when you’re already carrying fishing gear, fuel, and everything else that comes along for the day.
• More usable capacity: You can use more of a lithium battery’s capacity before it needs to be recharged. That means more of the battery’s stored power is actually available to your trolling motor.
• Consistent performance: Lithium batteries hold their voltage better as they discharge, which helps your trolling motor keep delivering steady power throughout the day.
• Longer battery life: Quality LiFePO4 batteries can provide thousands of charge cycles, so they can last much longer than traditional lead-acid batteries.
• Faster charging: Lithium batteries can also recharge much faster with a compatible charger, which is especially helpful if you’re fishing several days in a row.

And with a 24V trolling motor, lithium gives you another option. Instead of wiring two 12V batteries together, you can use a single 24V lithium trolling motor battery and keep the setup simpler.

Upgrade Your 24V Trolling Motor Setup With Ionic Lithium

If you want to build a 24V trolling motor battery setup with Ionic LiFePO4 batteries, you’ve got a couple of ways to do it.

You can wire two matching 12V Ionic batteries in series, just like we covered above. Or, if you’d rather have fewer batteries and connections to deal with, you can use a single 24V Ionic lithium battery made for 24V trolling motors.

Either way, you get some major advantages over other batteries, especially lead-acid:

• Much less weight: Ionic lithium batteries can weigh up to 70% less than comparable lead-acid batteries.
• More usable energy: Ionic deep-cycle batteries let you use more of the battery’s capacity before you need to recharge.
• Thousands of cycles: Ionic deep-cycle batteries are rated for thousands of partial charge cycles for years of use. Expect 3,000 – 5,000 partial cycles with Ionic.
• Built-in BMS protection: The Battery Management System helps protect the battery from things like too much or too little voltage, too much current, and extreme temperatures.
• Bluetooth monitoring: Check battery charge, voltage, current, temperature, and other information right from the Ionic app.
• 11-year warranty: Ionic trolling motor batteries are backed by LithiumHub’s 11-year battery warranty.

For a 24V setup, you can use two 12V 60Ah Ionic batteries wired in series. If you need more runtime, two 12V 100Ah batteries are another option.

You can also go with a single 24V 50Ah Ionic battery if you’d rather keep the setup simple and avoid wiring two batteries together.

Which option makes the most sense really comes down to how long you’re usually on the water, how much space you have, and whether you prefer one battery or two. Either way, Ionic lithium can help cut down on weight while giving you plenty of usable power for your trolling motor! And don’t forget, if you have questions, it’s really easy to get in touch with us. Just click here or give us a call.

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