Can You Use a Car Battery for a Trolling Motor?

Yes, you can use a car battery for a trolling motor in some situations, but it is not the best choice.

If you have a 12-volt trolling motor and a 12-volt car battery, the battery can usually power the motor. The problem is that car batteries and trolling motor batteries are built for different jobs.

A car battery is made to give a large burst of power for a few seconds to start an engine. A trolling motor needs steady power for a much longer time.

If you plan to use your trolling motor regularly, a deep-cycle marine battery is the better choice.

Why a Car Battery Isn't the Best Choice

Think about what happens when you start your truck or car. The battery sends a lot of power to the starter for a short time. Once the engine is running, the alternator takes over and charges the battery again.

A trolling motor works differently.

It may run for hours while you're fishing, moving along a shoreline, holding your boat in place, or slowly working your way across a lake.

That means the battery gets drained much farther than a normal car battery is designed to handle.

Using a car battery once in a pinch probably isn't going to ruin everything. But draining it deeply over and over can shorten the life of the battery.

Car Battery vs. Deep-Cycle Marine Battery

The biggest difference is how the batteries are meant to be used.

Car batteries are made for starting engines.

They provide a quick burst of power and are normally kept close to a full charge.

Deep-cycle batteries are made for longer use.

They are designed to provide power over a longer period and handle repeated charging and discharging much better.

That's why deep-cycle batteries are commonly used for trolling motors, RVs, campers, golf carts, and other equipment that needs steady battery power.

Minn Kota recommends using a 12-volt deep-cycle marine battery for its trolling motors. For better run time, the company recommends looking at the battery's amp-hour rating as well.

Can You Use a Car Battery in an Emergency?

If your trolling motor battery dies and a car battery is the only battery you have available, it may work as a temporary option.

There are a few things to check first.

The voltage needs to match your trolling motor system. A normal car battery is 12 volts, so it should only be used as part of a setup that matches the voltage requirements of your motor.

You also don't want to drain the battery too far.

If that same battery needs to start an engine later, you could end up with enough power to run the trolling motor but not enough power left to start the engine.

For a day on the lake, that is not a situation you want to find yourself in.

What Battery Should You Use for a Trolling Motor?

For most trolling motors, a deep-cycle marine battery is the right choice.

These batteries are built to handle the steady electrical draw that a trolling motor puts on them.

When shopping for a battery, check:

• Battery voltage
• Amp-hour rating
• Battery size
• Battery type
• Your trolling motor manufacturer's recommendations

For many 12-volt Minn Kota trolling motors, Minn Kota recommends a deep-cycle marine battery with at least 110 amp-hours for the best results. Higher amp-hour capacity generally means more available run time.

That doesn't mean every boat needs the same battery. The right setup depends on your trolling motor, boat, how you fish, and how long you normally stay on the water.

What About 24-Volt and 36-Volt Trolling Motors?

Larger trolling motors often use 24-volt or 36-volt systems.

A 24-volt trolling motor normally uses two 12-volt batteries wired together in series.

A 36-volt trolling motor normally uses three 12-volt batteries wired in series.

Minn Kota recommends using batteries that match in type, size, and age when they are being used together in these systems.

Don't simply hook up extra batteries without knowing how your trolling motor needs to be wired. Incorrect battery wiring can damage equipment and create a safety risk.

If you're unsure about the setup, having someone familiar with marine electrical systems look at it is worth the trouble.

Will a Car Battery Damage a Trolling Motor?

Using a 12-volt car battery on a compatible 12-volt trolling motor does not automatically mean the motor will be damaged.

The bigger concern is the battery.

A starting battery isn't designed to be repeatedly drained the way a trolling motor can drain it. You may notice shorter run times, weaker performance as the battery loses charge, and a shorter battery life.

There is also another reason to keep your trolling motor battery separate from your starting battery.

If your trolling motor drains the battery that starts your boat's main engine, you may not have enough power left to get the engine running. Minn Kota recommends using separate deep-cycle batteries for the trolling motor instead of relying on the engine's starting battery.

How Long Will a Battery Run a Trolling Motor?

There isn't one answer because run time depends on several things.

A trolling motor running at full power uses much more electricity than one running at a low speed.

Boat weight matters too. Wind, waves, weeds, current, motor size, battery condition, and how often you use the motor can all change how long a battery lasts.

The amp-hour rating gives you a useful way to compare batteries. In general, a battery with more amp-hours can supply power longer than a similar battery with a lower rating.

Still, don't expect the number printed on the battery to tell you exactly how many hours you'll get on the lake. Real-world use changes constantly.

A Few Ways to Get More Life From Your Trolling Motor Battery

A good battery isn't much help if it isn't taken care of.

Charge your battery after you use it instead of leaving it partly discharged for days or weeks.

Keep the battery connections clean and tight.

Make sure you're using the correct charger for your battery type.

Check your trolling motor prop for fishing line and weeds. Anything that makes the motor work harder can use more battery power.

It's also a good idea to check the battery before the start of fishing season, especially after a long Minnesota winter.

So, Can You Use a Car Battery for a Trolling Motor?

Yes, a car battery can power some trolling motors if the voltage is correct.

But for regular use, we wouldn't recommend it.

A deep-cycle marine battery is made for the long, steady power draw of a trolling motor and will usually give you a much better setup for a day of fishing.

A car battery is better left doing what it was built to do: starting your vehicle.

If you're having trouble with your trolling motor, battery setup, wiring, or marine electrical system, stop by Channel Marine & Sports in Richmond, MN. We're located in Central Minnesota near the Sauk River Chain of Lakes and work with boats, motors, docks, lifts, and Minn Kota trolling motors.

Getting the battery and trolling motor setup right before you hit the water can save you a lot of frustration once you're out on the lake.