How to Replace a Boat Battery

A battery is crucial to starting and running your boat, and a dead battery could keep your boat from getting out on the water. The alternator charges the battery while the engine is running, but if your boat’s battery is failing, it may not hold a charge and can fail to start the next time. If your boat won’t start or is making a clicking sound and not turning over, your battery could be bad or you may have an issue with other starting and charging components. Help ensure you have a great day on your boat by getting your battery tested for free at O’Reilly Auto Parts before hitting the water. If you need to replace the battery in your boat, check out this video and step-by-step instructions to remove and replace your boat’s battery.


Tools & Materials

safety glasses Safety Glasses
Protective Gloves Nitrile Gloves
Shop Towels Shop Towels
Ratchet Tool Set Ratchet & Sockets
Marine Super Start Battery Marine Battery

Step-by-Step Instructions for Boat Battery Installation

We'll be changing the starting battery on a 2003 Sundancer Pontoon, but procedures will vary from one boat to the next, so be sure to know the specifics for your boat before getting started. If you’re not completely comfortable doing this yourself, we’d be happy to recommend a professional technician in your area.
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Remove the Old Boat Battery

Remove the battery hold down

Step 1: Locate the Boat Battery and Remove the Hold-Down

First, locate the battery on your boat. In our case, the battery is located in the back of our boat. Your battery may be located in a compartment that you may need to open to access the battery. Once located, remove the battery hold-down to access the battery.



Do It Right: Also, your battery may have an ON/OFF switch. Make sure the switch is turned OFF until you install the new battery.

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Remove any battery corrosion

Step 2: Check and Remove Battery Corrosion

Check your terminals for corrosion. Use terminal spray and a rag to remove any corrosion you may find.
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Remove the negative and positive cables

Step 3: Remove the Battery Cables

Now remove the cables from the battery posts, starting with the negative cable. Set it aside someplace safe where it can’t touch metal. After the negative cable is removed, remove the positive cable and set it aside.
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Remove the old battery

Step 4: Remove the Old Boat Battery

Once you are sure all cables are out of the way, carefully lift the old battery out of the housing. If needed, remove the battery terminals and set them aside. Depending on the new battery, you may need to reinstall them them before reattaching the cables.
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Install the New Boat Battery

Mechanic placing a new Super Start Marine Battery into the battery housing

Step 5: Install the New Boat Battery

Install the new battery. Make sure the new battery’s posts are in the right orientation and lower it in place. Make sure it is seated securely.

Do It Right: Installing the correct battery allowed us to properly route the cables.

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Man using a ratchet to secure the bolts to the negative and positive battery cables

Step 6: Reattach the Battery Cables

Reattach the two cables, starting with the positive cable then the negative cable.
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Battery hold-down being secured in place

Step 7: Reinstall the Lid and Hold-Down

Reinstall the lid and hold-down if necessary and make sure it is secure. If you had to access your battery through a compartment, make sure the cables are secure inside, then close the lid. If your battery had an ON/OFF switch, switch it to the ON position.
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Man pressing a switch above the radio to test if the battery is connected properly

Step 8: Test the Battery

Switch on an electronic device to test the battery. If the device works, the battery is properly connected.

Do It Right: Since your boat is likely to go long periods of time without being started, keep a battery maintainer on-hand and connected during stretches or inactivity so it is ready to go when you are.

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Additional Resources

How to Get Your Boat Ready for Summer

How to Get Your Boat Ready for Summer
How to Change a Jet Ski Battery

How to Install a Jet Ski Battery
man fishing on boat in the water in colder temps

How to Winterize Your Boat

Replacing a faulty or failing boat battery can save you from a disappointing day on the water. Signs that the battery in your boat is reaching the end of its service life include hearing a clicking sound but the engine failing to turn over, or if your boat will not start at all and is silent when the ignition is engaged. Find a wide selection of replacement parts and components you need to repair or maintain your boat at O’Reilly Auto Parts, including deep cycle marine batteries, boat accessories, covers, and more.

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The automotive repair work depicted in this series is performed under the direction of the manufacturer of the product featured. Prior to undertaking any of the demonstrated repairs on your vehicle, we suggest you consult with a certified mechanic or another professional who can adequately advise you of the proper repair or remedy required. O’Reilly Automotive Stores, Inc. and its affiliates (“O’Reilly”) disclaims any responsibility for injury or damage resulting from a viewer’s attempt to recreate the repairs shown in this series.