Sea Ray Battery Maintenance 101

Learning how to care for your boat’s battery bank will not only save money but will also help to make sure you can get home after a great day on the water.

Published on February 9, 2022


Don’t Run Your Battery Down
Boats typically have starting batteries to get the engine running and deep-cycle house batteries to power items like the stereo while at the sandbar. The biggest difference is deep-cycle batteries are designed to be discharged and then recharged many times while starting batteries are not. Although standard lead/acid deep-cycle batteries and absorbed glass mat (AGM) deep-cycle batteries are designed to power items even when the engine is off, to increase their longevity, it’s important not to let the depth of discharge (DOD) reach more than 50% regularly. The deeper and more often they are drained past the 50% level, the quicker they age. More expensive lithium-ion batteries are built to withstand heavy depletion without adverse effects.

Lead/acid batteries should be checked monthly to make sure the liquid electrolyte solution is full. If not, add distilled water to the fill level. Gel, AGM and lithium-ion batteries are sealed and require no such maintenance.     

Keep Boat Batteries Charged
The biggest key to prolonging battery life on your boat is to keep them fully charged. After every outing when you have run power-hungry items like that killer stereo system complete with subwoofer for prolonged periods, it’s important to recharge the house batteries or at least test them when you get back in. Starting batteries usually receive enough recharging from the engine’s alternator, though it’s still prudent to routinely check them and charge as needed.

An inexpensive investment called a multimeter can be purchased at places like Harbor Freight for around $7 and it can be used to quickly test the voltage of your batteries. A healthy, fully-charged battery will register 12.6 or more volts. A battery that registers 12.1V–12.4V might seem like it’s “close enough for government work” but in reality, it is in danger of prematurely aging and should be charged. Batteries that register 12.0V or less are considered fully depleted and need immediate charging. Many Sea Ray boats come with a built-in battery charger, which makes the process safe and painless. If your boat doesn’t have one, it can be easily added by DIY-savvy boaters or local dealers. While lead/acid batteries are more tolerant of over-charging, gel and AGM are not and overcharging a lithium-ion battery can cause a fire. 

Batteries can experience a phantom drain even when everything is shut off so they should be removed during long periods of disuse like in winter and stored on a piece of wood in a place like a garage. Periodically, test and trickle-charge charge them as needed.     

Keep Your Boat’s Battery Clean
One of the important parts of boat battery care is keeping the poles and cable connectors clean and free of corrosion. Periodically, remove the cables by taking off the negative side first (usually the cable is black with a “–” indicator on the battery). Then remove the positive cable (typically red with a “+” symbol on the battery). To remove any build-up, use a product like CRC Battery Cleaner with Acid Indicator. After brushing the terminals and connectors with a battery cleaning tool, spray it on and if the yellow foam turns pink it means there is acid present, signaling leakage, which is immediately neutralized. If there’s more than a small amount of pink, the battery should be checked by professionals. If not, rinse with water, dry and reconnect the cables, starting with the positive side first then the negative. A teaspoon of baking soda mixed with a glass of water makes a good cleaner also and neutralizes acid.

To avoid hearing that awful clicking sound when you turn your boat’s key, performing a few simple maintenance tasks will make sure when it’s time to head home there are no surprises.


This is for general information purposes only. Your use or reliance on any of the information in this Blog is solely at your own risk. Under no circumstance will we have any liability for any loss or damage of any kind incurred as a result of the use of any of the information provided.

Options and features mentioned subject to change. Please confirm availability of all accessories and equipment with an authorized Sea Ray dealer.


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