Tips to Help Your Marine Battery Sail through the Winter Season

One of the best ways to start off the next boating season smoothly is to practice some simple maintenance steps on your boat’s battery during the winter months. Review these tips to help preserve battery life and enhance performance. As always, be sure to follow the manufacturer’s guidelines for battery care and handling and direct all questions to a battery professional.

Verify your Battery Type to Determine the Kind of Maintenance Needed

If you own a flooded lead acid battery, it is essential to check the electrolyte level periodically. This is done by removing the caps. Use a flashlight (if necessary) to see inside the battery. If needed, add water until the electrolyte level just covers the top of the plates, or per the manufacturer’s instructions.

However, if you own an Absorbed Glass Mat (AGM) battery, such as any of the ODYSSEY® Marine Dual Purpose batteries, you can leave the maintenance behind. These non-spillable batteries are sealed and never require water replenishment, making them maintenance-free.

Inspect your Battery’s Condition

Inspect the battery connections and cables to make sure they are clean, without corrosion and undamaged. Tighten any loose connections. Check the battery case for cracks—and flooded lead acid batteries for leaks. Make sure that there is a protective boot over the positive battery terminal. The boot prevents a short from occurring.

Clean the Battery

Remove any corrosion from battery terminals and cable connectors. A brass wire brush or terminal cleaning tool and a small amount of baking soda work well. Periodically clean dirt and grime off the top of your battery as excessive build up can cause a battery to self-discharge.

Check Battery State of Charge

A digital voltmeter will help you determine the battery’s State of Charge (SOC). Allow the battery to rest at least 12 hours before using the device to obtain a more accurate reading. Place the probes on the terminals to obtain a reading. Generally charging parameters to follow include:

  • 9 Volts – 100 percent charged
  • 2 Volts – 50 percent charged
  • 5 Volts – 0 percent charged


While the battery in your motor vehicle is recharged by the alternator every time you start the engine, your marine battery may be dormant for long periods of time. By keeping your battery properly charged, you can maximize battery life and performance. Flooded lead acid batteries may lose up to 5 percent of their charge per month if left idle. However, overcharging or undercharging a marine battery could reduce battery lifespan.

Proper charging amperage is very important. For example, for ODYSSEY® marine batteries featuring Thin Plate Pure Lead (TPPL) technology, requirements are as follows:

  • Minimum recommended: 10 percent of the amp hour capacity
  • Optimum recommended: 40 percent of the amp hour capacity
  • Maximum recommended: 100 percent of the amp hour capacity

Using a marine battery charger with an AGM setting can help accurately charge ODYSSEY® batteries.

Consider if a Battery Upgrade is in Order

While battery maintenance is important, remember that a rugged, dependable, long-lasting battery – one that requires less physical labor – can save time and effort. It makes sense to consider a high-quality sealed AGM battery, such as ODYSSEY® Marine Dual Purpose batteries. These batteries offer the combined advantages of high cranking power, deep cycling capability (up to 70 percent longer than conventional deep cycle batteries), plus rugged resistance to impact, vibration and extreme temperature. ODYSSEY® marine batteries are backed with an industry-leading warranty for trusted performance for all your boating power demands.

Battery maintenance may not be the way you would choose to spend your spare time, especially during the cold, winter weather, but when boating season opens, it will help ensure smooth sailing ahead.

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EnerSys, the global leader in stored energy solutions for industrial applications, designs, manufactures and distributes energy systems solutions and motive power batteries, specialty batteries, battery chargers, power equipment, battery accessories and outdoor equipment enclosure solutions to customers worldwide. The company goes to market through four lines of business: Energy Systems, Motive Power, Specialty and New Ventures. Energy Systems, which combine power conversion, power distribution, energy storage, and enclosures, are used in the telecommunication, broadband and utility industries, uninterruptible power supplies, and numerous applications requiring stored energy solutions. Motive power batteries and chargers are utilized in electric forklift trucks and other industrial electric powered vehicles. Specialty batteries are used in aerospace and defense applications, large over-the-road trucks, premium automotive, medical and security systems applications. New Ventures provides energy storage and management systems for various applications including demand charge reduction, utility back-up power, and dynamic fast charging for electric vehicles. EnerSys also provides aftermarket and customer support services to its customers in over 100 countries through its sales and manufacturing locations around the world. More information regarding EnerSys can be found at


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