Blog, 25th Anniversary

Tips for Properly Storing Your Marine Battery During the Off-season

As fall approaches, and boating enthusiasts bid farewell to the open waters for a few months, it’s important that your vessel is properly stored. This also applies to the subsystems of the vessel including the battery. To ensure a smooth start-up next season, follow some simple tips to winterize and store your marine battery. Always be sure to follow the manufacturer’s guidelines for battery care and handling and direct any questions to your battery professional.

  1. Perform end-of-season maintenance. Inspect cables, connections and the battery case. Remove any dirt or corrosion on the battery terminals. If you’re using a conventional lead acid battery, then make sure to water it properly. Measurement is key; avoid overwatering or underwatering. Fill to the specified level by the battery manufacturer.
  2. Give the battery a final charge. There are two reasons for this. First, it will help ensure the life and capacity of the battery. Second, maintaining a full charge will help keep the battery from freezing in cold winter temperatures.
  3. Check State of Charge (SOC). On a conventional flooded lead acid battery, check each cell, with a hydrometer, to confirm a specific gravity of 1.265 ­– 1.285 or read the voltage with a voltmeter. A voltage of 12.6V indicates a fully charged flooded battery. An Absorbed Glass Mat (AGM) battery voltage would read 12.9V or higher when fully charged.
  4. Disconnect the battery cables. Leaving your battery in place with cables connected makes it susceptible to parasitic draw from any electronics that remain connected. While this may only represent a very small power draw, even a very low draw can drain the life of a battery in a relatively short period.
  5. Store the battery. It’s a good idea to remove the battery from the vessel and place it in a cool, dry location. Make sure it will not be exposed to freezing temperatures, which can damage the battery. If you are using a conventional lead acid battery, store it safely in a plastic bin or on a surface that will not react with acid should the battery leak or become damaged. If you will be maintenance charging the battery, make sure you have easy access to the battery.
  6. Maintenance charging. Consider using a trickle charger, or a smart charger, if you want to be sure that your battery doesn’t overcharge. Chargers aren’t universal so be sure to use the right charger and the right settings for your battery and type.

Virtually maintenance-free ODYSSEY® Marine Dual Purpose batteries are manufactured with a military inspired design and Thin Plate Pure Lead (TPPL) technology to offer slower self-discharge, less corrosion, faster recharging and better endurance in harsh environments. They are resistant to high-impact shock and vibration that can impact the longevity of a battery and can perform in extreme temperatures as low as -40°F (-40°C). They are designed to deliver twice the overall power and three times the life of conventional flooded lead acid batteries.

Come to think of it, maybe there’s one more tip that should be added to the top of the list. If your end goal is a smoother start to the boating season, consider upgrading the battery in your boat to an ODYSSEY® Marine Dual Purpose battery—that is, if you don’t already own one.

This year, EnerSys® marks 25 years of ODYSSEY® battery production. To follow the ODYSSEY® battery 25th Anniversary journey, visit our website at or connect with us on InstagramTwitter, and Facebook by using the hashtag #MYODYSSEY.


EnerSys, the global leader in stored energy solutions for industrial applications, 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. Energy Systems, which combine enclosures, power conversion, power distribution and energy storage, are used in the telecommunication, broadband and utility industries, uninterruptible power supplies and numerous applications. Motive power batteries and chargers are utilized in electric forklift trucks and other industrial electric powered vehicles requiring stored energy solutions. Specialty batteries are used in aerospace and defense applications, large over-the-road trucks, premium automotive, medical and security systems applications. EnerSys also provides aftermarket and customer support services to its customers in over 100 countries through its sales and manufacturing locations around the world. With the recent NorthStar acquisition, EnerSys has solidified its position as the market leader for premium Thin Plate Pure Lead batteries, which are sold across all three lines of business. More information regarding EnerSys can be found at