When Recommissioning Your Motorboat, Keep Battery Performance in Mind

Recommissioning the boat for open waters requires numerous tasks involving all parts and systems of the boat, including the battery. Successful recommissioning without purchasing new batteries will depend a lot on the batteries you choose, as well as how they were decommissioned.

Boat owners have found that an Absorbed Glass Mat (AGM) battery recovers well from deep discharge. This makes it more tolerant of storage abuses than conventional flooded lead acid batteries.

AGM batteries that feature advanced Thin Plate Pure Lead (TPPL) technology, such as the ODYSSEY® Marine Dual Purpose battery, can offer operators premium dual-purpose performance. These batteries can cycle and start engines without compromising their life expectancy or power, and they are also virtually maintenance-free, with no watering or changing required.

The Importance of Proper Battery Storage Procedures

It is important to maintain the battery at or near full charge while in use to ensure proper operation through its entire intended service life. What happens between decommissioning and recommissioning a motorboat will affect the battery’s condition and thus its expected life. Fully charging the battery before storing it is recommended to prevent the buildup of sulfation, which can accumulate to a point where the battery will stop working. A fully charged battery will help limit drainage from parasitic loads that onboard electronic devices and accessories can create if the engine is inactive for an extended time. Damage from excessive discharge can be prevented by connecting the battery to a trickle charger after being decommissioned. The best practice to prevent excessive discharge while inactive is to disconnect the negative battery cables or use the battery disconnect switch to ensure that no devices are wired directly to the battery. Please refer to your owner’s manual or consult a battery professional for more details about decommissioning your specific craft.

Each type of battery is charged differently, so consult the manufacturer’s recommendations or a battery professional before charging. ODYSSEY® Marine Dual Purpose batteries can be brought back from 20 percent State of Charge (SOC) to better than a 90-percent SOC in about an hour with a charge of approximately 300 amps for a 100 amp-hour battery. A TPPL battery does not require a limit on the current, as long as the charge voltage does not exceed 15 volts.

In addition to fully charging the battery, the temperature of the environment in which the battery is stored should be considered. If the temperature gets low enough, the electrolyte in an acid-filled battery may freeze. On the other hand, the lower the temperature, the longer the available storage time due to reduced leakage current, as long as the temperature does not drop below the manufacturer’s specifications.

An ODYSSEY® Marine Dual Purpose battery can be stored for two years, or until the Open Circuit Voltage (OCV) drops to 12 volts, at a temperature of 77°F (25°C) or as low as -40°F (-40°C). They are also extremely resistant to shock and vibration and can perform in the harshest environments.

Battery Testing

Before recommissioning, it’s possible to determine a battery’s SOC through testing. An accurate digital voltmeter will measure the disconnected battery’s OCV. The battery manufacturer’s specifications will indicate what OCV will correspond to 100 percent SOC. Wait at least six to eight hours after charging the battery to measure the OCV. This will allow enough time to ensure that chemical reactions inside of the battery have reached a state of equilibrium.

Another test to determine the condition and capabilities of a battery is a CCA test. When a fully charged battery at room temperature (72°F [22°C] to 80°F [27°C]) is load tested at half its Cold Cranking Amps (CCA) rating, it is known as the half-CCA method. If the terminal voltage is at least 9.6 volts for a 12-volt battery after 15 seconds, the battery is considered to be in good condition.


If the battery was stored at only partial charge, or if it has reached its expected life, it may be necessary to replace it. The following guidelines are for the replacement of the battery when it will not recharge:

  • Disconnect all cables from the battery and take it to a battery recycling exchange center
  • Replace any deteriorated cables and components damaged by corrosion and acid
  • Set the replacement battery in the holder and secure it in place
  • Connect the positive cable to the positive terminal and the negative cable to the negative terminal
  • Tighten the bolt, screw or nut to its appropriate battery specifications
  • Always be sure to follow the manufacturer’s guidelines for battery care and handling, and direct any questions to your battery professional.


Using ODYSSEY® Marine Dual Purpose batteries for your boat will ensure reliable performance for staring and trolling while powering the boat’s onboard accessories. The TPPL technology built in simplifies recommissioning and decommissioning at the beginning and end of each season. With the proper charging, storage, installation and use, the ODYSSEY® Marine Dual Purpose battery will provide unmatched long life and dependable service.



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