Neglecting your boat batteries during the winter months can lead to disappointments for many anglers who do not fish during the winter season. Even for those anglers who continue to fish during the winter months, cold weather can take a toll on your boat’s batteries if they are not properly maintained.

There are three broad types of marine batteries available for boaters; each has its own application, and boat operators need to understand how each works and what maintenance is required to ensure you get good battery life and optimum performance. The three broad types of batteries are cranking, deep-cycle and dual-purpose.

Within that broad definition of battery types as it relates to how it is used on your boat, you have three specific battery types based on their internal construction, and that can also impact their performance and maintenance requirements.

Those specific battery types are FLOODED (lead acid), AGM (absorbed glass mat) and GEL cell (gelled electrolyte lead acid). The most common type of battery used for marine purposes is the FLOODED or lead acid battery, which is used for making cranking and starting batteries.

The cranking battery is often referred to as the starting battery and is designed for initial cranking of the boat’s outboard or inboard motor. Only a small amount of the cranking battery’s capacity is used for starting the boat’s motor. The motor’s alternator then recharges the battery, but when boat accessories are also attached to the cranking battery and the boat is not run very often the battery’s charge can be depleted.

The second type of marine battery is the deep-cycle battery. A deep-cycle battery requires a low amount of current or power over a long period of use. A deep-cycle battery can be used until it is completely discharged and it can be repeatedly recharged with little if any loss of capacity.

However, the deep-cycle battery must be recharged after each use to maintain its performance and provide for extended life. Leaving a deep-cycle battery in a discharged state especially over the cold winter months will ensure it will have a short operating life.

Unless the cranking and deep-cycle batteries are maintenance-free, you will need to periodically check the electrolyte level in the battery. When adding water to the battery, only use distilled water to provide longer battery life. The water level should always be maintained above the battery’s plates but below the battery’s vent caps.

The third type of battery is the popular dual-purpose battery. This battery is suitable for both cranking and deep-cycle operations. These batteries are usually maintenance-free and there is no need to periodically check the electrolyte level. However, the dual-purpose battery must be kept fully charged just like the other two types of batteries if you want to receive maximum performance and battery life.

Now let us look at on-board battery chargers and considerations you need to make when purchasing those type chargers. First, make sure that the on-board battery charger will charge the type of battery that you have. Most on-board battery chargers are safe to use on most marine batteries.

Second, you need to know the size of the batteries that you intend to charge with the on-board battery charger. Many cranking batteries are around 75-amp hours and many deep-cycle batteries are more than 100-amp hours. On-board battery chargers come in different sizes based on amperage and that is extremely important when considering the size charger you need for your application.

Also important is whether the on-board battery charger is a transfer-on-demand charger that will transfer all the available charging amps to where it is required or the older and more typical on-board chargers that divide the charging amps between the number of batteries and is unable to transfer any available or extra amps to where it is required.

An example would be using a transfer-on-demand 10-amp charger to charge two batteries. Once one of the two batteries becomes fully charged, the charger will transfer the full 10-amps to the other battery until it is fully charged. Charging those same two batteries with a conventional 10-amp on-board charger can only give each battery 5-amps at any time and will likely take longer to complete charging.   

On-board battery chargers come with from one to as many as four banks with each bank capable of charging a single battery. The best rule is to purchase the right size on-board battery charger for your specific need and make sure the charger is a “Smart Charger” which is microprocessor controlled and that it is a transfer-on-demand type charger.

Make sure the charger is waterproof and do not allow costs to dictate your choice. A low-end charger may save you money but it likely will fail to meet your needs.

Good fishing and see you next week.