Years ago a wise old engineer at one of the major manufacturers once said, “Boat batteries don’t die. They’re murdered.”
Today’s marine batteries are as tough as nails, in many respects, but to get the longest life and best performance out of them (and thus the most for the money you spent on your batteries), you must invest some time in proper care and maintenance.
These 5 tips will help you remain innocent of assaulting a battery.
Avoid Overheating — Excess heat can cause the lead plates within the cells to buckle and shed active material. Never charge a battery when its temperature is above 120° Fahrenheit.
Curb Excessive Gassing — If the conversion of lead sulfate to lead and lead peroxide cannot keep pace with the current, during the charging process, the excess current causes the water and electrolyte molecules to split into gaseous hydrogen and oxygen. In simple terms, the water and electrolyte boil off.
Never Overcharge —Applying current to a fully charged battery will cause gassing as well as oxidation of the positive plate and internal resistance to the battery. Overcharging can also create excess heat that may further damage the plates.
Minimize Vibration — Internal plates can become damaged when a battery is subjected to severe shock and vibration, which may reduce the battery’s capacity and shorten its working life. Notice that battery storage compartments on most large bass and multi-species boats is somewhere in the rear half of the hull where there’s less vibration and shock due to bow-slap is minimized. Still, make sure all batteries are securely tied down in the battery tray or box.
Use Distilled Water—Many marine batteries are sealed and maintenance-free. But if yours is a wet-cell, lead-acid battery, check the liquid level in each cell regularly. Never let the liquid level fall below the tops of the plates as the as the exposed area will corrode in the presence of air. Top the cells off to the proper fill-level, when necessary, only with pure distilled water. The minerals in tap water, softened water, or even well water could damage the plates and reduce the performance and life of the battery.
Each deep-cycle battery is good for a finite number of cycles (full discharge and recharge). If you want to get every last one of them, take care of your batteries.