Can you overcharge or undercharge a marine battery?
Marine batteries need to be properly charged to last. Always use a charger that meets your boat battery manufacturer’s recommendations.
For lead acid batteries, regularly undercharging your boat battery will lead to ‘sulfation’: sulphate crystals forming on the plates, reducing the battery’s ability to charge and negatively impacting battery performance.
Excessive overcharging is also damaging to boat batteries (especially AGM and gel batteries), ‘cooking’ the battery and leading to corrosion and faster discharges. Make sure to follow the manufacturer's charging recommendations to avoid overcharging.
The best way to preserve your marine battery’s charge is to invest in a multistage charger like SmartCharge.
How do I maintain my marine battery?
Marine batteries need to be kept clean, charged and topped up with water, if required.
Batteries that aren’t kept charged can freeze in cold temperatures and experience cracked cases. Use a maintenance charger like SmartCharge to keep it charged when not in use.
Regularly inspect your battery’s external components, checking that the lead posts don’t show signs of coming off and that there are no signs of corrosion on exposed metal terminals. At least once a year, you should clean out the battery box, check for signs of leaks, inspect the tie-downs, and check that the vent is clear.
Water loss is a common maintenance issue in wet-cell marine batteries, with deep-cycle batteries losing water faster than starters. Water loss often occurs in batteries from evaporation due to heat and other chemical reactions and can rapidly shorten your battery’s life. If you have a maintainable battery, top up your battery’s water level with distilled water: tap water contains impurities that will accumulate inside the battery and cause issues. Make sure not to overflow the water level.
How do I jumpstart my boat battery?
Jumpstarting a marine battery is very similar to jumpstarting a car battery. The main difference is that you need to ensure there is plenty of ventilation before connecting the battery: make sure to avoid fuel fumes.
After turning off all electrical appliances that use your boat’s battery, use a reliable jump-starter like the IS-1500. Attach the red clamp on the positive terminal, then the black clamp on the negative terminal. Check the display on IS-1500 and once displaying a green light, start the engine. Once the motor is running, disconnect the jump-starter.
If jumpstarting your marine battery yourself doesn’t work, it’s time to call RACV Marine.