Spring has sprung, and you’re ready to get out on the water! Long before that first weekend trip, spend some time recommissioning your craft. That should include a thorough check of each marine battery.
Before you go, check that boat battery!
For a great day on the water, follow these four steps to avoid being stranded.
Spring has sprung, and you’re ready to get out on the water! Long before that first weekend trip, spend some time recommissioning your craft. That should include a thorough check of each marine battery - the heart of your boat’s electrical system and critical to a successful maiden season voyage.
STEP 1 - Visual Inspection
Inspect your battery and terminals for damage. If either is cracked, replace the battery.
Look closely at the cable connections and terminal posts. The connections on your terminals must be clean and corrosion free to get the most power. Poor connections increase electrical resistance and cause voltage to drop, which means some of your devices, including your starter, may not get the power needed to operate. Inspect the battery cables for damage, excessive corrosion, or fraying, and replace if needed. Over the winter, the terminals or terminal cables might have grown a layer of corrosion, which is a white or blue-green powder. If so, proceed to STEP 2.
STEP 2 - Cleaning
Before cleaning, disconnect the battery terminals. It’s always a good idea to wear protective gloves and eyewear when working around batteries.
Using a paste of three parts baking soda and one part water, scrub your terminals with a battery terminal brush. Do the same thing to the battery cables. Rinse all the parts thoroughly with clean water. Dry the battery before reconnecting it. Coat the terminals with grease, petroleum jelly, or anti-corrosion spray to prevent corrosion from reoccurring,
It’s also important to remove any grease and grime from the battery case with a good household detergent before rinsing thoroughly.
STEP 3 - Test Charge the Battery
The ultimate test: how does the battery perform?
To test a free-standing battery, charge it for 12-24 hours with a smart charger system. Then, let the battery sit for 12 hours with no connected cables (to ensure no trickle drainage) so you don’t get a false surface charge reading.
Next, using a digital multimeter set to the 20v range, place the red lead on the positive terminal first, then the black lead on the negative terminal. Compare your readings to the scale below:
12.65 to 12.77 volts – 100% charged
12.45 to 12.54 volts - 75% charged
12.24 to 12.29 volts - 50% charged
11.99 to 12.06 volts - 25% charged
11.75 to 11.89 volts - your battery is essentially dead!
If you get anything less than a full charge reading, test your battery again using the above steps. You should consider replacing a battery that is less than 75% charged.
The most accurate reading of a battery’s health is to test it under load. Install the battery in your boat after a full charge. Place the multimeter leads across the battery, and while a helper cranks the engine, take a test reading. If the battery voltage drops below 9.6 volts, your battery is on the way out and should be replaced.
Taking the time well beforehand to ensure your battery is in tip-top shape will help make your boating adventures safe and fun this season!