How often do you service your boat's marine batteries?

Yes, I deliberately used the word 'service' to catch your eye. Because chances are you might check your boat's engine oil levels. You probably monitor your boat's power steering fluid levels and the gear lubricant levels. You might check the belts for tension. You might even monitor salt and corrsion build-up on parts of the engine and clean and spray with anti-corrosio paint.

But how often do you think about checking your boat's batteries. They need some attention too, but are easy to forget about. After all, it's boat engines that are the big ticket items that we worry about having to replace. But given some basic and routine maintenance, marine batteries can enjoy an extended life and you can be rewarded with lower operating costs in not having to replace them earlier than otherwise required.

Basic maintenance for a marine battery involves observation more than anything. Most of the time you should not need to do much, or anything at all. But you should make it a priority to check your boat's batteries as part of your basic maintenance routine.

The terminals on a marine battery can oxidize the same as a car's. This means you need to check the battery terminals regularly for corrosion, especially if your boat doesn't get used often. Corrosion can appear as a build-up of white powdery deposits around either or both of the battery terminals. There can also be a bit of color mixed in - a bluish-green tint. These deposits can be the result of chemical exchanges involving vapors and the battery terminal.

Directions for inspecting and cleaning you boat's marine batteries:

1. Remove the battery box cover/s. Disconnect the battery cables from the battery terminals by loosening the nut on each cable clamp. Once they are loose, always ensure you remove the cable clamp from the negative terminal first. It’s marked with a minus (-) sign and the positive terminal has a plus (+) symbol. The cables may not lift off easily and may need to be gently wiggled free until the clamp comes off the terminal. If there is a lot of corrosion present, you may need to use of pair of locking pliers. Be careful not to short any spanner or tools you use against the nearby metal objects when they’re in contact with the marine battery.
2. Secure the loose cables using tie and duct tape so that they cannot accidentally fall back onto the terminals.
3. Examine the condition of the battery cables and clamps for corrosion or excess wear. Should any damage appear extensive, immediately replace the cables and clamps to avoid potential problems.
4. Check the battery's casing for cracks and the battery terminals for signs of damage. If you find either, replace the marine battery.
5. Mix a small quantity of baking soda with water and paste directly onto the terminal posts.
6. Dip a toothbrush in water and use it to scrub the baking soda into the terminal posts and cable clamps. Skin and eye protection should be worn.
7. You can also use a battery terminal cleaner brush on it. Clean the insides of the cable clamps by using a clamp cleaner or use a plain soap-free steel wool pad.
8. Wipe the terminals, battery cover and cable clamps dry with a clean, disposable, lint-free rag.
9. Use a product like CRC Battery Terminal Protector or Lanox. This comes in an aerosol spray pack and provides a protective film over the terminals to reduce the liklihood of corrosion build-up. Cover all exposed metal surfaces on the battery posts, battery cables, and clamps.
10. Replace the positive clamp first and then replace the negative clamp. Tighten them securely with the spanner and replace the battery box cover.

Checking the electrolyte levels in a marine battery.

Remove the vent cap/s. The fluid levels should just cover the interior lead plates and distilled water (available at all supermarkets) should be added if fluid levels are down. You should habitually check the marine battery's electrolyte levels whenever you are checking your engine oil and lubricant levels in the boat. There is a fill well visible underneath the vent cap. Fill the well to cover the lead plates, but avoid overfilling the battery. Always use distilled water for servicing a marine battery. Ensure the vent caps is replaced and tightened after checking the fluid level. Never add acid to a marine battery.