The most accurate test of a deep cycle battery will require an inspection of the battery's fluid condition and voltage after charging service is completed. It’s easy to do this, and you’ll only need a few inexpensive, multipurpose tools - a hydrometer and DC voltage meter (You can find them at your local auto parts or battery retail store.)
If your battery is giving you trouble, you can follow these troubleshooting steps on your own.
Before you take steps to troubleshoot a battery, be familiar with the potential risks connected with handling any battery. This includes wearing personal protection equipment (goggles, gloves, etc); removing metallic objects such as jewelry; and working in an open, well ventilated area.
Before your inspection, always make sure you fully charge the battery to get an accurate reading of the battery condition. Or, if you can’t charge the battery, let it sit for one hour after use.
Check for Damage
You can often detect problems with your battery simply by looking for:
- Broken or loose terminals: If any terminals or connections are loose, damaged, or corroded then they can result in dangerous short circuits.
- Leaking or a damaged battery case: In flooded batteries, a leak can indicate a damaged battery case. While the damage wouldn’t prevent the battery from working, it is dangerous to operate a battery with a damaged case. (Leakage will not occur with an AGM battery, even with a damaged case.)
- Dirt and grime: During your inspection, check the top of the battery and terminals for dirt and grime. This corrosive buildup could cause the battery to self-discharge when not in use. Make it a point to remove any corrosion from your battery terminals or connecting cables to ensure the battery is working and charging efficiently.
Simple and Safe Inspection Process
- Using a hydrometer, to measure the specific gravity of the acid within the battery fluid.
- Following battery charging service, the hydrometer reading of all cells should be at least 1.225 -- and show less than 50 points difference between the high and low reading.
- A fully charged and healthy battery will show clear fluid with no discoloration and a hydrometer reading of 1.265.
- Battery voltage after charge is an effective indication of battery health.
- Batteries with less than 100% voltage should be recharged before use. A 12-volt battery will read 12.6 volts or higher after charge; a 6-volt battery will read 6.4 volts or higher after charge.
- Make sure the battery terminals are free of corrosion before testing.
Load Test Inspection
- Batteries must be at 100% voltage before a load test can be applied.
- When load testing remove all battery cables from their terminals.
- Using a load tester, apply a 15-second load equivalent to 50% of the battery's CCA rating.
- Refer to the load testers minimum passing voltage to determine the battery condition. If the test voltage is below the minimum, replace the battery.
Check now -- save big later. Just like with a car, don’t let small problems with your battery go unnoticed; small problems now can lead to much bigger problems (and more expensive) problems later... and end up damaging your battery beyond repair.
Get the most life out of your deep cycle battery by checking for small things and performing tests regularly.