Golf cart batteries are six volt deep cycle lead acid batteries widely used to power small systems. The deep cycle design provides more energy storage than starting batteries like those used in automobiles. This allows golf cart batteries to go further between recharges. The most accurate method to test golf cart batteries is to use a hydrometer to check the specific gravity of the fluid in each cell of the battery. The results tell you if the battery is charging properly.
Disconnect the battery from the golf cart or other system and place it on a battery charger. Follow the battery charger manufacturer’s directions to bring the battery to a full charge.
Allow the battery to sit for about 12 hours after you remove it from the charger. This allows any surface charge that would give you an inaccurate reading to dissipate. Do not reconnect the battery to the golf cart until you have finished testing the battery.
Remove the cell caps. These are the plastic caps on top of the battery. Insert the hydrometer probe into the first cell. If you have a squeeze bulb hydrometer, squeeze the bulb and release it to draw fluid into the hydrometer. For syringe hydrometers, pull up on the plunger to draw up fluid into the hydrometer.
Read the specific gravity from the hydrometer indicator. Return the fluid to the cell. You must repeat Step 3 for each cell in the battery. Ideally, the specific gravity should be about 1.265, which indicates a 100 percent charge. A reading of 1.12 or less indicates the battery is fully discharged and will not accept a charge. If a cell varies by 0.05 or more from other cells, it may be a dead cell.
Like all lead acid batteries, golf cart batteries contain sulfuric acid, which is toxic and can cause severe chemical burns. Always wear safety goggles and protective gloves when working with golf cart and other lead acid batteries.