Battery Testing

BATTERY INSPECTION Batteries should be carefully inspected on a regular basis in order to detect and correct potential problems before they can do harm Examine the outside appearance of the battery. Look for cracks in the container. The top of the battery, posts, and connections should be clean, free of dirt, fluids, and corrosion. If batteries are dirty, refer to the Cleaning section for the proper cleaning procedure. Repair or replace any damaged batteries. Any fluids on or around the battery may be an indication that electrolyte is spilling, leaching, or leaking out. Leaking batteries must be repaired or replaced. Check all battery cables and their connections. Look closely for loose or damaged parts. Battery cables should be intact; broken or frayed cables can be extremely hazardous. Replace any cable that looks suspicious.

Add water, never acid, to cells (distilled water recommended). For Fully Charged deep cycle batteries, add water to the level of 1/8 below bottom of vent well. For Discharged batteries, only add water if the plates are exposed. Add just enough water to cover the plates, then charge the batteries. Once fully charged, add water to the proper level indicated above.

CLEANING BATTERIES Batteries seem to attract dust, dirt, and grime. Keeping them clean will help one spot trouble signs if they appear and avoid problems associated with grime. Check that all vent caps are tightly in place. Clean the battery top with a cloth or brush and a solution of baking soda and water. When cleaning, do not allow any cleaning solution, or other foreign matter to get inside the battery. Rinse with water and dry with a clean cloth. Clean battery terminals and the inside of cable clamps using a post and clamp cleaner. Clean terminals will have a bright metallic shine. Reconnect the clamps to the terminals and thinly coat them with petroleum jelly to prevent corrosion. Keep the area around batteries clean and dry.

SPECIFIC GRAVITY TEST Water Batteries Only Do not add water at this time. Fill and drain the hydrometer 2 to 4 times before pulling out a sample. There should be enough sample electrolyte in the hydrometer to completely support the float. Take a reading, record it, and return the electrolyte back to the cell. To check another cell, repeat the 3 steps above. Check all cells in the battery. Replace the vent caps and wipe off any electrolyte that might have been spilled. Correct the readings to 80o F: Add .004 to readings for every 10* above 80* F Subtract .004 for every 10* below 80* F. Compare the readings. Check the state of charge using the below table. The readings should be at or above the factory specification of 1.277 +/- .007. If any specific gravity readings register low, then follow the steps below. Check and record voltage level(s). Put battery(s) on a complete charge. Take specific gravity readings again. If any specific gravity readings still register low then follow the steps below. Check voltage level(s). Perform equalization charge. Refer to the Equalizing section for the proper procedure. Take specific gravity readings again. If any specific gravity reading still registers lower than the factory specification of 1.277+/- .007 then one or more of the following conditions may exist: The battery is old and approaching the end of its life. The battery was left in a state of discharge too long. Electrolyte was lost due to spillage or overflow. A weak or bad cell is developing. Battery was watered excessively previous to testing.

VOLTAGE TEST For accurate voltage readings, batteries must remain idle (no charging, no discharging) for at least 6 hrs. Disconnect all loads from the batteries. Measure the voltage using a DC voltmeter. Check the state of charge with the below table. Charge the battery if it registers 0% to 70% charged. If battery registers under the below table values, the following conditions may exist: The battery was left in a state of discharge too long. The battery has a bad cell State of charge as related to specific gravity and open circuit voltage

                  6V     8V      12V     36V      48V
100*1.277  6.37   8.49   12.73   38.20   50.93
90*  1.258  6.31   8.41   12.62   37.85   50.47
80*  1.238  6.25   8.33   12.50   37.49   49.99
70*  1.217  6.19   8.25   12.37   37.12   49.49
60*  1.195  6.12   8.16   12.24   36.72   48.96
50*  1.172  6.05   8.07   12.10   36.31   48.41
40*  1.148  5.98   7.97   11.96   35.87   47.83
30*  1.124  5.91   7.88   11.81   35.44   47.26
20*  1.098  5.83   7.77   11.66   34.97   46.63
10*  1.073  5.75   7.67   11.51   34.52   46.03