Specific Gravity Test

DO NOT ADD WATER BEFOR TESTING (Flooded batteries only)

   1. Fill and drain the hydrometer 2 to 4 times before pulling out a sample.
   2. There should be enough sample electrolyte in the hydrometer to completely support the float.
   3. Take a reading, record it, and return the electrolyte back to the cell.
   4. To check another cell, repeat the 3 steps above.
   5. Check all cells in the battery.
   6. Replace the vent caps and wipe off any electrolyte that might have been spilled.
   7. Correct the readings to 80o F: Add .004 to readings for every 10o above 80o F, ( 6o above 26o C)
Subtract .004 for every 10o below 80o F, ( 6o below 26o C)
   8. Compare the readings.
   9. Check the state of charge using “Open Circuit Voltage” table below.

The readings should be at or above the factory specification or 1.280 ± .005. If any specific gravity readings register low, then follow the steps below.

   1. Check and record voltage level(s).
   2. Put battery(s) on a complete charge.
   3. Take specific gravity readings again.

If any specific gravity readings still register low then follow the steps below.

   1. Check voltage level(s).
   2. Perform equalization charge. Refer to the Equalizing section for the proper procedure.
   3. Take specific gravity readings again.

If any specific gravity reading still registers lower than the factory specification or 1.280 +/- .005 then one or more of the following conditions may exist:

   1. The battery is old and approaching the end of its life.
   2. The battery was left in a state of discharge too long.
   3. Electrolyte was lost due to spillage or overflow.
   4. A weak or bad cell is developing.
   5. Battery was watered excessively previous to testing

Batteries in conditions 1 — 4 should be taken to a specialist for further evaluation or retired from service.