Battery, Checking

A weak battery can be caused by:
- Generator (GEN) drive belt slipping (replace belt if glazed).
- Ground (GND) straps corroded, loose or broken.
- Generator or voltage regulator malfunctioning.
- Generator warning light -K2-bulb failed.
- Poor Ground (GND) connection between generator warning light -K2- socket and circuit board.

Battery and cable terminals should be cleaned and coated with acid-resistant grease to prevent corrosion.

Visual checks
- Check for cracked or leaking battery case.
- Check for loose or corroded terminals.
- Check electrolyte level (below MIN mark). If electrolyte is low, refill with distilled water and charge battery for several minutes after cells begin gassing (boiling).


CAUTION!
- DO NOT overfill. Overfilled batteries can boil over.
- Too little electrolyte reduces the service life of the battery.


Hydrometer test (specific gravity)
(Batteries with removable caps)


NOTE: Calibration of the hydrometer must be checked frequently to ensure accuracy.


CAUTION!
DO NOT expose a fully discharged battery to freezing temperatures; the battery will be damaged.


- Test electrolyte in all cells.

Average specific gravity should be at least 1.225

Specific gravity % charge
1.265 100%
1.225 75%
1.190 50%
1.155 25%
1.120 0%

- Correct for electrolyte temperature if necessary:
- For each 10° above 80 °F (26 °C), add 0.004 to hydrometer reading
- For each 10° below 80 °F (26 °C), subtract 0.004 from hydrometer reading

If specific gravity is above 1.225:
- Load test battery.

If specific gravity is below 1.225:
- Charge battery.

If specific gravity varies by more than 0.050 between cells:
- Replace battery.