Battery Diagnosis Worksheet

1.    Visual Inspection and Electrolyte Level:  Check battery for corroded terminals (warning—it’s what’s on the inside that counts), loose or broken clamps, cracks, leaks, low electrolyte level, missing vent caps, missing or bad battery hold downs, correct size and capacity for vehicle, built-in hydrometer and acid powder on top.

Terminals need cleaning ___  Terminals have been cleaned ___
Electrolyte level is OK ___  Electrolyte level is too low ___ Other problems __________________________________

2.   Determine State of Charge: Is battery up to 70% so it can be tested?

Using hydrometer: measure specific gravity of all six cells and record here: ____  ____  ____  ____  ____  ____ 
Are all above 1.240? Yes ___  No ___
Is there a difference of 0.050 or more between cells? Yes ___  No ___ (if yes, replace battery)

Using digital voltmeter: Remove surface charge by 1) turning on headlights for 3 minutes ____ or load testing battery 100-200 amps for 15 seconds ____. When battery voltage comes back up, where does it come to? 12.6v (100%) ___  12.4v (75%) ___   12.2v  (50%) ___  12.0v (25%)  11.8v or lower (0%) ___      
Battery is ready to load test ___   Battery needs charging ___

3.   Load Test Battery: (Capacity Test) This tests if the battery can put out enough volts and amps, that it is not sulfated. Hook up tester so you measure the amps going through the carbon pile and volts.

CCA rating ______, divided by two = ______.
Load test at this amperage, (but not too much more than 200 amps) for 15 seconds, and record the voltage at 15 seconds here: ______
Voltage is above 9.6v—passes ___  below 9.6v—fails ___

4.   Check Parasitic Draw when battery turned off.  Connect amp meter in series, should be no more than 0.050 amps or 50 ma after the computers have shut down.
How much? ____  OK ___ Not OK ___

5.   Use Capacitance Tester. Follow instructions on screen
Pass: ____  Fail: ____  Readings: ______________________________