Battery Load Test

A fully charged battery must have cranking capacity, to provide the starter motor and ignition system enough power to start the engine over a broad range of ambient temperatures. A battery load test will verify the actual cranking capability of the battery.

WARNING: IF BATTERY SHOWS SIGNS OF FREEZING, LEAKING, LOOSE POSTS, OR EXCESSIVELY LOW ELECTROLYTE LEVEL, DO NOT TEST. ACID BURNS OR AN EXPLOSIVE CONDITION MAY RESULT.

1. Remove both battery cables, negative cable first. The battery top, cables and posts should be clean. If green dot is not visible in indicator, charge the battery.

Volt - Ammeter Load Tester Connections:

Remove Surface Charge From Battery:

2. Connect a Volt/Ammeter/Load tester to the battery posts. Rotate the load control knob of the Carbon pile rheostat to apply a 300 amp load. Apply this load for 15 seconds to remove the surface charge from the battery, and return the control knob to off.
3. Allow the battery to stabilize for 2 minutes, and then verify open circuit voltage.

Load 50% Cold Crank Rating:

4. Rotate the load control knob on the tester to maintain 50 % of the battery cold crank rating for 15 seconds. Record the loaded voltage reading and return the load control to off. Refer to Battery Specifications.

Load Test Temperature:

5. Voltage drop will vary according to battery temperature at the time of the load test. Battery temperature can be estimated by the temperature of exposure over the preceding several hours. If the battery has been charged or boosted a few minutes prior to the test, the battery would be slightly warmer. Refer to Load Test Voltage Chart for proper loaded voltage reading:
6. If battery passes load test, it is in good condition and further tests are not necessary. If it fails load test, it should be replaced.