Drain Testing

Check for current drains on the battery in excess of 50 milliamps with all the electrical accessories off and the vehicle at rest. Current drains can be tested with the following procedure.

WARNING: DO NOT ATTEMPT THIS TEST ON A LEAD-ACID BATTERY THAT HAS RECENTLY BEEN RECHARGED.

CAUTION: Do not crank the engine or operate accessories that draw more than 10A. You could open the fuse in the meter.

NOTE: Many computers draw 10 mA or more continuously.

With Multimeter Test Procedure

NOTE: Use an in-line ammeter between the battery positive or negative post and its respective cable.

1. Insert the test leads in the input terminals shown.
2. Turn switch to mA/A dc.
3. Disconnect battery terminal and touch probes.
4. Isolate circuit causing current drain by pulling out one fuse after another while reading the display.
5. Current reading will drop when the fuse on the bad circuit is pulled.
6. Reinstall fuse and test components (including connectors) of that circuit to find defective component(s).







The current reading (current drain) should be less than 0.05 amp. If it exceeds 0.05 amp, it indicates a constant current drain which could cause a discharged battery. Possible sources of current drain are vehicle lamps (such as underhood, glove compartment, luggage compartment) that do not shut off properly.

Electronic Drains Which Shut Off When the Battery Cable Is Disconnected
1. Repeat Steps 1 through 6 of the voltmeter drain testing.
2. Without starting engine, turn ignition ON for a moment and then OFF. If applicable, wait one minute for the illuminated entry lamps to turn off.
3. Connect the voltmeter and read the voltage.

The current reading (current drain) should be less than 0.05 amp. If it exceeds 0.05 amp after a few minutes, and if this drain did not show in previous tests, the drain is most likely caused by a malfunctioning electronic component. As in previous tests, remove the fuses in fuse junction panel one at a time to locate the problem circuit.

ALTERNATE TEST METHOD
Use Rotunda Power Sensor Plus Electronic Battery Test 162-00002 or equivalent. Follow the manufacturer's defined test procedure.