Bookmark this page
Save WBCCI Show your support for WBCCI. Vote NO on the name change. CLICK HERE to get your avatar.
Home | Pictures | History | Links | Projects | Video | Voyages | Miscellaneous | Contact | Latest Updates | Site Map | Search

Battery Load Testing

Load testing is one way of testing a battery. A load test is simply putting some amount of load on the battery and seeing how it responds. A load tester can be purchased at most auto parts stores or places like Harbor Freight Tools. They vary in capacity from 65 amps load to 500+ amps. They usually have 1 or 2 gauges. A volt gage and an amp gage. Some of the cheaper models only have a volt/condition gage. A load test should only be performed if the battery is near or at full charge. Also, many auto parts stores and battery centers can load test a battery.

The process is simple:
  • Connect the load tester to the battery, plus lead (red) to plus and minus lead (black) to minus.
  • Note the voltage of the battery on the gage.
  • Apply the load for 15 seconds.
  • monitor the battery volts during the loading process
  • Remove the load
  • Note the battery volts after the load has been removed

Load tester connected

This is the load tester connected to the battery. The gauge on the left is the current reading (load) and the gauge on the right is the battery volts/condition. This test is performed before any real maintenance is done. Afterall, if it doesn't test good here, it will be replaced. The knob on the tester is what applies the load - anywhere from zero to 500+ amps.
With the tester connected and no load on the battery the voltage shows about 13.4 volts. This battery is fully charged and ready to be tested.
The know is turned up to the max for a heavy load test. The current draw starts out at just above 500 amps and quickly drops to 400 amps and holds. After 15 seconds the load tester beeps indicating the test is complete and the dial is turned counterclockwise to remove the load.
The load is removed and the battery settles out at about 12.8 volts.

The results

The test is complete,the battery passes and we can continue with maintenance.
This test indicated that the plates in the battery have not built up a bad sulfate layer and can not only deliver a load but will take a charge properly. A battery which is in poor condition would not deliver as much current and would would drop in volts to an unacceptable level (indicating higher internal resistance). A battery that does not pass this test has coated plates and will not take a proper charge.

Now on to Battery Maintenance.

All Contents and images Copyright 2012 ArchNevada Design unless otherwise noted. All rights reserved.