A new battery does not develop its full performance capabilities until it has been through several discharge/charge cycles. This means a new battery may not be capable of producing its optimum current and cold cranking amps (CCA).
If a new battery that has not gone through a cycling period is tested using a conductance-type battery tester, the resulting CCA may be lower than indicated on the battery's rating label. This could lead to condemning an otherwise good battery.
Conductance is a measurement of a battery's current producing capability. Conductance testers (Fig. 5) can accurately identify batteries that have reduced performance after being in service, but should never be used to determine the state of health, state of charge or CCA rating of a new, never installed battery. Also, conductance testing of new batteries should never be used to determine the warrantable condition.
Fig. 5
To check the condition of a battery prior to installation to be sure there is adequate voltage to start the vehicle, measure open circuit voltage (OCV) using a digital voltmeter (DVOM). An OCV of 12.24V is adequate to provide the power requirements for starting most vehicles under most conditions. The battery should be in service for several days before performing a conductance test.
Battery Testing Procedures
Follow these tips when using a conductance tester to ensure accurate test results. Using non-approved adapters or improper test procedures can lead to failing test results for batteries that are not defective.
Be sure the battery in the tester is good or you may get inaccurate results. To check the conductance tester, be sure OCV on the tester matches the OCV measured with a known-good DVOM (may vary slightly due to different internal resistance).
Be sure to get good connections between the battery terminals and the tester clamps. Each tester clamp has two jaws. Each jaw is wired to a different part of the tester, and it is essential that both jaws make good contact.
If the connections to the battery terminals in the vehicle are in doubt or the tester displays REPLACE BATTERY or BAD CELL - REPLACE, disconnect the battery being tested from the vehicle. Retest the battery with both of the vehicle's battery cables disconnected from the battery.
When using an adapter, be sure the adapter makes good contact with the lead terminal surface on the battery.
Never use steel bolts, nuts, washers, etc., when testing a side terminal battery. Only use the adaptors included with the conductance tester. The coating on other adapters may affect the tester's accuracy.
Battery Warranty
ACDelco batteries are covered by a comprehensive warranty program. Any independent service center can accept an ACDelco battery that is under warranty and not functioning properly from a customer for return, even if the battery was purchased from another retailer or service center. ACDelco will warrant the battery, and in the process, the service center may earn some additional service business and customer loyalty.
- Thanks to Mike DeSander and Brad Busboom
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