Don't you just hate it when your battery dies unexpectedly in the middle of a match. We do too. So we test our batteries periodically and remove those from competition service which do not pass muster. We use two testing tools for this purpose.
- CBA III (previously a CBA II - Computerized Battery Analizer) from West Mountain Radio. The CBA performs a discharge test at fixed current (7.5 A), tracking voltage. The test terminates at a cut-off voltage (10.5 V) and the total Amp Hours (A hr) are reported. More A hr is better. FRC Batteries are rated for 17.2 A hr and this test returns values in the 13-16 range for good batteries. The test requires about 2 hours and discharges the battery. Because of the time investment involved, this test is run infrequently and is not useful for testing batteries in competition. It does, however, identify batteries with dead/shorted cells very clearly.
- Battery Beak from Cross The Road Electronics. This handy device measures battery voltage at three current levels (0, 1 & 18 A) and uses this to determine the internal resistance (Ω), a critical measure of battery health (lower is better), using this value to rate the battery as Good, Fair or Bad. The Battery Beak also provides %charged. Testing with the Battery Beak is fast and easy and does not significantly discharge the battery. It is therefore suitable for competition use. The battery beak is less clear in identifying a dead or shorted cell, as this does not raise internal resistance but instead is indicated as a battery which will not charge more than ~90% (should be >100%).
Test results will be posted here for reference.