Possible Bad Battery

|Hi everyone! I work for a Mazda dealership and we have a battery |tester for checking Cold Cranking Amps. Well sometimes when I do this |the tester comes back and says "Surface Charge Detected". Then it |asks me to turn on the headlights, and then turn them off. Then the |tester always comes back with some error message that I don't |understand. What is "Surface Charge Detected"? And is there anything |that I can do about it? Thank you very much.

Surface charge is additional voltage above the rated volts. Putting a small load on it for a brief period bleeds this off to the actual working voltage. As for the physics behind it, I'll have to pass.

If you're checking cold cranking amps, the first crank should dissipate it. Rex in Fort Worth

Approximately 8/22/03 13:05, Robert E. Tierney uttered for posterity:

If you use nothing but a volt meter to check the battery, it doesn't really put enough load on the battery to tell the difference between a fully charged battery and one that hasn't been fully charged. Putting a small load on the battery will result in a drop in the voltage if this is the case. This is a "surface charge"

This is rather likely on a battery that has been connected to a charger [or alternator] for a very short time on a battery that was rather discharged to begin with. Just a few minutes of charge may result in 12.6 volts or higher, but since only a tiny amount of the chemical process in the battery has been reversed, the battery would have much lower cranking capability compared to one which had been on the charger overnight.

Surface charge can also mean the battery has one or more dead or about to die cells.