[Michael Hill]

Originally Posted by Al Skierkiewicz

Guys,
There are a few things about batteries you need to know. A battery might show something above 12 volts (no load) when it comes off the charger due to a condition known as 'surface charge'. This voltage will drain back down to the 12 volts as soon as you start to draw current from the battery. That is why no load battery testing is inconclusive when checking the state of charge or the condition of the battery. Charging SLA/AGM cells requires that a voltage higher than the cell voltage be forced on the battery. The higher the voltage, the more charge current is pushed into the battery to reverse the chemical reaction that takes place inside. The manufacturers state that currents in excess of six amps will damage the battery. However, the smart chargers provided in the KOP and equivalents will back down from the six amp maximum as needed during the charge cycle. So setting the charger at 6 amps does not mean it will provide six amps during the entire charge cycle. Any additional current in excess of what can be used to reverse the chemical reaction will generate heat. In our batteries this excess heat can cause boiling of the electrolyte within the cell, deformation of cell plates, leaking of the battery and explosion in rare cases. That is why inspectors will ask you to remove battery chargers that are in excess of six amps and are not smart chargers. We regularly will find teams trying to use 50 amp car chargers in the pits. These are extremely dangerous for use in the pit and will guarantee early battery failure with no warning. While the KOP charger does allow current selection below 6 amps (i.e.4 and 2 amps) selecting these lower settings will not measurably extend the life of the battery but if you have the time to wait, the lower current may be a more efficient charge method.
The best method of checking battery state of charge is under a controlled load. The Battery Beak is an excellent simple charge tester that you can carry in your pocket. For really accurate checks that mimic the manufacturer's specification, use a West Mountain Radio CBAIII.

I was seriously hoping Big Al would come in this thread.