I have worked for 36 year as an auto & marine electrician my take on testing lead acid batteries is
1) A battery has to be suitable for the application it is used for .
A battery that "Fails" in one instance eg cold weather starting in diesel engine may be perfectly serviceable in another less demanding situation.
I am absolutely against "High discharge" load testing.
Using these testers draws more or less the same current irrespective of battery size until voltage drops down. It will often FAIL a small light car battery , which is still perfectly serviceable and tell you a heavy diesel truck battery is OK when it isn't.
I have used Modern Digital EIS testers and to be honest am not really impressed. I had a demonstration from a tool company and the battery they told me was perfect died 2 days later.
I find on vehicle testing is best. This is how I do it
1) Ensure battery starts off at 12.5V or more
2) Turn on head lights, blower fan and heated rear screen for about 3 minutes, allow voltage to drop to just below 12V. Voltage, should drop by a maximum of 0.1V every 5 seconds after that, any more and the reserve capacity is insufficient.
3) Finally , pull fuel pump fuse or in some way disable starting and operate starter motor for 10 seconds. Anything below 10.0 Volt is a fail. This is your CCA test.
If in doubt retest vehicle when fully cold.
Finally always observe for swollen battery cases, gassing from cells etc. they are always a sign of impending failure.
1) A battery has to be suitable for the application it is used for .
A battery that "Fails" in one instance eg cold weather starting in diesel engine may be perfectly serviceable in another less demanding situation.
I am absolutely against "High discharge" load testing.
Using these testers draws more or less the same current irrespective of battery size until voltage drops down. It will often FAIL a small light car battery , which is still perfectly serviceable and tell you a heavy diesel truck battery is OK when it isn't.
I have used Modern Digital EIS testers and to be honest am not really impressed. I had a demonstration from a tool company and the battery they told me was perfect died 2 days later.
I find on vehicle testing is best. This is how I do it
1) Ensure battery starts off at 12.5V or more
2) Turn on head lights, blower fan and heated rear screen for about 3 minutes, allow voltage to drop to just below 12V. Voltage, should drop by a maximum of 0.1V every 5 seconds after that, any more and the reserve capacity is insufficient.
3) Finally , pull fuel pump fuse or in some way disable starting and operate starter motor for 10 seconds. Anything below 10.0 Volt is a fail. This is your CCA test.
If in doubt retest vehicle when fully cold.
Finally always observe for swollen battery cases, gassing from cells etc. they are always a sign of impending failure.