I read with interest your Tech Talk article on “Are My Batteries Good For Another Season”. I am not an electrician or a mechanic but I noted that you did not mention Amps as a measure of whether or not a battery is still ‘good’. I had my 8D wet batteries tested and the following was reported: Battery 1 - 1052 CA, Battery 2 - 920 CA, Battery 4 - 656 CA, Battery 3 - 58 CA (starter battery). All read voltage around 13.5V except #3 which read 13.24V. Battery 3 was replaced and now reads 1324 CA and 13.61V. Can you tell me the difference between what you suggested and how my batteries were tested?
A Cranking Amps (CA) or Cold Cranking Amps (CCA) rating is for testing batteries for engine starting. A deep cycle battery needs to be tested with a capacitance tester. Better still is to do the following test:
If your batteries were perfect, they would last 20 hours and you would draw a total of 720 AHrs. In reality, you are likely to get 90% or less. With age, a battery can provide only a fraction of its original spec.
As a warning, performing this test does put your batteries under some strain. Therefore, you should only perform this test a few times within a battery’s lifetime.