QI have just purchased a CTEK battery analyser to check my leisure batteries as we’ve developed battery problems. All of my batteries are 110 Ah (Amp hours) and 680 CCA (Cold Cranking Amperage). I fully charged all three before carrying out the test. The analyser told me one required replacing because it was showing 575 CCA. How low can the CCA go before it’s classed as useless? It would be good to know because, by using the analyser, I would be able to change a battery before it starts giving problems. A CLARKE
ATONY REPLIES… The good news is that it appears not to be a high rate discharge tester, the bad news is that Cold Cranking Amperage (CCA) is related to engine starting, not long discharges at a low rate that boat’s domestic batteries are subject to unless a large inverter is being used. Add to that the fact that such testers’ algorithms differ from maker to maker and tend to give different results. One authority even says that a starting battery with a low CCA can give several more months or years more use, probably more so with the long slow discharges boat batteries get.
I have no idea how low the CCA can go before the battery is considered to need replacing because, for a domestic battery use, it’s a pretty meaningless figure. When the Ah capacity falls to 50% of the original or when a cell starts to fail, the battery needs replacing.
Unless you fully charge the batteries at least once a week (and I do not mean when an amp hour counting meter says they are at 100%) then most boaters will sulphate their batteries so they slowly lose capacity. You can sulphate a battery within weeks but most take far longer than that.
Even if you do charge your battery to 100% at least once a week, standard ‘leisure’ type batteries have a very limited cyclic life (typically between 150 and 300 cycles) and once that is used up are likely to develop short circuits within a cell or cells.
I note the analyser stresses that you need to fully charge any ‘low’ batteries before re-testing them but makes no mention of letting them stand overnight to dissipate the surface charge and allow time for any shorting cell to discharge. I think this omission could lead to false ‘okay’ readings. Check with CTEK who know the algorithm their tester uses.