Clever battery testing device?

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peterandjeanette

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I need to check several batteries in our boat.

The main engine starting battery ( 12V 110 ah ) seems fine.

The domestic batteries ( 4 x 12V 110 ah - same as engine starter battery ) seem to deplete fairly quickly. Each battery needs testing. They are all sealed so I can't use a hydrometer. ( I did discover that one battery was heavily corroded round the positive terminal to the extent that the clamping bolt was almost gone. No problems with the others )

I've looked at the Clarke CVT1 battery tester. Has anyone ever used one of these and if so what are your thoughts? Can it be used on sealed batteries?

All replies gratefully accepted.
 
A capacity test requires no equipment and is a more accurate measure of the performance of a storage battery. It is a bit hard on the batteries, but worth doing if you suspect a problem.
Google the procedure, but you charge the battery fully put a set load on the battery say 5A and see how long it takes to get to a very low voltage ( say 10.5 v)
Current multiplied by time gives you the amp hour capacity. Watch he voltage carefully near the end, it will drop quickly. Charge the battery again immediately. Measure each battery separately.

Your battery in theory should be 110AHrs, but when new would probably test 95-100. If its less than 70Ahrs it has not got much usable life left.
 
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A tester like the one you mention will give you an idea of a battery's engine starting capability but it is not a good guide to its capacity for domestic loads. Only a discharge test will do that, as suggested by Noelex.
 
My view is it's good to use repeatable tests that are close to the real demands on the battery.
So a quick high current test will evaluate a starter battery, a capacity test will evaluate a house battery.
Another test you can do is long term self-discharge, which tells you a little about the general health and life expectancy.
 
My view is it's good to use repeatable tests that are close to the real demands on the battery.
So a quick high current test will evaluate a starter battery, a capacity test will evaluate a house battery.
Another test you can do is long term self-discharge, which tells you a little about the general health and life expectancy.
 
peterandjeanette said:
I need to check several batteries in our boat.

The main engine starting battery ( 12V 110 ah ) seems fine.

The domestic batteries ( 4 x 12V 110 ah - same as engine starter battery ) seem to deplete fairly quickly. Each battery needs testing. They are all sealed so I can't use a hydrometer. ( I did discover that one battery was heavily corroded round the positive terminal to the extent that the clamping bolt was almost gone. No problems with the others )

I've looked at the Clarke CVT1 battery tester. Has anyone ever used one of these and if so what are your thoughts? Can it be used on sealed batteries?

All replies gratefully accepted.
Click to expand...

How old are the batteries, and how are they charged?
ie is there solar, wind or shore power charging or just engine?
Do you have a digital alternator regulator fitted?

Testing them is all very well, but this will really just confirm what you already have found - that they probably need replacing.

If they are several years old, have never been fully re charged, have been left for long periods partly discharged, then their capacity will have dropped substantially, which seems to be the case.
But this may be compounded by inadequate recharging.
 
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