Battery voltage

pinto12

Hi
The car wouldn't start anymore with the 3.5 year old battery on my weekend vehicle (I noticed engine turn over was getting weaker over time). Naturally I though time to replace. Checking voltage with a multimeter I was surprised to read 12.3V. Charged at home to 12.85 & left disconnected. A day after it's 12.55 and a day after 12.52.
I'm not knowledgeable re car batteries but does this make sense?
Thanks

thecardoc3

Yes. Having a "surface charge" immediately after charging is normal, and over a few hours that will discharge itself and the actual charge level will then be seen. This however does not show you the true health of the battery. What's important is what is the battery voltage during and shortly after a current load has been pulled from the battery. For example, what is the battery voltage while the engine is being cranked by the starter? This check should be made after cranking the engine for fifteen seconds.