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

[maxwedge]

Welcome to AF. Any temp changes after charging ? Give it a couple of days, see where it goes to. Possible this battery just won't hold a charge.

[shorod]

It's possible for the voltage to read acceptable when using a multimeter since they, by design, do not load the circuit they are measuring. So the "old" battery might have voltage, but not capacity. You should try monitoring what the voltage drops down to when trying to start the car.

Modern cars require pretty robust batteries, and for the past 10 or so years, if you're able to get more than 3 years out of battery, at least here in the Midwest, you're doing well. Locations where the temperature is a bit milder and more consistent batteries might last longer.

-Rod

[grouseman]

I would suggest you load test the battery. A battery voltage may look good but under the load of starting the cold cranking amps are too low. You can buy a battery tester at Harbor Freight for $18 that will put a load on the battery similar to starting the engine. My thought anyway. Grouseman

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100 Amp, 6/12V Battery Load Tester

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