OEM 12V AGM battery replacement; how long post manufacture is still good?

Are we talking about the hybrid battery or 12v?

 

i had the same thing when i replaced mine last summer. i think it's fine. yo might want to put a charge on it, as the car does a poor job.

 

best thing to do is bring a 12 volt DC voltmeter and test the battery right there at the counter. if its dead I dont want it. Its been sitting on the shelf dead for a year. Sulphation.

The OEM's a re the best battery's but they need to be healthy. Lots of us put that new battery on a charger and make sure its full before installing it. Then once its installed you can do a minor load test on it. But that requires a voltmeter also..

 

Maybe have the dealership connect it to an electronic load tester, show you the outcome. IIRC the OEM is 325 CCA. If it's in good shape it should read well above that, say 375~390.

My 2cents: It's good for both the seller and buyer to do this test as a matter of course, with every battery sale.

I suspect it'll be ok, a battery carefully stored, without the relentless back ground loads it would have if installed in a modern car, can weather some shelf time.

I'd second starting it off with a charging session. A smart charger, around 3 amp range would be good. Verify max amperage in Owner's Manual.

 

It should be ok.

Do you have a voltmeter? Measure the open circuit voltage and tell us what you get.

 

If just reading voltage: start with a full charging session, with a smart charger, let it run to completion. Then drive the car a day or two. If possible pop the hood in the evening (to avoid any subsequent wake-up of the car's systems). First thing the next morning check the voltage at the jump point. A new AGM in good condition should read at least 12.7something volts.

Voltage alone might be deceptive though, especially if the battery isn't initially recharged. A battery sitting on a shelf can be very viable, but it's voltage dropped a bit. The electronic load testers test voltage and the CCA. With a battery that's in good condition, just voltage lagging a bit (due to protracted storage), it may come back with stellar CCA, lowish voltage, and a verdict "good but charge".

The dealership has these testers, just sold him the battery, should be willing to demonstrate it's viability.

You can DIY such a test with Solar BA9, for example.

 

11 years is an exceptional run. the quality probably isn't that good anymore. figure an average of 6-7 years in your climate, all else being equal.