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Testing the health of the 12v AGM battery

19K views 25 replies 15 participants last post by  jtb122536  
Long time Volt owner and aircraft mechanic.

The 12V AGM battery's that lives comfortably inside our Volts cabin should easily last 9-10 years, maybe longer. Understand this battery is never being taxed in anyway and its being maintained by computer controlled circuity. Compare this to a regular car battery that lives in the engine compartment, deep cycled daily, and charge controlled by the simplest of circuits prone to failure. NO Comparison!

The only way to properly test a battery is with a load tester, not the electronic types they have at auto parts store, but a real one with a load bank. These are serious looking heavy machines not something you hand carry out to a car. I have drive-up access to a real load tester and I tested annually ... pretty much a waste of time. Out of curiosity I had various parts stores & battery shops check my AGM, guess what "they all said" it's going band and I should purchase a new AGM battery. Tools!

Can a 2V cell go bad inside our 12V AGM battery's, yea but it's rare, and if that happens you can read the crazy story's here. For piece of mind all you really need is a simple Volt meter. In the morning test your battery, if it read 12.1 to 12.3 Volts it's probably good ... if the voltage drops to 12.0 time to start thinking about a new battery.

BTW - the chap I sold my 2011 Volt to is still using the original battery, that's 9 years now. He said the battery measures somewhere south of 12.1 now but he's on a mission to see how long he can milk it out. Whatever floats your boat!