AGM battery - typical readings

[G80indy]

I'm curious what everybody's typical battery voltage is? After a drive it's 12.68, with the parasitic draw and efficient dynamics protocol. The car likes to draw from it more than charge it. After the car is off for a while it winds down the parasitic draw and it goes up to 12.9-ish.

I take random readings with voltmeter— and have to occasionally top it off with the CTEK. I try to get it to around 12.85-12.90v after the surface voltage fades...

Looking for what you all typically see between drives and battery tender supplements.
It is hard to gauge health of an AGM sometimes...

[G80indy]

Bueller ?

....... Bueller ?


??

[pjk380]

I see around 12.5-12.6 on my 4 year old AGM battery. When is falls below that and after sitting for a week or so I'll throw on my CTEK charger. Once the battery is topped off, it will sit at 12.7-12.8 for a couple days then drop down to 12.6.

[DrFerry]

Voltage of a failing AGM battery I had was 12.7V. After replacing with a Duracell Platinum AGM the voltage was 13.4V. That was about two years ago. See photos below.
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[TX]

12.9 is a 100% acceptable charge on a resting agm battery. Now hold up let me go meter mine. I am at 12.52 after a 3 hour rest in the garage after work. Battery is probably a year and a half old...Bosch 850bagm. Alternator is a year older than that so I have no issues in either aspect and you should have no concern at all if you’re resting at 12.9v on an a solid agm. I typically don’t consider it to be an issue unless you have 12.2 or less on a resting battery and even that will still start your car in a pinch.
Edit: I’ll update this with some more info regarding my earlier post... For an AGM 12.8 is considered 100% resting voltage charge. 12.2 is 25%.

[Helmsman]

And these voltage level are after unlocking the car, or have you snake out the meter lines so you don't need to? Even when my battery was new it went down to 12.5v or so soon as I opened the car.

My battery isnt new anylonger, in fact have some issues, hence interested in some fresh data.

[G80indy]

Originally Posted by Helmsman

And these voltage level are after unlocking the car, or have you snake out the meter lines so you don't need to? Even when my battery was new it went down to 12.5v or so soon as I opened the car.

My battery isnt new anylonger, in fact have some issues, hence interested in some fresh data.

Yea my point being these cars put a drain on the batteries and don't aggressively charge when driving either due to efficient dynamics... I think a CTEK or similar is really important to extend decent battery life...

[Helmsman]

Originally Posted by 330indy

Yea my point being these cars put a drain on the batteries and don't aggressively charge when driving either due to efficient dynamics... I think a CTEK or similar is really important to extend decent battery life...

Never understood what the "efficient dynamics" meant other than disengaging the alternator during WOT. Reading the charge current it is certainly on all time. Or at least alterntor output current that is, which doesn't have to be the same I guess.

Edit: measured charge voltage directly on the battery, same as on the scanner so no fuzzy regulator device in between. Also hooked up a Ctek (7A) which produced slightly higher voltage than the generator so yeah, the alternator can spit out high current but decided my battery doesn't need more. Like you said, low charge vs drain and in addition a Covid battery after too little driving in my case.