What is a good 12V battery voltage reading?

[Kern Dog]

https://www.batterystuff.com/kb/fre...ies-faq/12-volt-battery-reading-13-volts.html

From that article:

"All Lead acid batteries (Gel, AGM, Flooded, Drycell, etc) are made up of a series of 2.2 volt cells that are bridged together in series to reach their final desired voltage. For instance, a 6 volt battery will have 3 cells (3 x2.2= 6.6 volts), a 12v battery for a motorcycle for a motorcycle will have 6 cells (6 x2.2=13.2 volts) and so on. That 2.2 volts is the fully charged, straight off the charger number. The actual resting voltage, or the voltage a battery will settle at 12-24 hours after being removed from the charger, is closer to 2.1 volts per cell, or about 6.4 volts for a 6v battery, and 12.7 volts for a 12v battery. These numbers assume 100% healthy cells, and may vary a bit lower for older batteries."

Thank you!

 

[1967coronet]

 

[Kern Dog]

Ford telling me that my 2 year old battery in my F150 is good today.. even though within 2 days of charging my auto stop/start won't work because the truck knows it's charging the battery. Tech put it in their fangled tester and it showed 12.23 volts and drew only 379 CCA on it's 760 CCA rating. Charged it and then it tested fine.. even though I've done this twice myself they wouldn't give me a new battery. I booked an appointment for next Friday so they could do it again... lol I have prepaid maintenance and these f'rs are going to learn a lesson or three.

This is not encouraging. New tech is SO great that a 2 year old battery is already worn out?

 

[dadsbee]

Probably just a bad battery, or a parasitic draw in the truck. If they don't give me a new battery we'll never know. I generally get about 8 years out of AGM's that I put in aircraft.

 

[Pops1967GTX]

13.8 - 14.2 volts.
If under you are not charging the battery properly. if over , you are overcharging.
​

 

[Kern Dog]

The voltmeter in my '70 Charger is to the right of 13 volts after the car warms up. Same with the one in 2 other cars. I thought that the charging system is supposed to run at just under 14 volts. I assumed that it was this high to allow for voltage drop through the system and that the battery should test in the mid 12s.
Then again, I have almost no experience with later model computer controlled cars. I only understand that they would need a higher and more stable supply due to the multiple sensors and computers.
The chart below had me curious:

To think that a battery testing at 12.06 Volts is technically half charged? That seems strange to me. Just using basic math, I naturally assumed that at 6 volts that the battery would be at half of a charge.

 

[Kern Dog]

View attachment 862800
No agm application for the 69.

Not sure what you meant.
Are you stating that you don't have one or that nobody makes one?
My new one is smaller than a regular lead/acid battery and fits in my battery box just fine. My battery is in the trunk in a steel box from an A-100 van. The stock battery tray is sized okay for this battery if you wanted one.
2009 Challenger on a 10 year old battery? Wow!

 

[69L48Z27]

For me, a normally charged battery sits around 12.5v. When the car is running I’ll look for around 14 but not much if any more.

Schumacher makes chargers to handle the AGMs, even in a maintainer. An AGM needs a desulfate cycle.

 

[Kern Dog]

This is the AGM that I just bought. It is about the same size as the Optima but weighs less. Both this and the Optima were smaller than my regular battery.

 

[Dennis H]

Not sure what you meant.
Are you stating that you don't have one or that nobody makes one?
My new one is smaller than a regular lead/acid battery and fits in my battery box just fine. My battery is in the trunk in a steel box from an A-100 van. The stock battery tray is sized okay for this battery if you wanted one.
2009 Challenger on a 10 year old battery? Wow!

No AGM would fit in the Coronet. Too tall OR too long. Challenger is 10 year old original and want to put AGM in when time comes. The tablet is reading over 14 when running down the highway.

 

[Dennis H]

 

[dadsbee]

How you make an AGM fit Dennis..

 

[Dennis H]

What’s the foam at top of radiator? Improve cooling at idle?

 

[Kern Dog]

Probably to ensure air passes through the radiator rather than around it.

 

[dadsbee]

Super Bird radiator seal..

 

[Dennis H]

EXCUSE ME. Bird is the word. All in for forcing/channeling air. Just learned of missing seal at rear of hood on mine.

 

[dadsbee]

This one..

 

[Dennis H]

Only Birds got em?

 

[dadsbee]

Only Birds got em?

Foam to seal the radiator, top and bottom tanks. Bird only as far as I know conisidering the restricted air inlet dimensions on the nose (I run with my bottom pan removed). Possible Daytona's got them too..

 

[Dennis H]

See that OP? Starts with batteries and goes to the Birds quick...