Battery voltage question

[Ssiptang]

I got a new battery from advance auto last weekend because my 3.5 years old OEM couldn't handle the chicago winter. Its a autocraft gold from johnson control which I think its the same battery as Duralast gold from autozone.

Anyway, I bought one of those little battery monitors that goes into the cig lighter adapter. It reads 14.1-14.4 while car is running which I think its good. But when car is off it reads 12.1 - 12.2
Isn't good battery supposed to read around 12.5 - 12.7?
I waited for awhile to make sure all the electrics go off.

Would cold weather effect voltage reading? I also have gauges and nitrous system but they are wired on keyed source.

 

[JeremyH]

Everything sounds good to me. I wouldn't worry unless it was closer to 11-11.5 volts right after shutting the car off.

 

[Ssiptang]

Everything sounds good to me. I wouldn't worry unless it was closer to 11-11.5 volts right after shutting the car off.

I knew it was within the acceptable range but I thought it was too low for the brand new battery.

 

[JeremyH]

How long have you run the car since the new battery has been in? If the battery sat on the shelf for awhile it could take awhile to get fully charged and back up to peak. Nothing to worry about imho. My last battery lasted me 5 years and read under 12 volts for 3 of those years with no problem, when it got to the point that the car wouldn't start after sitting for a few days is when I replaced it.

 

[Department Of Boost]

I knew it was within the acceptable range but I thought it was too low for the brand new battery.

It is. I get suspect of any battery under 12v.

 

[RED09GT]

If it's plugged into the cigarette lighter, there is likely some voltage drop between the battery and the socket. If you can, check right on the battery posts.
My radar detector reads 12.1-12.2 v at the same time my multi meter reads 12.6-12.7 on the battery terminals.

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[Ssiptang]

How long have you run the car since the new battery has been in? If the battery sat on the shelf for awhile it could take awhile to get fully charged and back up to peak. Nothing to worry about imho. My last battery lasted me 5 years and read under 12 volts for 3 of those years with no problem, when it got to the point that the car wouldn't start after sitting for a few days is when I replaced it.

It has a stamp with the date on 1/14 so I'm guessing nearly full.

If it's plugged into the cigarette lighter, there is likely some voltage drop between the battery and the socket. If you can, check right on the battery posts.
My radar detector reads 12.1-12.2 v at the same time my multi meter reads 12.6-12.7 on the battery terminals.

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Ok. I didn't think about that. I will check with my multimeter.

So the battery/cable temperature has nothing to do with voltage reading? It should slow down the current but shouldn't affect the voltage right?

 

[JeremyH]

Temperature of the wire wont effect voltage reading just current draw of acessories

 

[csamsh]

So the battery/cable temperature has nothing to do with voltage reading? It should slow down the current but shouldn't affect the voltage right?

The half-cell reduction potentials upon which batteries are rated for voltage are at standard state (298.15K). I don't know exactly how temperature-dependent they are though.