What's considered good battery volts?

mosaud1998

mosaud1998

Joined
Nov 12, 2020
Messages
946
Location
Chicago, IL
I'm getting different answers from battery voltage charts. I charged my battery to full charge (per my trickle charger). I hooked up a scan tool to the OBD port and it read 12.14V at "full" charge. Does that mean my battery is bad? A fully charged battery should be 12.6V from my understanding. My battery is close to 5 years old.
 
ripcord said:
Lead acid batteries will have lower voltage in cold temperatures, but 12.14V after being charged is pretty weak. I would expect to be battery shopping soon.
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WEelp, looks like it's time for a new battery. The OE BMW one lasted 7 years. This one hardly lasted 5
 
A battery which is atleast 12.6v is fully charged, anything less is either not charged or defective. 12.1 is just about dead.
 
mosaud1998 said:
WEelp, looks like it's time for a new battery. The OE BMW one lasted 7 years. This one hardly lasted 5
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3-4 years is the expected lifespan of an aftermarket battery. 5 years is gravy. Anything more is borrowed time.

Some OEM batteries are garbage and some last forever. You really can't use that 7 years on the original as a realistic way to measure the quality of its replacement.
 
That 12.7 is the no load voltage of a battery at 70 degrees at rest which is no load for 6 hours.

I noticed that they stopped offering good discounts on batteries now. Pepboys is down to 15% and some codes don't work on batteries at Autozone/Advance Auto.

Had a super cold day and hadn't really been driving my car that much. Had it down to 11.2 and it wouldn't start. Took it out and charged it up. Voltage was 12 once it was disconnected. Could only get it up to 12.43 volts after fulling charging it indoors. Back in the car, it dropped back down to 11.9 volts. Usually the lowest it goes is about 11.5 volts.
 
mosaud1998 said:
​
I'm getting different answers from battery voltage charts. I charged my battery to full charge (per my trickle charger). I hooked up a scan tool to the OBD port and it read 12.14V at "full" charge. Does that mean my battery is bad? A fully charged battery should be 12.6V from my understanding. My battery is close to 5 years old.
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Did you maybe have the door open and a dome light on?
 
mosaud1998 said:
​
I'm getting different answers from battery voltage charts. I charged my battery to full charge (per my trickle charger). I hooked up a scan tool to the OBD port and it read 12.14V at "full" charge. Does that mean my battery is bad? A fully charged battery should be 12.6V from my understanding. My battery is close to 5 years old.
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I will say that on my Toyota the voltage at the OBD port is significantly lower than voltage at the battery, plus you have things powered up with the key on when checking voltage at the port.

That still seems low though. Check it at the battery with key off and doors closed.
 
Yes, your battery is almost done. I have a new battery that is almost consistently 12.6 and a 4 year old one that is about 12.1 but never less than 12. In my experience if it stays above 12 you can still start. Once it goes below 12, do yourself a favour and get a new one. You can top up your charges with a maintainer or charger but that’s just screwing around.
 
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On a modern car I would only measure voltage at the battery or jump start terminals and only when you are sure the car is asleep. Just opening the door wakes the car up and it will pull anything up to 8 amps for a period even after you close the door. That's enough current to pull the battery voltage down several tenths.

Even if they are not AGM, a modern low maintenance battery in good condition should have a rested voltage when fully charged of 12.7 volts.
 
barryh said:
On a modern car I would only measure voltage at the battery or jump start terminals and only when you are sure the car is asleep. Just opening the door wakes the car up and it will pull anything up to 8 amps for a period even after you close the door. That's enough current to pull the battery voltage down several tenths.

Even if they are not AGM, a modern low maintenance battery in good condition should have a rested voltage when fully charged of 12.7 volts.
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I might just take the car to Advance Auto or Autozone and have them test the battery along with the alternator. After this below freezing weather passes
 
Chris142 said:
Many people do not know that a battery is considered run down or dead @12.2v. Many people think 0 volts is where a dead battery should be.


Assuming that the volt meter you have is correct and the battery was charged the battery is bad.
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I mean, I used an OBD port. It might not be that accurate honestly.
 
mosaud1998 said:
​
I'm getting different answers from battery voltage charts. I charged my battery to full charge (per my trickle charger). I hooked up a scan tool to the OBD port and it read 12.14V at "full" charge. Does that mean my battery is bad? A fully charged battery should be 12.6V from my understanding. My battery is close to 5 years old.
Click to expand...
you need to test with car fully off no lights , and test it at the battery with a multimeter or at least a battery charger with voltage readout.

you will probably lose .3 to .5 volt testing with obd and car on.
 
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