What's a *normal* battery surface charge voltage reading?

I'm just trying to get a sense of what's "normal" for my truck. I have a 2004 Tacoma, Extended Cab, 2WD with the 2.4 motor.

If my DMM from Harbor Freight is accurate, my battery measures 12.38V with the motor off. I drove to work (about an 11 mile trip), turned off the motor and immediately measured my battery voltage and it then measured 13.26V.

My battery is a DieHard that's probably 3-4 years old.

Thank you,
Ed

 

Your voltage is normal.

 

Thank you.

Do you know of any documentation that references "normal range(s)"?

Ed

 

Your in the normal range for a 4 year old Ed. Those numbers look great. Good battery and alternator,,since they both affect each other.

Hard documentation would be associated with your group size and what Sears/Diehard expects out of it.

 

That voltage is fine...but...

Battery voltage collapses under load very easily if the battery is worn or damaged or old... So a load test needs done to assess how much of the battery is actually still remaining to hold capacity and provide that voltage and current output when needed. I believe autozone will test for free. Once the battery actual CCA rating hits only 200-300 amp capability (at least for 6 cylinder vehicles), start shopping around for a new battery (or just buy a Walmart MAXX or Interstate or other best level 'Gold' battery...they are all from Johnson Controls, just different types of warranties), and replace at your convenience. If the CCA rating is less than that, then your risking getting stuck somewhere and that's not worth putting off the purchase. Battery is one of those components that's not worth squeezing every single pennies worth of use from.

 

Computers like 12 volts or higher. Once the battery starts putting out less the vehicle will act like it needs a tune up. Skipping, bogging etc.

 

Mine is a year old on my 16 and reads out around 13.85v-13.90v.

 

Nope. Almost.
The computer in a automobile is a LOW voltage device. Sending (fuel injectors )and receiving (O2 sensor) LOW voltage signals to and from various sensors. The engine accessories operate on 12v (e.g A/C compressor clutch).
Your description is perfect for a carburated motorcycle/ATV with a bad/low voltage battery to where the coil needs a strong 12 volt voltage to supply adequate spark to the spark plug/s.

 

My original AC/Delco Pro hit above 14v when fully charged near the end of it's life(9ish yrs). The next A/C Delco Pro I bought to replace the original did not get above 13.7-13.5 it's entire life,,and it's life was shorter(7 years). Maybe the alternator was getting a bit weaker by then. Maybe I had more load on the system. Maybe the battery assembly plant changed countrys. Lots of variables.

Have started computer vehicles that have been pulled down to high 10 volts before. They weren't happy and barely ran,,but they did start on there own. My Chevy Geo Tracker with the 2.0 motor being one of them.