what voltage would one expect to see in an automotive battery that was fairly new and fully charged?

There are 6, 2.2V cells 6x 2.2 = 12.6V

That is fully serviced, charged up, and cool, at "rest."

The surface charge having been drawn off.

At 70 deg F a 12V lead acid automotive battery has a specific gravity of

1270. and that is the measurement for "state of charge"

It is used by professionals because the volts are so relative to circumstance. The temp and circumstances have a reference you can refer to, you can check your data, see where it would be,

Some use predictive meters.

They let your alternator charge your battery as you leave.

You leave with a battery not fully charged, but not overcharged.

Those who do not use it are aware of factors that cause changes and mentally factor it into their understanding.

Some who misjudge and misdiagnose forget.

Then their answers to the same questions can vary,

But generally, they can still get pretty close,

It takes time to isolate and get numbers down dead to rights

for a diagnosis.

It takes years of experience and mistakes to understand how you can get askew by being hurried.

If noone is paying the clock time?

Spending the time is spending his own money.

He probably has a new book that lets him off the hook for

The information, he says he does not need it.

He sells alot of parts and batteries.

That is the object.

A battery hydrometer is inexpensive. it is faster.

it is most accurate. Gloves and proper safety containers and distilled water available are inexpensive.

If you trust just anybody to work around it it can be a mess.

They work for lower wages and do not complain.

12.6V is your answer, and now you know why there are so many different ones given on this webpage.

It depends what it's doing. If it's an unsealed/maintenance type 12V six cell starter battery:

If it was open circuit voltage (without surface charge) perhaps 12.6-12.8V. (surface charge might add perhaps 500mV or so after a few mins).

If it was connected to a healthy alternator and running charging system: 13-14.5V (depending on accessory loading).

If it was connected to a load tester: Anything above 9.5V whilst under load.

If it was fairly new, fully charged and I managed to hurl it over the guard nets of the Empire state building onto solid pavement below: Exactly 0.17V, dropping by precisely 100mV every five seconds. Until Kate Moss Finds a job. Then it would increase by exactly 99.7mV per five minutes.

Voltage is only half the story when testing a battery. Even a shitty battery can claw it's way to 12.6V if charged long enough. But when under any significant load, it's voltage would drop faster than a hooker's knickers. Whereas a battery in good condition can also read 12.6V, and also be capable of outputting significant energy under load.

About 20

initially you will find aprx 13 volts. this is called a surface charge and does not actually represent to the true voltage. Once a slight load has been taken off of it the battery should be slightly than 12

Fully charged with no load it should read 13.2 V. If it is connected to a car it is under a small load from lock sensors, ecu etc and will read slightly lower. A fully charged cell is 2.2 volts. There are 6 cells = 13.2V

If it's because you wanna buy a used battery be careful, the battery might show 12.6 volts but does not mean it is a good battery. It has to be able to give a load for a given time, we usually check this with a carbon pile.

The battery has a CCA (Cold Cranking Amps) rating we load the battery to half of it's CCA so if it's a 850 CCA battery we load it to 425 Amps for 15 seconds the voltage cannot drop below 9.5 volts.

With no instruments it's harder to diagnose the quality of a battery.

I would like to see 12.6V in a fully charged battery. I also have a Midtronics battery tester and I'd like to see the measured cold cranking amps rating match the rating printed on the battery.

Between 12-15 volts

A tad over 12 volts. I have one I just recharged on the bench and it is at 12.76 volts with my meter.

The theoretical voltage of a lead acid battery is 12V for 6 cages and 2V for one cage. These are general voltage ranges per cell:

Open-circuit (quiescent) at full charge: 2.10 V

Open-circuit at full discharge: 1.95 V

Loaded at full discharge: 1.75 V

12 volts