The volt gauge read 14.9 volts when the engine is operating.
If I test my battery with my multi-meter should battery voltage be 14.9? I say yes? Correct

 

When the car is running and you put the voltmeter across the battery, it'll read the alternator voltage.

 

If, in Fantasy Land, your voltage "gauge" is accurate. That'll be the day.

When the car is running, and the alt is charging, the voltage across the batt terminals will be lower than the voltage across the alt, by however much voltage drop occurs in the wiring. Shouldn't be very much; acoupla tenths of a volt, usually; butt check both. In a perfectly working car I'd expect 14.5 or so at the alt and around 14.2 at the batt after the car has been running for awhile after starting and the batt has gotten fully charged up. Let's say, 10 minutes of sitting idling in the driveway, for the sake of argument.

14.9 of REALITY is a bit on the high side. 14.2 - 14.3 at the batt, and a tenth or 2 more at the big terminal of the alt, is more normal. OTOH if what you're quoting is the dash "gauge", no telling whether it's accurate or not. Those things, when everything is working right, read whatever, and you just kinda get used to whatever that is; when something screws up, it's suddenly different. The absolute "number" the "gauge" shows is somewhat fantasy land. Normal vs Abby Someone is about the best you can hope for from those. Not, however many tenths of a volt. (or psi of oil pressure, ° of coolant temp, gallons of gas, etc.)

 

Exactly as Sofa said, if your lookin for accuracy, the meter on the RH side of this pic is where it's at......

 

That ain't no ****.....Wish I had one of those. Used them in Community College Trade Schools back in the mid 70s. Now I have a Fluke 77. Does the job...

 

I worked in a test eqpt lab in the 70s as an electronics tech. We were the warranty center for Simpson, Triplett, Weston, and this new company with a strange name, Fluke. I repaired many hundreds of Simpson 260s... I still have a few...

 

I've had my Fluke 77 for 37 years and it still works great...

 

I'm probably right there with you!!

 

I have a Fluke 8022 that I got in around 79 or 80 from that shop. Still somewhat works although the display is farkled and mostly illegible.

 

I love the old tools.
By the way I determined that my original alternator had failed. My multi-mater did the job

 

After seeing that pic of the Simpson Multimeter (the industry standard at the time), I had to post this piece of electronics history (pencil for scale):
Bought it in '58-'59, when I was about 10 years old from Olson Radio on N. High St. in Columbus Ohio. Olson had a number of retail electronics stores across the country, a competitor of Radio Shack. Don't recall how much it cost, but I'm sure it was far less than that Simpson! It still works just fine.

 

The alternator has failed & is at the rebuilder's.
Last Saturday, I stated the car & the alternator howled & voltage would go to 13 & then down to 12 & not charge more.