I have a 2000 Protege and the battery shows a voltage of 15.8 with the enging off.With the engine running it shows 17.2 volts. Is this normal?Seems a little high to me. I had the battery tested and it came back in good condition.Concerned. Thanks

 

There is no way the voltage can be 15.8V with the car not running. It should be about 14.5 volts with the engine running. I think your meter is faulty. Try another meter.

 

Agreed. You have a faulty or mis-adjusted meter.
If your battery is being over charged the easiest way to tell is look for evidence of battery acid on the top of the case. Also after running for a time, you should be able to smell the sulfides literally being burned out of the battery. It should "smell" like acid.

 

Nothing wrong with my meter. Tested it on my truck to see and truck battery shows 11.8 volts not running and 13.2 running. I retested the protege and i got the same readings. No wet marks on battery and it hasn't swelled at all. So back to my original question then. Alternator is over charging battery so I guess i'll get it rebuilt.

 

Under those conditions, its strange you are not seeing or smelling battery acid?
I'm confused, but perhaps putting on a rebuild is the best way to tell or it'll burn up your battery in short order, then you'll need a new one of those too.

Please let us know what happens.