First of all, welcome to Stovebolt, where the inmates are running the asylum! Do you have a generator, or an alternator as a charging system? That voltage is WAY too high- - - -it will fry the battery in short order unless that problem is corrected. Charging system voltage against a fully charged battery should be no higher than 14.5-14.7, lower if the battery is slightly discharged. It also appears that the ammeter might be connected backwards- - - -which is a very simple fix once the high voltage problem is addressed. Help us out with a few more details about the electrical system, and one of the resident spark chasers should he able to help you sort things out.
Jerry

"It is better to be silent and be thought a fool than to speak and eliminate all doubt!" - Abraham Lincoln
Cringe and wail in fear, Eloi- - - - -we Morlocks are on the hunt!
There is nothing noble in being superior to your fellow man; true nobility is being superior to your former self. - Ernest Hemingway
Love your enemies and drive 'em nuts!