Why does my battery Gage go up and down?

Why does my battery Gage go up and down?

Sometimes it will sit at 11.5, sometimes at 14, sometimes at 16.5. It will sometimes adjust itself while driving, but the truck seems to be running without a problem. I haven’t had the battery tested, but I’m wondering if the symptoms above give any indication as to what the issue might be. Faulty gage? Battery issue? Alternator issue?

What makes my voltage gauge read low when battery is good?

When the vehicle speed is above approximately 24 km/h (15 mph), the engine/generator RPM is high enough and the generator current (amperage) output is sufficient to supply the current (amperage) requirements of the vehicle as originally equipped and recharge the battery. 1.

Where does the ECM tell the alternator to charge?

The ECM tells the alternator to charge or not. Also, check the pink wires on the body relay box under left hand side of dash. As well as ignition 1 fuse. One other thing is to check the battery junction box for loose or cut wires near engine on left hand side.

What should the voltage be on a car alternator?

12.6v is the optimal battery voltage. 13 -14v is the average alternator output. Depending on the load on the electrical system, anything higher than battery voltage is good voltage for a vehicle. Current is a different story.

What should the voltage be on a GM alternator?

GM typically runs a fusible link wire between them for overload protection and they can go bad, mimicking a bad alternator. A voltage drop of .25 volts or less is Ok and the alternator is bad. A voltage drop of .5 volts or more means the wire is bad.

What’s the battery voltage on my GM 05?

My 05 does the same thing with a new alternator and battery. In the city it is around 14 volts, when I get on the highway it drops to 11-12 volts. If I put all 4 windows up at the same time the lights dim for a second and then the voltage goes up to 14-15 volts.

Why does the battery gauge go back to 12 volts?

When your gauge read ~12volts and a new battery it went back to 15 volts, the old battery was overloading the alternator with an internal short. At one time I had a battery short bring it down to 9 volts and the computer went nuts. The engine back fired I just made it to a battery shop.

Why does the alternator drop down when the battery is charged?

The computer is constantly monitoring the battery voltage and as soon as the battery is charged, the alternator output drops down to match the current load on the system and it is no longer trying to charge a fully charged battery.