Not fully charging batteries

[Bengy88]

Hhow55 and rawze are correct. I spent 3 days in class for just batteries when i worked at ryder. if you can imagine that boring shi#t lol. There is ALOT more to a battery than voltage that you see.

Now with that being said my first step is to test my voltage directly at the alternator, verify wether it matches the guage or not. If it does then your problem is most likely in the alternator... Usually a bad or dead battery will cause an alternator to overcharge. If it doesnt match the guage then is possible your guage is shi#t but you should still check your voltage drop from the alternator to the batteries. Then from batteries to the cab. If you follow your circuit from one point to the next all the way down the line you will find the issue. Oh yea dont forget to check powers, grounds, and voltage at the starter.

An amp clamp and learning how to properly use one also helps in situations like low voltage and cranking issues. For future refrences