electrical issue

[bigger_george 2]

Well, my friend has recently been having issues with his electrical system. He currently has a red top and yellow top in the back. He reads around 14 volts up front but his battery in the rear (not isolated) reads at 12.5 volts?! The battery in the front and rear both read at 12.5 with car off. Any clue what could be causing this issue?

[splblazer98 1]

wiring problem would be my first guess....

[JimJ 11]

Is the auxiliary battery charging?

Sounds like it's not connected to the main charging system at all...

[bigger_george 2]

Yeah that's what I told him; i just said its acting like a distro block. So yes it's not being charged.

[bigger_george 2]

Well he disconnected the second battery and the amp reads at around 12.8 volts with HU at 0 volume. I'm starting to think its something else ...

[Aaron Clinton 2,372]

Well he disconnected the second battery and the amp reads at around 12.8 volts with HU at 0 volume. I'm starting to think its something else ...

[JimJ 11]

12.8V with the engine off?

The fundamental issue is that the second battery never was properly connected to the alternator. Wire it in parallel or use an isolator, and I guarantee this funkiness goes away...

[bigger_george 2]

that was with the engine on. It jumped from 14.2 to 13.7 to 12.8 then back to 14.2 with just volume at 0.

[Tirefryr 1,742]

HE has a MAJOR current draw issue somewhere, or something is loose in the alt, OR a slipping belt which will be more prevalent under load.