12V voltage drop dual battery camper installation

[Yek88998]

Hi there

I can't wrap my head around a problem I have when trying to connect my dual 12v battery system in a camper. When I plugged in my VSR ( Orion from the brand Victron) i measured the + input was 3 volts although engine running (and app saying 14v input...). I thought the wire were too long so i pulled the red wire in between batteries out of the path i have led it into to check the wore was not damzged. Wire was ok so I mesured the current straight at the end while the other end was on battery and it read the same. So i put the wire back in, from the hood down the Stirling wheel up the driver side all the way then back down a wall behind drivers. And surprise when i tried to connect again to front battery it went back to reading 3 volts instead of the 12.8 v of the battery when engine is off! I even tried with a different cable and it does the same, current is the same until i put the wire "in place". I don't understand how the direction/ path of wire can cause that, it is beyond my understanding so I am seeking your help !

The thing is I did this same installation on the exact the same car and had no problem in the past.

Any feedback is welcomed as I am losing it haha.



Thanks,

Yasmine

 

[Lucien Nunes]

What wire are you talking about... the feed from the vehicle battery to the VSR?
How long is the wire and what size (mm²) is it?
Where is the VSR located? Have you checked its ground connection?
Where is the service battery located and what size is it?

 

[Yek88998]

What wire are you talking about... the feed from the vehicle battery to the VSR?
How long is the wire and what size (mm²) is it?
Where is the VSR located? Have you checked its ground connection?
Where is the service battery located and what size is it?

Hi Lucien. I have found the problem
My house battery was not grounded that is why. Didnt know the aucilliary battery needed to be grounded !
Thanks for the help