Solar install - using ground wiring for pv neg

[Seaninnj]

Hi all

I'm in the planning stages of installing the panels and Victron 100/30 Smartsolar SCC to our system. The question is the RV came with the Solar Prep with a rooftop gland box. Behind the wall in our bedroom are 4 wires. 2 go to the rooftop gland box (red#1 and black#2). The other 2 go to the battery (red#3 and white#4). White#4 is supposed to be Black as per the attached but it seems they used spare white here.

The challenge is I want to mount the Victron SCC under the bed with the rest of the Victron gear. I have traced the Solar prep red wire (#1) to a spot that I can get to from under the bed. The challenge is that I have no way to get to white#4 as it goes to ground somewhere.

So..the question is would it be suitable to connect the PV negative (black#2) to the common ground (white #4)? Then I'd pick up the negative at the appropriate location on the negative bus bar under the bed to connect to the Victron SCC solar panel input.

I'm guessing the answer is NO but I figured I'd ask in case there was something I hadn't seen when searching the boards.

My next tactic would be to use the existing run of White#4 to pull through a pair of wires in its place.
I'm guessing it can bed done but I'm worried if I hit any snag then my existing run might be lost.

 

[Seaninnj]

Answering my own question after digging around for the answer. NO you should not connect PV negative wires to ground and use that to feed your SCC. Fishing wires it is...pray for me!

 

[pollenface]

Some dc-dc chargers are designed that way, you only connect the pv positive to the charger .... eg Ctek D250S, vehicle, battery and solar negatives are met at a common post.

 

[HRTKD]

When it came to the wires in my RV, I had to forget just about everything I thought I knew about wiring color. I swear these guys used whatever was handy at the time.

Direct connect from solar charge controller to battery is the way to go. The "exception" is that in more extensive systems, the cable from the solar charge controller goes to a set of common bus bars and then from the common bus bars to the battery.

 

[12VoltInstalls]

Direct connect from solar charge controller to battery is the way to go.

the answer. NO you should not connect PV negative wires to ground

I like home-run wired systems. Less fire, less hair pulling