Positive ground/negative ground and a solar charge controller

[herm0016]

i ended up with a "positive ground" solar charge controller. I have it all setup to charge the house battery and have my loads set up through a fuse block on the load pins of the controller. I am also powering some clearance lights with the truck trailer plug. the slide in camper has a chassis ground common to all the interior and clearance lights.

do i need to install a relay between the clearance light wire of the truck harness and the clearance light circuit of the camper? should be very straight forward to wire up. I can run a ground from my trailer plug to the tail lights to keep that circuit isolated from the camper circuit.

or... am i crazy, and i can just hook up the 12v hot from the trailer plug to the battery for charging and common ground everything and not worry about it?
controller is renogy PWM30CC w/ one of their 100 watt panels.

 

[tortillasoup]

http://forum.solar-electric.com/for...sitive-ground-vs-negative-ground-solar-panels

 

[herm0016]

Hmm.... as long as it works and charges the battery, and I don't measure voltage from chassis to ground ... everything is floating point anyway. I think I will install the relay just in case.

 

[tortillasoup]

It feels risky to me, why not get a negative ground charge controller? Did you get this off craigslist or something?

 

[herm0016]

It's a kit from renogy that was a good price. Mentions using it for an rv or home. Did not mention it was positive ground in the description.

 

[tortillasoup]

It's a kit from renogy that was a good price. Mentions using it for an rv or home. Did not mention it was positive ground in the description.

Yeah but that could just be a general copy + paste description with no real thought to it. I'd be tempted to return it and get something with a negative ground. I'd rather have a used item off ebay that is proper rather than a new item that is potentially improper. I'm not saying it isn't possible but it's confusing risky for anybody who isn't aware of the the positive ground situation.

 

[herm0016]

I really don't know why one would have to run it positive ground.... its all floating point anyway... I i have it wired as such right now and it is charging the battery fine, lights work etc... i don't have it on the truck yet or the tail lights/clearance lights wired. if i change it to positive ground (chassis connected to positive battery) Will i get a voltage when measured between the camper exterior and the truck bed? am i stupid and should just buy a different controller? ( and delete this thread so i can sell it to someone!) i will post a wiring diagram.