Solar set up question.

[Alontheway]

Depends on what kind of roof you have as to how to attach. I would only use screws for a rubber roof. For fiberglass, aluminum or steel roof you can use only the Lap sealant, or actually use VHB tape to tape the gland on, then seal it all up with Lap sealant. The fewer needless holes you put in the roof the less likely to have a leak, and I know you are putting a hole for the wire right there, but not using screws is a few less holes.
Self leveling Lap sealant.

On the ground... what is the fear here? 12 volts is not going to do anything to you. The battery negative is ground, so technically things are grounded. The trailer is not grounded unless plugged into an outlet, so in another way, there is no ground when not plugged in.

 

[Euls12]

Depends on what kind of roof you have as to how to attach. I would only use screws for a rubber roof. For fiberglass, aluminum or steel roof you can use only the Lap sealant, or actually use VHB tape to tape the gland on, then seal it all up with Lap sealant. The fewer needless holes you put in the roof the less likely to have a leak, and I know you are putting a hole for the wire right there, but not using screws is a few less holes.
Self leveling Lap sealant.

On the ground... what is the fear here? 12 volts is not going to do anything to you. The battery negative is ground, so technically things are grounded. The trailer is not grounded unless plugged into an outlet, so in another way, there is no ground when not plugged in.

Wood frame. Rubber roof.

Would you RECOMMEND going screw free with the rubber, too? Or just for fiberglass, steel, or aluminum?

I was planning on doing 3 panels in series on the roof. Voltage would be a lot higher than 12v.

I found this article recommending grounding the panel frames to the chassis. Said it's a requirement. That's why I was asking.

Do RV Solar Panels Need to Be Grounded? – Camping Fun Zone

campingfunzone.com

 

[Alontheway]

The problem with the rubber is that is is flimsy and not sturdy enough to hold anything. With metal or fiberglass you can attach right to that. On rubber you have to attach the the underlaying wood, so unfortunately this means screws penetrating through the protective rubber layer. No worries as long as it is maintained.

Interesting article. It did not mention how to ground the RV, or maybe, is the RV sufficient enough of a mass of steel to absorb all the juju?
So, ground your panels to prevent shock from some buildup of current? Where actually is the current building up?

 

[Euls12]

The problem with the rubber is that is is flimsy and not sturdy enough to hold anything. With metal or fiberglass you can attach right to that. On rubber you have to attach the the underlaying wood, so unfortunately this means screws penetrating through the protective rubber layer. No worries as long as it is maintained.

Interesting article. It did not mention how to ground the RV, or maybe, is the RV sufficient enough of a mass of steel to absorb all the juju?
So, ground your panels to prevent shock from some buildup of current? Where actually is the current building up?

Screws it is. Thank you.

As for where...

I read a number of conflicting statements in different articles, that's why I was asking for an opinion here.

It's moot now anyways. Decided against series, going with parallel. Had two panels on the ground in series... One was damaged this week and I had to rewire the remaining one. If anything happens to any of the panels on the roof, I don't want to have to do the same thing. A lot more work.

Thanks for the info. Have a good one.

 

[Alontheway]

On the roof you will not be moving it or kicking it or tripping over it. I would put worry-about-damage way way down the list of concerns and pritoritize the higher voltage. Repaires are easy as you saw. To each his own though.
As to where. Away from things. AC unit will shade it at low sun angles as will an open roof vent lid. Mount them as close to the batteries otherwise.
good wishes...