Pop top bolt length

[Belize]

I am going to use 1/8” angle aluminum to mount my solar panels on the pop top. What length bolt will I need if I avoid all the padding and bars below, just though the top and pop top ceiling?

[REF]

Personally, I wouldn’t put any holes in your pop top, just inviting potential leakage issues later on. There are some threads about this on the forum, with mounting solutions that don’t include drilling. One way I’ve mounted is with using 3M VHB tape on the underside of the aluminum angle, I cut a 36” piece down and used 9” pieces at each corner. I did this on our travel trailer, works great and is holding up well.
Do you have Yakima tracks running the length of your pop top? I’ve run angle aluminum anchored into those to support panels in the past when we had our SMB pop top.
If neither of these are an option, at the least, you should highly consider drilling into and through your pop top on the OUTSIDE of the canvass area.

[Belize]

I will probably still bolt through pop top, most likely on the outside of the canvas area. Any suggestion on the proper bolt length?

[Klompen]

I'm with REF on not wanting new holes in the top. Putting them outside the canvas sounds good, but remember that the canvas folds up into that void so bolts may wear holes in the canvas.

[Belize]

The problem with not bolting here is that the only adhesive available in Belize is 5200. And I know that once set, it is damn near impossible to remove.

[Grampswrx]

Just about anything under 3" will work if you are only going through the eave outside of the canvas. I have installed a ton of yakima feet outside of the canvas and their bolts are super long. The yakima widebody brackets come with 2.25" bolts.

The fiberglass is only about 1/4" thick, so a 1" bolt should be fine.

[Belize]

Quick question on bolting the solar panels to the pop top. Is it ok to bolt brackets to the sides of the pop top instead through the top? I am figuring this will alleviate and leak problems, but worry about the strength of the fiberglass along the sides of the pop top.

[Twoxentrix]

Unfortunately any hole in the roof becomes a "potential" problem. but if done correctly you minimize future issues.
As far as bolting to the sides of the pop top, it is a possibility for you - structurally I don't think it posses an issue since roof racks (weighing considerably more) are installed similarly:

[Gooseberry]

You can start with a 4” length and cut down.