Flexible solar panels for the roof

[cbbr]

Anyone have panels on their roof? I am going to mount a flexible panel under my Gamiviti roof rack and wonder if there are any that fit better than others. I am posting here because fit is my primary concern. Looking for 200W or so.

 

[LJE]

Anyone have panels on their roof? I am going to mount a flexible panel under my Gamiviti roof rack and wonder if there are any that fit better than others. I am posting here because fit is my primary concern. Looking for 200W or so.

No experience with solar panels on vehicles, but DIY'd a 11kw system for the house. For what it's worth, any sort of shading (like the roof rack) will typically DRAMATICALLY lower overall output.

 

[dogdaysindurham]

I have a Grape Solar 50 watt flexible that is mounted on my hood that has held up great for 2 years so far. Mounted with marine grade 3M VHB tape. I believe the panel was made by SunPower. I run two 100 watt rigid Grape Solar panels that I’ve had for 10 years on roof of my 100 series / relocated to the roof of my RTT. They are still doing great.

I think they make a 100 and under the Maxeon line make a 330 W

Sunpower Maxeon Air 330W Flexible Solar Panel

Boaters, campers, RV owners rejoice - this monster 330 watt panel is of the highest quality. You can adhere it to just about any surface, even a curved surface. Each panel measures a ridiculous 80 inches long and only 31.5 inches wide. You can tile them on roof tops or other surfaces using 3M...

fullbattery.com

 

[dogdaysindurham]

Flexible panels are often used on boats. Some can have issues with delamination when compared to rigid panels.

 

[suprarx7nut]

FWIW, I count on a flexible panel on a car dying in 2-5 years. They're not quite disposable, but they're close.

I had one die on the roof of my LX (previous owner glued it straight to the paint). Seemed like it was only a couple years old. The hood mounted flexible ones have been notorious for short life spans as well.

If you have an option to do rigid I would go that route.

Seconded on the shading consideration under the rack. I'd look at a quick release rigid over a permanent flexible setup.

 

[cbbr]

On the over/under issue - I use the rack to haul stuff around. Its not just for show.

So the problem that I am trying to solve is the battery life in the heat while sitting around. I could probably just turn the fridge off, but then I wouldn't have cold drinks in the truck whenever. Its a pretty seriously first world issue.

The fridge draws +/- 50W when its hot so I figured that if I had 200W under the rack with a 100W output I could buy days worth of power. I have an 800W charger for when the truck is running which works great while I am driving the truck (rainy weather), but the truck can sit for a week at a time when the weather is nice.

I thought about a panel for the hood, but the Cascadias are just too expensive for me to buy every 3 years.

 

[suprarx7nut]

On the over/under issue - I use the rack to haul stuff around. Its not just for show.

So the problem that I am trying to solve is the battery life in the heat while sitting around. I could probably just turn the fridge off, but then I wouldn't have cold drinks in the truck whenever. Its a pretty seriously first world issue.

The fridge draws +/- 50W when its hot so I figured that if I had 200W under the rack with a 100W output I could buy days worth of power. I have an 800W charger for when the truck is running which works great while I am driving the truck (rainy weather), but the truck can sit for a week at a time when the weather is nice.

I thought about a panel for the hood, but the Cascadias are just too expensive for me to buy every 3 years.

I think your logic is sound. I would find a rigid panel (or two) to mount under the rack.

 

[LJE]

On the over/under issue - I use the rack to haul stuff around. Its not just for show.

So the problem that I am trying to solve is the battery life in the heat while sitting around. I could probably just turn the fridge off, but then I wouldn't have cold drinks in the truck whenever. Its a pretty seriously first world issue.

The fridge draws +/- 50W when its hot so I figured that if I had 200W under the rack with a 100W output I could buy days worth of power. I have an 800W charger for when the truck is running which works great while I am driving the truck (rainy weather), but the truck can sit for a week at a time when the weather is nice.

I thought about a panel for the hood, but the Cascadias are just too expensive for me to buy every 3 years.

It partially depends on the tech in the panel, but I'd be very surprised if you got 50w out of a 200w panel that had shading from a roof rack. The Gamiviti rack would likely cast shade across all strings inside the panel (assuming they're even broken up like that in flexible panels - they may just all be in one long series string of solar cells within the panel).

A shaded solar cell is more or less a resistor at that point, so every cell that is shaded is turning the power that the other cells produce into heat. Current (amperage) flows in series in each string, so if you shade a single cell of a string within a panel, all the current from the rest of the string still needs to pass through it. But, since it's turned into a resistor, that current just turns into heat.

A single panel catching partial shade on my roof will drop a 2640 watt series run of panels on my house's roof down to sub 500 watts, easy. It's the same phenomenon, just on a array-level scale vs panel-level scale in your case.

 

[cbbr]

I think your logic is sound. I would find a rigid panel (or two) to mount under the rack.

I have a couple of Eco-Flow rigid panels, but the fit is going to be very tight. I think that I will pop the rack off and put them under it in the yard tomorrow for a little "test run" to see how bad the output drops.

The Gamiviti rack sits close to the truck and the front is already raised. So the rigid panels will barely fit. My worry is that because they will be virtually against the rack, they will break. I love the rack, but they didn't design it for things underneath. I may have to rethink and just use a trailer to go get 2x4's....

 

[LJE]

I have a couple of Eco-Flow rigid panels, but the fit is going to be very tight. I think that I will pop the rack off and put them under it in the yard tomorrow for a little "test run" to see how bad the output drops.

The Gamiviti rack sits close to the truck and the front is already raised. So the rigid panels will barely fit. My worry is that because they will be virtually against the rack, they will break. I love the rack, but they didn't design it for things underneath. I may have to rethink and just use a trailer to go get 2x4's....

There ya go! A practical experiment will certainly tell you more than my (mostly informed) engineering guesses, hahaha.

 

[cbbr]

I have no doubt that you are correct, but I only learn the hard way. Probably why I'm so fond of old, modified vehicles.