Solar on engine hood?

wandererr

Adventurer
Started a topic in the jeep forum regarding solar panel on a JK hood. I have some questions though that transcend the jeep so I figured I'll post up here:

Has anyone mounted a flexible solar panel on their hood?

Did you discover any heat issues with hood not dissipating as much?

Did you discover the panel being affected by the hot hood?


Anyways - I measured and it looks like I might be able to put on there a 75W, maybe even a 100W flexible panel. Trying to figure out if it makes sense to do it or not.
 

OllieChristopher

Active member
This is becoming a popular trend for over-landers. I do not see the engine heat effecting the panel at all. As long as the underside is insulated you should be good to go.

I personally think it is the lamest looking thing right up there with a snorkel. OTOH it's not my rig so all that matters is you like it. A small portable suitcase panel would serve the purpose much better. I let my alternator do the charging while I drive and it takes less than a minute to deploy my Rockpals.

Solar panels on hoods have zero functionality over a portable solar setup that can be moved around to grab more sun.
 

highwest

Active member
I think Cascadia 4x4 offers a ready built solution for this. No affiliation, but certain applications look pretty slick.
 

coastalcop

Active member
Yes, working fine so far (where ambient temps in the 90-100s with surface temps much higher . BUT only a couple months of testing so far. Mounted two 50w flex panels to the hood in parallel. And I agree with the above poster indicating that a portable setup is more flexible. But I can leave the truck at camp and go hiking without worrying about someone schlepping off with my portable solar, which is a benefit.solar.jpg
 

Herbie

Rendezvous Conspirator
I'd love for someone to do a true A/B test with a pair of same-make panels - one on the hood and one off, just to get a sense of any change in panel efficiency. The panels will absolutely make power even when they're hot, but the math says they make a lot less, so I'd be cool to see the real-world impact.
 

emulous74

Active member
Boss Watt recommends mounting them with project plastic (cardboard) underneath them and then using some very strong tape, they have videos on youtube, it's said to prolong the life of the panels to dissipate the heat generated by the panels.
 

2.ooohhh

Member
I have 110w of solar on my land rover's hood. I've been running my 50qt ARB fridge and maintaining my starting battery off my hood solar for nearly 4 years now in two different vehicles. Previously on my FJ(80w) and now in the rover (110w). IR temp readings after driving /sitting in the sun don't read any higher similar owners of these panel's report being similarly mounted to their sailboats out in the sun on the open ocean.

sure portable panels that can be placed in a better spot for the sunlight might be more versatile in some situations but I'm happy to be able to park at my work, my home, or a local trailhead and come out to a cold drink and a hot battery without having to put my panels in and out of the truck several times a a day
 

roving1

Well-known member
I'd love for someone to do a true A/B test with a pair of same-make panels - one on the hood and one off, just to get a sense of any change in panel efficiency. The panels will absolutely make power even when they're hot, but the math says they make a lot less, so I'd be cool to see the real-world impact.
To me the issue isn't heat is bad (obviously it is) the issue should be is the heat on sheet metal in the sun of the hood more or less the same as the roof, and if it is what difference does it make? Going to be losing efficiency in both places the way you mount a flexible panel.

To really make the test you need: 1 A cold soaked vehicle in a shelter under a battery load. Then roll it into the sun and see the capacity. 2 Then leave it in the sun until the temp stabilizes from the solar load and see what the capacity is. 3 Then go heat soak the engine and see what the capacity is.

I think the big drop in efficiency comes from between step 1 and 2 in the hypothetical test not 2 and 3.

The thing I don't get is, whatever the efficiency drop is, being on the hood with a hot engine lasts a few hours right after a long period of alternator charging and then goes away for as long as the vehicle is off. So how is it remotely a factor? You lose efficiency at a time when you least need it temporarily and then for days on end as you sit in camp everything is as good as it could be otherwise.

I don't have anywhere else to mount the panels and I don't want to deal with storing temp ones so for me it's a moot point but I am curious just for science what the actual results would be. I suspect and intuit the hood isn't as bad as everyone thinks nor do I think the efficiency drops that much because sheetmetal and panels in the sun get really hot regardless. But I would love to know actual facts either way too.

I was a lot more dubious on hood mounting and heat soaking right up until I burned myself for the 10th time working on my panels on a vehicle that had not been run in days. Burning myself on the hood. Burning myself on panels lying in the grass. Burning myself on panels that had been hanging just by bungies in the air. Clearly most people have no idea how hot this stuff gets just from the solar load alone. Install these things in the sun on a 90 degree day with no shade and you will began to question how much extra heat the engine is really adding to the equation like I began to.
 
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roving1

Well-known member
IR temp readings after driving /sitting in the sun don't read any higher similar owners of these panel's report being similarly mounted to their sailboats out in the sun on the open ocean.
This makes me happy to hear and feel justified in my thoughts.
 

mep1811

Gentleman Adventurer
The heat issue is related to the solar controller.
Summer temps plus engine temps overheat the controller.
I solved that by mounting the waterproof controller on the bumper.
Be sure to mount with the heat sink out so it can dispel heat.

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