Mounting Flexible Solar Panels

[oldtamiyaphile]

I'm about to install a pair of 180w panels to my van. My plan is to vinyl wrap my roof in chrome (chrome to help offset the heat gain of having a solar panel on the roof) then silicone the panels to that. That way if I ever want to remove them, I won't have messed up paint to deal with, just peel off the wrap

Here's a good article detailing various installation methods:

How many ways to install the flexible solar panels on the camper’s or caravan’s roof?

The main issue I have is cooling. Those panels get really hot. I'm looking for something like coroplast that would give me a bit of air gap but not just melt in the sun. The roof ribs are already fairly deep, so that's better than 100% contact, but on previous install I found that 10mm isn't really enough.

Any ideas?

[JockoT]

I like the idea of the aluminium rails in the article. Mounting to a set of roof rails would give an air gap and leave the vehicle standard (if it will take roof rails).

[Daox]

Do they make coroplast in a thickness greater than 10mm?

[freebeard]

Coroplast is an exemplar of a category.

https://www.google.com/search?q=doub...l+fluted+panel

Metal, polycarbonate, filled with insulation, etc.

[oldtamiyaphile]

First panel is done.

Chrome wrap, 10mm fluted polycarb (intended for roofing), panel on top. All fixed with VHB tape. I ran a strip of alluminum over the front of the panel just in case. It's screwed to the factory roof rack points (I have 10 mounting points so I can spare a couple).

Top Tip: Flute polycarb is much cheaper in short pieces than in longer lengths. A 2400 long sheet was $120, I bought 3x1200 sheets for $60. It means one join under each panel, not a big deal.





The temperature of my roof is the same under the panel as it is without, so happy with that.

So far I'm seeing approximately 0.2l/100km gain. Less than I expected, but then that's why I ordered two panels. I wanted to run a single panel for a while just in case the second panel wasn't necessary. As we head towards summer, the gain can only increase.

As the panel smooths my ribbed roof for only a tiny frontal area increase, I should have better aero too.

[seifrob]

It looks like you have broken links in images, at least i cannot see them. Still, sounds like great work. Did you delete an altermator, lessen the alt load, or is the gain you mentioned just from a better aero?

[oldtamiyaphile]

Images fixed

I have a factory 'smart' alternator so it automatically cuts back based on the panel input. If you have a 'standard' alternator, based on my previous panels installed on older vans, you probably won't see a measurable gain. My hope is with the second panel (360W) the alternator will only be providing a charge at night, lights on etc.

If that's not enough I have space to add a third panel across the front still.

I also have stop/ start, and with the panel it's able to activate about twice as often as it previously did. The second panel should mean stop start will work almost 100% of the time. I used to use an A/C charger once a week and that always gave me improved economy in the morning. Unfortunately the battery was already weak by the time I got into the city. I drive 90% city, 26km/h avg around 22km with 22 lights, so the stop start cops a beating. Renault say it's good for 400,000 cycles, I hope so. I do try to take the highway home once in a while.

Now when the engine switches off I can still see the battery holding about 12.6v with the A/C fan and radio, GPS, dash cams, drl's, stop lights etc running. Previously it would dip to 12.0 or slightly lower pretty quick.

The smart alt is pretty good, on a charged battery it will just sit on 11.7 volts while I cruise, only ramping up under braking, but as a hypermiler, there's not really much energy to recapture, so I find my battery is always pretty low. The solar panels seem to be helping at cruise I usually see around 12.0 now.

[oil pan 4]

Since I have actually have put these kinds of flexible solar panels on vehicle roofs I say just alattach the panel and leave it. Don't over complicate the situation.

Since you have solar panels why not unbelt the alt and disconnect field power?

[oldtamiyaphile]

Originally Posted by oil pan 4

Since I have actually have put these kinds of flexible solar panels on vehicle roofs I say just alattach the panel and leave it. Don't over complicate the situation.

Since you have solar panels why not unbelt the alt and disconnect field power?

I've heard of people scorching their paint when just attaching panels to their Sprinters. I have nice paint. I didn't have the FLIR back then but I know my old Mercedes van roof got really hot to touch with just the 10mm air gap from the roof ribs. With most of my roof now covered in panels, I really didn't fancy searching for something in the back of the van on a hot day. The panels should last longer too. The polycarb panels made the install simpler too as I cut them to match my roof ribs, then had a nice flat space to attach the solar panels to.

With a smart alt, all I really have is an idler pulley (with small windage losses), but I still have regenerative braking and no worries if it's over cast or night time. With a serpentine belt I'd still have to have an idler pulley. The van still has 4 years of factory warranty, so it's best not to mess with too much. Also, I'd probably loose the factory stop/ start, possible CANBUS issues, etc etc.