Hightop Van Flexible Panel Questions

[Len.Barron]

I'm moving through my build and want to start laying the ground work for solar on top of my 24" bubble top van, as it is already 10ft tall I don't want ridig panels that would increase that. Due to the size and shape of the available roof area 100w flexible panels (as many as 5) would be a good fit if I can stay with 42" L x 21" wide (give or take a 1/2") would be optimal. I already have a house battery system (dual group31s, dual alternator, manual isolation/combiners). I'm interested in panel, interconnecting cable, and controller recommendations for a 4 or 5 panel system.

 

[Len.Barron]

Before someone comments on my ground cable placement, that pic was early in the build and I moved it to the rear battery.

 

[Len.Barron]

From the bit of research I have done there are some new coatings that extend life considerably over earlier versions (ETFE vs PET) and of course some vendors build better quality stuff. No arguement that they probably won't be quite as efficient but I think lifespan differences from a panel that sticks up and gets tree branches smacked into it and one that fits tight to the top contour will make that a wash..

 

[luthj]

With 5 panels you are stuck with 5s or 5p unless you get a second controller. With 4 you may consider 2s2p config with a mppt controller. Good shade resistance, and higher array voltage. You should consider mounting the panels a AL sheet or composite sheet. Then isolate it from the roof with thin insulation or air gap. This keeps the vehicle much cooler, and makes replacement easier. Bonding to a rigid backing can really improve flexible panel life.

 

[Len.Barron]

I was just reading about how best to connect them; I am leaning toward a 4 panel system that is 2S/2P, also agree on some thin backing, I was looking at some thin perforated plastic to isolate/air gap them a bit, still looking at what is available...appreciate the input!

 

[luthj]

If you're looking for short panels, it is possible to purchase frameless solar panels. These have the same glass face but no metal frame around the edge. They are available in various thicknesses of glass. It can be hard to find, but can be mounted much closer to the roof surface by virtue of their thinness.

Have seen reports of some folks removing the extruded aluminum frame from solar panels as well. although I've never done this myself so I cannot speak to its ease or suitability.

Given that these frameless panels have roughly the same life as a framed panel, it would make sense to permanently bond these to the roof. Units with thinner glass are slightly flexible and can be bonded on a curve. Although most frameless panels use thicker glass and a design for rigid mounting.

 

[Len.Barron]

My hightop roof has a lot of contour so flexibility is very much desirable.
Looking at these panels: https://www.amazon.com/gp/product/B017N7BRX6/ref=ox_sc_act_title_5?smid=A3QUWC2QIV3WZF&psc=1
And this controller: https://www.amazon.com/gp/product/B077HHYYHT/ref=ox_sc_act_title_1?smid=A2WI2LFG1JAJEM&psc=1
and these to isolate them: https://www.usplastic.com/catalog/i...0zFowG3Jo9DGWaOSaIA_boCAzA9078d8aArjoEALw_wcB

2S/2P set up would seem to make the most sense.

 

[luthj]

The solar panels look alright. Make sure you do a short circuit current test on them (with your meter) in full sun. Compare them all to each other. It is not unusual for the cells to get micro cracks in handling/shipping. Avoid repeat bending, or dropping anything on them. I suggest bonding them down with some sikaflex, VHB tape, etc. Note that those panels don't likely have bypass diodes for each string (no room as they don't have a normal hookup box). This will reduce output in partially shaded conditions. It may not be a big deal for your usage though

The solar controller looks good. It has fully programmable setpoints. Make sure to follow your battery makers published specs.

The PP sheet will do the trick I think. I would seal the leading edge with some flexible sealant, just to keep crap from getting blow under.

 

[Len.Barron]

I plan on sealing them fully around with eterna-bond tape...that stuff is bullet-proof..

 

[dreadlocks]

I bought some of those panels, they fell apart pretty quickly.. within 2 years it was junk and I stopped using it, one is still mounted to the top of my lil trailer tho.. here's a crappy night shot of how its held up over last ~4 years.



IMO Go Rigid or plan on these flexible things being disposable..

 

[Len.Barron]

I bought some of those panels, they fell apart pretty quickly.. within 2 years it was junk and I stopped using it, one is still mounted to the top of my lil trailer tho.. here's a ************ night shot of how its held up over last ~4 years.



IMO Go Rigid or plan on these flexible things being disposable..

if they were going on 4yrs old they would have had the PET surface coating, I have read that most reported short life with that. Unfortunately the ETFE coated panels don't seem to have been out long enough to make an apples to apples comparison..