I recently got a 100w lensun semi-flexible panel for my land cruiser, replacing a 45w system. The specs showed and said that the panel can be mounted with the 4 eyelets at corners or with adhesive to a RTT, roof, whatever. ? is there is an amazing amount of heat so much that IMO any adhesive would fail. My roof is an aluminum skin, panel on top, no adhesive, it is like a big heat sink but still the underside of skin under panel is hot as H - is that normal ?
Flexible solar panel mounting (1 Viewer)
- Thread starter peesalot
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^ I take it that was a dig about the lack of response so far to your post.
I'll just say that I saw your post earlier, looked at it and found it unclear, so did not reply. Maybe reread and clarify what the actual tech question is?
I'll just say that I saw your post earlier, looked at it and found it unclear, so did not reply. Maybe reread and clarify what the actual tech question is?
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- #4
Heard, Trying to determine what real world results are for heat generated by flexible solar panels mounted on flat surface, ie - hood, roof, RTT, etc....
I did some research and it appears that even tho manufacturers claim it is ok to mount with tape or adhesive to a surface that an air gap is beneficial if not necessary. It made the alum. skin roof quite toasty with no air gap. I appreciate your response.
I did some research and it appears that even tho manufacturers claim it is ok to mount with tape or adhesive to a surface that an air gap is beneficial if not necessary. It made the alum. skin roof quite toasty with no air gap. I appreciate your response.
Rigid panels perform better when there is an air gap. I'd think flexies would also.
Except that most flexies I've seen were glued to the hood of the vehicle. Which in my mind would make them hotter than they would otherwise be. But, the owners of those panels claimed that they output their rated current even in the hottest conditions.
So maybe quality flexies have an advantage in that area and require no backspace (air gap). Tho I would surmise that at least they would last longer with one.
edit: as far as what adhesive to use with them (most I've seen come with adhesive already applied)...I guess the question then is would you want to remove the panel at some point without damaging the underlying surface?
If so, then recommend a double-sided outdoor tape (3M probably) applied only along the outer-most edge of the panel all the way around. Along the trailing edge (or at the corners on a curved surface) I'd leave some gaps to let air and moisture in/out.
Otherwise, liberal application of Toyota FIPG103 over entire backside and roll.
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I've had a flexible 175w panel affixed to my RTT with 3m VHP tape for about a year. This is my second summer in the Texas heat with it. It stays parked outside sometimes for several days at a time in 100+ degree temps and direct sunlight. Still working great so far. I tug on the corner every now and then and the adhesive tape seems as secure as the day I put it on.
Covers up that ill advised sunroof?
3M VHB. I just did a Cascadia 4x4 system on a JK Jeep with their kit. It was just 3M VHB that was used on the panel. It's not coming off without some significant work.
LC 100 Example
LC 100 Example
I attached a 100 w flexibale panel directly to my RTT and it failed after two years.
The performanace of flat panels are very negativley affected by heat.
Last winter I removed the old panel and reinstalled a new panel, with better heat resistance, onto twinwall corrugated acyclic panel, with 3/8th by 3/8th ribbing for cooling. The new panel says it is more heat stable than the early generation ones.
The new panel works well.
Lessons to learn:.
The performanace of flat panels are very negativley affected by heat.
Last winter I removed the old panel and reinstalled a new panel, with better heat resistance, onto twinwall corrugated acyclic panel, with 3/8th by 3/8th ribbing for cooling. The new panel says it is more heat stable than the early generation ones.
The new panel works well.
Lessons to learn:.
- Do not used 3M mounting tape, its permanent and it took me 5 hours to remove.
- Use only Gorilla mounting tape, it’s still very strong, but is easier to remove.
- Mount the thin solat panel on a cooling substrate (acyclic panel) for airflow as in a solid panel in a roofrack.
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- #11
Copy that, 2 issues arose. 1st. when traveling 80mph on freeway the panel tends to flap if not glued, tore corner eylets out, if mounting at corners with hardware some sort of adhesive needs to be in center to keep from flapping at speed. Heat - at Rubicon in full sun the panel would shut down by 10:00 am, had to park in shade to get system back online, there is definitely a heat threshold that shuts it down. Mine is mounted on aluminum roof skin with an air gap, clearly not enough, need to remount with better air gap substrate. How will that acrylic deal with the UV ? I am looking at various air gap material, find it hard to believe that the panel manufacturers don't have air gap set ups available, they are losing a good income source and detracting from their panels performance by not providing an optimum air gap mounting platform.
that's interesting, I have not heard of a panel that shuts down when hot. What does that mean exactly? Is there a temp sensor on it?
The efficiency of a PV panel decreases with increasing temperature, of course, but I don't know of a reason to shut it down when it gets hot, it's not like a normal panel is going to get damaged instantly, as far as I know.
Maybe some side electronics issue?
The efficiency of a PV panel decreases with increasing temperature, of course, but I don't know of a reason to shut it down when it gets hot, it's not like a normal panel is going to get damaged instantly, as far as I know.
Maybe some side electronics issue?
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No issue other than I noticed the charge indicator on controller was off, didnt have a volt meter to check panel output, relying on indicator light on controller, soon as I cooled with water or moved to partial shade it came online. and in evening it would come on as dusk approached, provided enough power , gauge always said 12.5 or better, I will meter the panel when the charge light is off in full sun and report findings. Oddly enough, the charge indicator was on when there was almost no sun in morning and evening and when in shade during day it was on.
it is very likely something to do with your controller. The panels I have seen don't make decisions like that on their own, but eh, everything is possible. Maybe a setting or an overload protection on the controller? Is it possible that what you attribute to temperature may just be that there was lots of power produced at that time, also when the sun was brightest? Maybe the battery was fully charged at that point? My controllers don't ever shut things down during the day, even if the battery is full, but they are good MPPT units with multi-stages charging algorithms.
If there is no display on the controller and you're not talking about large voltage and current, I would suggest to get a little power meter that you put in line, $20 or $30, very interesting to see what is going on. Helps with panel orientation too.
If there is no display on the controller and you're not talking about large voltage and current, I would suggest to get a little power meter that you put in line, $20 or $30, very interesting to see what is going on. Helps with panel orientation too.
I, too, in 15+ years of using different types and brands of solar panels apart of keeping various battery systems happy in our explore/camp rigs, have never experienced, nor heard of, a solar panel and/or controller shutting down the flow of current with the exception of high/low temperature of LFP batteries and, of course, when the battery was at or above ~80% charge capacity.
Not fully related to this discussion (unless the OP is using a Victron) but as a data point for controllers shutting down as its mentioned in the post above...I've had my Victron 75/15 shut down a number of times in hot weather in my BJ74. Took me by surprise on a hot summers day when I checked things on the app and discovered this.
I've a Victron 100/15 in 80 and it has never shut down.
The BJ74 is a fishbowl in the sun when locked and windows up. Factory glass tint in the BJ74 does little to block the rays. Having all windows done with a modern tint would likely help considerably. I've a temp gauge in a power port on the dash and have seen 60C with the vehicle parked in the sun, when it's in the 20/30C outside. This shuts down the Victron controller. The Victron was behind the driver seat mounted on the storage unit, so out of direct sun.
The 80 does not act like a fishbowl in my experience. Maybe a difference between the JDM glass spec and NA spec glass...not sure.
I've the standard aluminum framed panels on the roof of both, so not part the equation or this discussion.
gb
I've a Victron 100/15 in 80 and it has never shut down.
The BJ74 is a fishbowl in the sun when locked and windows up. Factory glass tint in the BJ74 does little to block the rays. Having all windows done with a modern tint would likely help considerably. I've a temp gauge in a power port on the dash and have seen 60C with the vehicle parked in the sun, when it's in the 20/30C outside. This shuts down the Victron controller. The Victron was behind the driver seat mounted on the storage unit, so out of direct sun.
The 80 does not act like a fishbowl in my experience. Maybe a difference between the JDM glass spec and NA spec glass...not sure.
I've the standard aluminum framed panels on the roof of both, so not part the equation or this discussion.
gb
I have read that some Victrons will derate if the controller becomes too hot. Coincidentally -or not-, 60C was mentioned as the limit. Don't know if that is internal or the heat sink temp. But practically speaking, I would think that that is quite unlikely to be reached outside of very unusual situations, however, those units are pretty efficient. (And 60C ambience is very high, I don't think that a human could survive more than a few minutes at 60C.)
And I don't think that "derating" means shutting down completely either, my impression is that the unit will just limit the output to not exceed a given temperature (but not sure TBH).
And I don't think that "derating" means shutting down completely either, my impression is that the unit will just limit the output to not exceed a given temperature (but not sure TBH).
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- #18
Solved, Lensun 100w semi-flexible panel s*** the bed, zero output, funny, the 15w rigid panel, 16 years old was still working but only partly shaded, in full sun it zeros out, any suggestions on reliable panels to mount on an aluminum roof skin ? Apparently when mounted with the four corner eyelets and going down the freeway the panel flutters/vibrates and that killed it. Still deciding on an air gap material and now a new fastening method, lesson learned.
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Will do, I popped the cap off the junction box, internals were sealed, cap was removable, I did not break anything, wires did not appear easy to access, I will poke around and see if I can get to the circuit where it transitions from board curcuit to wire. and test there, good idea.
