Ordered a FLIR phone attachment mostly for fun (sure, sure I had some excuse about checking my insulation ) Anyway, took some photos of my panels in the height of the day. I was surprised to see them actually cooler than my roof surface. Figured they would be hotter. Here is my East facing array. Dunno why I have that weird differential between the cells in the middle. Here is my South array: And here are my inverters. The Powerwalls weren't charging or discharging when I took the pics, so no interesting images of them.
IR behaves a little differently than visible light. You might be seeing a reflection of the sky more than the temperature of the panels... kinda like you can easily see your own reflection in a window with IR and IR cannot see through a window. My favorite science experiment with IR is it's ability to pass through plastic. Have someone hold up a black plastic trash bag. To IR it's almost completely transparent. Highlights how global warming works. CO2 is transparent to visible light but opaque to IR. SCIENCE!
True - so maybe they are hotter than my roof and I am just seeing the glass reflection? No clouds in the sky today (and luckily, no smoke either, ugh) Apparently diagnosing solar panel problems using thermography is an actual thing, which is pretty cool actually. http://www.murcal.com/pdf%20folder/15.testo_thermography_guide.pdf . They even make drones for it. Makes me wonder about that sharp temperature differential between panels on the east roof. (I have actually been arguing with Tesla that something is not right with my install on the east roof, so I am sending them the first image to see if they will at least send a tech out to inspect it, which they have so far refused to do.)
Do you have performance data for the East roof? Discovering issues with solar modules using thermography is a thing but only under fairly specific conditions. Ironically a clear day is unlikely to yield results since ~99% of the thermal energy is likely to be from the sun and not a fault. I was able to see a cell in a module that had become a load due to shading on a cold cloudy day. This effect is barely visible on a sunny day.
Excellent, I’ve got one of these myself (birthday present for myself this year... ), will try it out on my panels if TE ever gets our utility approval done.
Good info I may have to try it on a cloudy day (in a few months when we get one, LOL) Not a ton of data, and I only get what I can see on the Solar City website. I have Delta string inverters so no panel data like SolarEdge. System has only been active for 2 full months. Here is what I am seeing so far monthly vs my PVWatts estimate runs. Notice the East array is underperforming the estimates and the South is over-performing. That is what makes me think I have a problem of some sort on the east array.
Hopefully. My roof was noted on the Tesla design as a 6/12 pitch both sides, which should be 26.6 according to PVWatts. I used 90 for the East facing roof and 180 for the South roof according to the info in the PVWatts help. I set the panels as fixed, roof mounted and left them as Standard, even though they could probably be classified as Premium (Panasonic 315W panels). I left the losses as the default.
Update: Tesla finally agreed to escalate my case and sent a Tech out. He figured out the wiring to those 6 panels was bad causing some problem to the RSD. Already seeing improved performance today. Customer service is great if you can get past the front line phone support people. Before that it is terrible.
I wonder how the wiring could be bad when it seems to be just snap them together. You confirmed with your thermal camera?
Haven’t had a chance to look on the thermal camera yet. I am already seeing results in my data though. Tesla was fixing it the afternoon of the 24th, so the 25th was my first full day after the fix. Frankly, I have had so many problems with my install, I am not surprised at all. From taking over 2 months to click a button to submit my PTO to installing the wrong panels on my house and having to come back a month later and completely reinstall the right panels, absolutely nothing shocks me at this point.
Good detective work. That FLIR image should have been a dead giveaway that something was wrong. Glad they fixed it.