One cell running hotter, is it shorted? (Thornova TS-BGT54(500W))

[timbit123]

If you look at the first solar panel, it have only one cell that look like it is running hotter since snow is melting only there.
Also, it is only 10F outside right now, it is cold.

Also during sunny day, I get around 1500watt max on 4000watt total, could it be because the bottom are a bit under the snow and I only get half of the solar panel?

Don't mind the installation, I have a ground mount but I cannot install it until winter is over

 

[sunshine_eggo]

If you look at the first solar panel, it have only one cell that look like it is running hotter since snow is melting only there.
Also, it is only 10F outside right now, it is cold.

Also during sunny day, I get around 1500watt max on 4000watt total, could it be because the bottom are a bit under the snow and I only get half of the solar panel?

Don't mind the installation, I have a ground mount but I cannot install it until winter is over

I can't imagine a hot cell can be a factor in 10°F weather when there's no sun.

I'm shocked you get 1500W out of 4000W with snow on the bottom of the panels. Generally speaking, the way panels work means that when you shade a single row of cells on a panel in portrait orientation, you can kill all of the panel's output. The only way that wouldn't surprise me is if these are bifacials, and they are getting exceptional sun from the backside.

Also, since we don't know your MPPT specs or battery voltage, we can't determine if you're limited by your charging hardware.

 

[timbit123]

it is weird that at 10F the snow only melt on one specific cell only.
I think those panels have a bypass diode to split top / bottom so I'm not losing everything, but I'm not sure on that.

Inverter is SRNE HESP 12kw and I during 1500watt it was still half of my home usage so it was not limited by power usage

 

[sunshine_eggo]

it is weird that at 10F the snow only melt on one specific cell only.
I think those panels have a bypass diode to split top / bottom so I'm not losing everything, but I'm not sure on that.

Ah... I didn't realize they were half cut cells, so the junction box and wires are in the middle of the panel instead of one end? Now that I count the cells, it looks like 108 total, which would be 54S2P.

If so, 1500W sounds about right since you've lost 50% of the panel with snow covering a whole row of cells.

Inverter is SRNE HESP 12kw and I during 1500watt it was still half of my home usage so it was not limited by power usage

So, 48V system with a lot of MPPT capability.

Often folks will hang multi-thousands of watts off a MPPT and not realize that they MPPT can't handle it because they've interpreted the current rating as an INPUT limit rather than an output limit.

 

[sunsurfer]

it is weird that at 10F the snow only melt on one specific cell only.
I think those panels have a bypass diode to split top / bottom so I'm not losing everything, but I'm not sure on that.

Its not a sure thing. Everyone thinks bypass is the end all be all but its only a patch job and there is a threshold for bypass. You have to have enough forward bias. And the bypass diodes have limits. It's why they fail.

I've tried to tell people on here about the issues with going high power strings but everyone just has normalcy bias. You all are just a bunch of normalcy diodes.

 

[timbit123]

this is the datasheet of the panel, yes the connections are in the middle

If I take the NOCT value (382watt) / 2 = 191watt then *8 panels = get 1528watt and I get around 1500-1580watt

Its not a sure thing. Everyone thinks bypass is the end all be all but its only a patch job and there is a threshold for bypass. You have to have enough forward bias. And the bypass diodes have limits. It's why they fail.

I've tried to tell people on here about the issues with going high power strings but everyone just has normalcy bias. You all are just a bunch of normalcy diodes.

I only have 8 panels, it is not a huge setup. I just wanted to learn on that.

 

[sunshine_eggo]

this is the datasheet of the panel, yes the connections are in the middle

If I take the NOCT value (382watt) / 2 = 191watt then *8 panels = get 1528watt and I get around 1500-1580watt

NOCT isn't really applicable to winter conditions. NOCT is intended to reflect what happens when the solar panel heats from the sun as that heat diminishes output in the form of reduced voltage. NOCT/NMOT is basically representative of 80% STC sunny conditions.

The snow is literally killing the output of the bottom half of the panel. You now have a 2000W array. 1500W out of a 2000W array in Winter in Canada is darn good. If you want more, scrape your panels clean and double your output.

 

[timbit123]

NOCT isn't really applicable to winter conditions. NOCT is intended to reflect what happens when the solar panel heats from the sun as that heat diminishes output in the form of reduced voltage. NOCT/NMOT is basically representative of 80% STC sunny conditions.

The snow is literally killing the output of the bottom half of the panel. You now have a 2000W array. 1500W out of a 2000W array in Winter in Canada is darn good. If you want more, scrape your panels clean and double your output.

yeah I'm a bit scared to damage the panel trying to remove the snow / ice

 

[sunsurfer]

yeah I'm a bit scared to damage the panel trying to remove the snow / ice

Pee on them, the salts will melt that ice right off. I don't recommend it for washer fluid FYI

 

[SolarReaper]

Yeah, that's an odd thing happening there. I take it most of the snow is staying frozen and just blowing off the cold surface of the panels in most places, but that one cell is warmer so the snow is melting, and sticking to the panel? Can you get a closer picture? How old are the panels? Still in warranty?
Either way, I'd make some effort to clear the snow from the bottoms of the panels, a soft brush should be OK on the glass, then clear down to ground for a foot or so in front to allow light to get at the bottoms.

 

[timbit123]

Yeah, that's an odd thing happening there. I take it most of the snow is staying frozen and just blowing off the cold surface of the panels in most places, but that one cell is warmer so the snow is melting, and sticking to the panel? Can you get a closer picture? How old are the panels? Still in warranty?
Either way, I'd make some effort to clear the snow from the bottoms of the panels, a soft brush should be OK on the glass, then clear down to ground for a foot or so in front to allow light to get at the bottoms.

I ordered a solar panel tester just to make sure it generate like the others. Those panels are brand new 5-6months max. yeah it was windy and cold this day and know was sticking only on that specific cell because it was probably hotter than the others.
We had a lot of snow the past days, it will be hard to clean them up completely.

 

[timbit123]

I don't know if someone already tried to use heating cable or some call them heating tape to melt the snow / ice on solar panels