OP
Silly Sausage
Unlike this one near me, roof facing due East!
There's another panel out of view behind the small gable!
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Unlike this one near me, roof facing due East!
There's another panel out of view behind the small gable!
Y
W
F
That would mean quite a difference in performance, considering that the two arrays "on paper" are very similar.
When the picture was taken (about 9.45-10am), the inverter for my array (the 15x250W) was outputting at a rate of about 1.8kWh per hour, compared to usually putting out about 2.2kWh per hour in similar sunlight conditions recently when there wasn't snow partially obscuring the panels.
It had been generating at about 0.5kWh per hour when I crawled out of bed around 8.30am this morning (suffering from man-Flu).
With two panels completely covered with snow and with six other panels slightly impaired (let's say equal to one more panel of complete obstruction), that's only 12/15panels (80%) of the area functional, yet the system was generating 1.8/2.2kW (82%) of the output that would have been achieved without snow.
So the loss of output from shaded/snowed-in panels - even considering the strings and the active bypass circuits on the panels - seems to not be nearly as bad an effect on other panels in the same string as many people suggest.
O
Or one house has the thermostat set higher than the other. lol
M
W
D
D
I have noticed myself that my Sanyo HITs clear snow very well and very quickly and have never really have any snow on them when running even at low output............
EDIT:- Also when water runs off them it seems to act exactly the same as on a well WAXED car
OP, Can we safety assume the house on the right is even switched on and working, hence why I asked earlier comparison of figs at this exact point would be so interesting ??
D
M
F
Yes, I will definitely speak to the neighbour to find out what is fitted and report back here.
Their system is fully operational as far as I know - there hasn't been anyone come back since the panels were fitted a few months ago. I would be very likely to know if someone had been back as I work from home nowadays and we have a narrow, shared driveway.
I was reluctant to post my system details until the neighbours details were also known, to allow a fair comparison and avoid any prejudice. But to avoid keeping people in suspense.....
The apparently "hydrophobic" system on the left is mine and is as follows:
40 degree roof pitch, facing SouthEast, large open field out the back of the house (no shading from trees/pylons/telephone wires), located in East Anglia.
Kinve 250W mono panels.
Two strings (8+7 panels).
Cables go into loft through the tiles, then across to the side of the loft and down the side of the house, to the inverter which is fitted in a downstairs utility room on the other side (front) of the house (cold North corner; the small amount of extra heat from the inverter's activity doesn't go to waste!).
The two panel strings have separate DC isolators adjacent to the inverter, each feeding into one of its dual MPPT. Total length of DC cables is about 15metres from panels to DC isolator. DC cable is ~5mm outer diameter, ~2mm core.
Inverter is Aurora 3600.
AC isolator is adjacent to inverter and AC cable then runs a couple of metres to the fusebox and electricity meter by the front door.
The system is performing roughy as expected for this time of year, but hasn't yet seen a summer, so the jury is still out on how well it works overall.
F
Panel voltages:
Voc: 37.3
Vmp: 30.1
Isc: 8.78
Imp: 8.31
Array/string voltages:
Voc1: 298
Voc2: 261
Vmp1: 241
Vmp2: 211
Inverter:
Minimum voltage to connect to grid: 200
MPPT voltage operating range: 90 to 580
Full power voltage operating range: 200 to 530
F
L
F
Discuss Interesting Observation... in the Solar PV Forum | Solar Panels Forum area at ElectriciansForums.net
Unlike this one near me, roof facing due East!
There's another panel out of view behind the small gable!
OP
Yanman
Absolutely. I have been trying to figure out how to fit 2 rows of 250w panels on a roof 5.8 x 3.2 to make 3kw. Apparently another company can.
OP
wstevew
Could it be because the one on the left started feed in.
My panels were covered in snow about 10mm this morning and the inverter started feed in. When I left if was producing 150w and looked like it was starting to melt.
My panels were covered in snow about 10mm this morning and the inverter started feed in. When I left if was producing 150w and looked like it was starting to melt.
OP
FB.
That would mean quite a difference in performance, considering that the two arrays "on paper" are very similar.
When the picture was taken (about 9.45-10am), the inverter for my array (the 15x250W) was outputting at a rate of about 1.8kWh per hour, compared to usually putting out about 2.2kWh per hour in similar sunlight conditions recently when there wasn't snow partially obscuring the panels.
It had been generating at about 0.5kWh per hour when I crawled out of bed around 8.30am this morning (suffering from man-Flu).
With two panels completely covered with snow and with six other panels slightly impaired (let's say equal to one more panel of complete obstruction), that's only 12/15panels (80%) of the area functional, yet the system was generating 1.8/2.2kW (82%) of the output that would have been achieved without snow.
So the loss of output from shaded/snowed-in panels - even considering the strings and the active bypass circuits on the panels - seems to not be nearly as bad an effect on other panels in the same string as many people suggest.
Last edited by a moderator:
OP
Octopus
Or one house has the thermostat set higher than the other. lol
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I've seen hot spots on my own Kioto modules, which is strange as they're supposed to have anti-hotspot technology. Anyway the modules showing heated cells clear quicker than the others.
OP
moggy1968
it's not to do with insulation or the temperature in the house as the amount of snow on each roof is about the same. The most likely explanation is that good quality panels come with a hydrophobic coating on. this gives the panels a degree of self cleaning ability which will also reduce the adhesive force between the snow and the panel. Cheap panels either have no coating or an inferior coating. After several years in the optical industry I have seen good quality coatings and bad ones (from the opticians you shouldn't have gone to mostly!) and there is a considerable difference between the two. A good quality coating requires a high level of technical expertise and expensive equipment.
This is one of the things you pay for on a better quality panel
of course I may have my humble pie with ice cream if they turn out to be the same make of panel but thats my view of it.
This is one of the things you pay for on a better quality panel
of course I may have my humble pie with ice cream if they turn out to be the same make of panel but thats my view of it.
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The house on the left could have Suntech 250W hydrophobic coated solar panels, where as the one on the right doesnt.
Either that or Santa polished the panels on the left with Pledge, because he had no chimney to climb down, whereas the house on the right has a tight chimney and he probably ran out of time, trying to squeeze himself down on his alloted delivery slot
Either that or Santa polished the panels on the left with Pledge, because he had no chimney to climb down, whereas the house on the right has a tight chimney and he probably ran out of time, trying to squeeze himself down on his alloted delivery slot
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OP
wstevew
They look like my suntech panels. Mine didn't clear like that, I had a day of zero output. But my roof isn't quite as steep. But the snow did slide off by the next day.
OP
danesol
What would be interesting is knowing the generating figs for both systems at this point in time.... this may also indicate or give you better info for clearer assumption to be made as to what is really going on here and why one system is cleared of snow and the other not, up and above other contributing factors like better loft isolation, heating on higher etc etc
OP
danesol
I have noticed myself that my Sanyo HITs clear snow very well and very quickly and have never really have any snow on them when running even at low output............
EDIT:- Also when water runs off them it seems to act exactly the same as on a well WAXED car
OP, Can we safety assume the house on the right is even switched on and working, hence why I asked earlier comparison of figs at this exact point would be so interesting ??
Last edited by a moderator:
OP
danesol
Also knowing exactly the setup next door would be so helpful, which and how many inverters used, how many strings, panel voltages, startup voltages of inverter(s) etc etc
It seems you could learn alot from this initial observation........ and for good reading here - LOL
It seems you could learn alot from this initial observation........ and for good reading here - LOL
OP
moggy1968
Sanyo, being a good quality panel have a good quality coating. the effect described above of water blobbing up is characteristic of a good hydrophobic coating, where the cohesive forces of the water are greater than the adhesive forces of the surface/water interface.
It's a difficult thing to prove but this would suggest an improved performance on quality panels which doesn't appear in the performance figures as they will self clean better and clear better in the rain. It's these unmeasured aspects of quality panels that mark the difference in the real world.
It's a difficult thing to prove but this would suggest an improved performance on quality panels which doesn't appear in the performance figures as they will self clean better and clear better in the rain. It's these unmeasured aspects of quality panels that mark the difference in the real world.
OP
FB.
Yes, I will definitely speak to the neighbour to find out what is fitted and report back here.
Their system is fully operational as far as I know - there hasn't been anyone come back since the panels were fitted a few months ago. I would be very likely to know if someone had been back as I work from home nowadays and we have a narrow, shared driveway.
I was reluctant to post my system details until the neighbours details were also known, to allow a fair comparison and avoid any prejudice. But to avoid keeping people in suspense.....
The apparently "hydrophobic" system on the left is mine and is as follows:
40 degree roof pitch, facing SouthEast, large open field out the back of the house (no shading from trees/pylons/telephone wires), located in East Anglia.
Kinve 250W mono panels.
Two strings (8+7 panels).
Cables go into loft through the tiles, then across to the side of the loft and down the side of the house, to the inverter which is fitted in a downstairs utility room on the other side (front) of the house (cold North corner; the small amount of extra heat from the inverter's activity doesn't go to waste!).
The two panel strings have separate DC isolators adjacent to the inverter, each feeding into one of its dual MPPT. Total length of DC cables is about 15metres from panels to DC isolator. DC cable is ~5mm outer diameter, ~2mm core.
Inverter is Aurora 3600.
AC isolator is adjacent to inverter and AC cable then runs a couple of metres to the fusebox and electricity meter by the front door.
The system is performing roughy as expected for this time of year, but hasn't yet seen a summer, so the jury is still out on how well it works overall.
Last edited by a moderator:
OP
FB.
Panel voltages:
Voc: 37.3
Vmp: 30.1
Isc: 8.78
Imp: 8.31
Array/string voltages:
Voc1: 298
Voc2: 261
Vmp1: 241
Vmp2: 211
Inverter:
Minimum voltage to connect to grid: 200
MPPT voltage operating range: 90 to 580
Full power voltage operating range: 200 to 530
Last edited by a moderator:
OP
FB.
Picture of my inverter and its associated input/output cables, in the downstairs utility room.
Aurora 3600 inverter with the two grey DC isolators (one for each PV array) to the left, and yellow AC isolator to the right, with cable in trunking going up to the fuse box.
Aurora 3600 inverter with the two grey DC isolators (one for each PV array) to the left, and yellow AC isolator to the right, with cable in trunking going up to the fuse box.
OP
langstroth2
The panels on the left house look to have a slight gap around each panel - the one's on the right are butted up together (I think). Could it be that the gap weakens the grip of the snow, letting each panel shed it's load sooner?
Probably a red hearing.
Probably a red hearing.
OP
FB.
Just been out to look and I think the size of the gap around each panel is just a camera/perspective thing.
Still no chance to speak to the neighbours yet regarding the type of panel fitted.
Still no chance to speak to the neighbours yet regarding the type of panel fitted.
Reply to Interesting Observation... in the Solar PV Forum | Solar Panels Forum area at ElectriciansForums.net
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