Interesting Observation...

[danesol]

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.

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 ??

 

[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

 

[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.

 

[FB.]

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

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.

 

[FB.]

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

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

 

[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.

 

[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.

 

[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.