Snow on panels

Equaliser123

Panels (Sharp 235w) are just about clear. Bottom 20% still has a snow covering.

Interestingly, not producing anything at all - and haven't done for last 3 days. Not expecting much but would have thought a few watts would be flowing.

Any ideas why? Does the whole of the panel need to be uninhibited? Or could the snow have caused some damage? Or does the inverter need a bit of a restart?

WestonDave

Not sure why it works like that but mine weren't giving anything yesterday despite being mostly clear, and only started up around lunchtime today - probably around the time they cleared a bit more. Not sure at present what is on the back ones - the side ones are fairly clear.

Equaliser123

WestonDave wrote: »

Not sure why it works like that but mine weren't giving anything yesterday despite being mostly clear, and only started up around lunchtime today - probably around the time they cleared a bit more. Not sure at present what is on the back ones - the side ones are fairly clear.

That's interesting. It's actually reasonably bright now and only a bit of snow on them but still producing nothing.

EricMears

Equaliser123 wrote: »

Panels (Sharp 235w) are just about clear. Bottom 20% still has a snow covering.

Interestingly, not producing anything at all - and haven't done for last 3 days. Not expecting much but would have thought a few watts would be flowing.

Any ideas why? Does the whole of the panel need to be uninhibited? Or could the snow have caused some damage? Or does the inverter need a bit of a restart?

Really all depends on how the panels are connected. If they're in a single string just one panel at zero output will effectively swirch them all off. If there's more than one string then you're in with a chance of one string working even though other isn't.

WestonDave

That makes sense Eric - mine SW panels were clearing but the corner one was still covered until lunchtime today so that's when they started working. The SE panels are still pretty heavily covered so won't be getting anything from them for a while

Equaliser123

Difference with mine is that the (single string) are spread 14 across. Only the bottom 10% is of the array is snow-covered but they are not producing at all.

rogerblack

Equaliser123 wrote: »

Difference with mine is that the (single string) are spread 14 across. Only the bottom 10% is of the array is snow-covered but they are not producing at all.

Solar panels are almost invariably internally single string.

Many (all?) have several internal diodes so that the solar cells cannot be damaged by having power forced through them when shaded.

Crucially - depending on the organisation - this means that if one cell is shaded, it knocks out not only the output from that cell, but up to 10 or so others.
If it so happens that the groups of cells are arranged vertically - and the bottom cell is shaded - this will knock out every group of cells in that panel - and if all panels are similarly oriented...

You could probably fix this by removing the panels, and re-fitting them at 90 degrees.
Then you would likely find the power only down by 15%.

EricMears

Equaliser123 wrote: »

Difference with mine is that the (single string) are spread 14 across. Only the bottom 10% is of the array is snow-covered but they are not producing at all.

Perhaps one of the real experts will confirm but I suspect that each 'single panel' is actually an array of 40 or so smaller ones wired up in series so a blob of snow in bottom corner of one panel could be enough to switch off the whole of that panel plus any other (large) panels in the same string.

[Roger's post appeared whilst I was still composing. He appears to have said much the same]

I've had another zero day. SPs are in a 4 x 4 array with top 8 on one string and bottom 8 on another. Top 8 cleared (briefly !) earlier in week but the thin film of snow that followed shut them down again. I think top 4 may have cleared today but since they're in same string as second row they still produced nothing.

Only (slight) consolation is that even if they were all clear I'd only earn a pound or two per day so don't feel too bad about not bothering to climb up ladder to clean them off. If we have more snow in June I'll perhaps feel differently

jamesstephenson57

These solar panels are made of a slippery glass. When a corner of the panel is exposed, it heats up the rest of the module and snow will easily slide away. In the case of heavy accumulation, this could take more than one day to melt. It is better to wait instead of trying risky methord to get rid of the snow

Fruit_and_Nut_Case

jamesstephenson57 wrote: »

It is better to wait instead of trying risky methord to get rid of the snow

How about if I used a non-risky method. Would it still be better to wait?