Failed PV Panel

Dave_Fowler

Last autumn I noticed that one of the panels on the garage roof looked slightly different from the others; in certain lighting conditions it looked slightly lighter and the silver strips connecting the cells in the module appeared to shine much more.

Checking on the SolarEdge monitoring there was a 5% loss of output compared with the neighbouring panels. This was nothing too unusual as there is a 5% manufacturing difference between the panels and the shading across the roof varies from month to month - but this panel had always been one of the 'middle' performing panels, but had become towards the worst end. Since then, the difference between that panel and those next to it has become more like -15%.

This weekend, with the help of my son I was able to get up to the roof to have a close look at it. The glass is crazed all over - just like the glass in a tempered windscreen when it breaks. Looking directly down on it, you can't really see anything, but at an angle you can see all the fractures in the glass.

There is no sign of any impact; the fragmentation is the same all over the surface. I've no idea what has caused the failure.

Looks like I'm in the market for a new panel. The installers no longer exist.

Dave F

gazapc

There a loads of potential causes but the most likely is a bird dropping a stone. Did it have a 'centre' or possible impact point? Other causes are less likely. Hopefully an easy fix.

Dave_Fowler

gazapc wrote: »

There a loads of potential causes but the most likely is a bird dropping a stone. Did it have a 'centre' or possible impact point? Other causes are less likely. Hopefully an easy fix.

Absolutely no sign of an impact zone. The breakage pattern (minute 0.3" irregularly sided pieces of glass) is consistent both side to side and top to bottom over the entire panel. I'm most surprised to see the crazing is right up to the edges - but perhaps that's the way toughened glass breaks. May be when I get it down off the roof I'll find something.

I need to get looking for a suitable replacement at a reasonable cost. The 250Wp panel is 1650x992x40mm.

legoman62

Dave_Fowler wrote: »

Absolutely no sign of an impact zone. The breakage pattern (minute 0.3" irregularly sided pieces of glass) is consistent both side to side and top to bottom over the entire panel. I'm most surprised to see the crazing is right up to the edges - but perhaps that's the way toughened glass breaks. May be when I get it down off the roof I'll find something.

I need to get looking for a suitable replacement at a reasonable cost. The 250Wp panel is 1650x992x40mm.

https://www.enfsolar.com/pv/panel-datasheet/Polycrystalline/24059

Dave_Fowler

It's the first day with the replacement panel. It was a long saga trying to get a replacement, but finally got a polycrystalline 250W panel to replace the old mono panel (same wattage).

So far, it has proved to be better than the rest. It will be interesting to see how it performs in dull weather - today is bright sun. Perhaps the -0/+5% tolerance of the new panel is the reason; the old panels are -3/+3%.

Although the specification sheet for the panel said it was 40mm deep like the others, on trying to tighten the clamps to fix it to the roof supports, I found it to be a mm or so thinner and the clamps would not tighten. Quite a problem when you're trying to stop the panel sliding down the roof with one hand and tightening the clamp with the other. The temporary solution was to use some 2p coins I happened to have in my pocket as packing pieces. Being a Northerner, there was no way I'd be leaving my money on the roof, so I cut some aluminium pieces from a stock sheet and fitted those.

Having got the old panel to the ground for a close inspection, there was no sign of why the panel had shattered.

Dave F