Marks on my solar panel, are they a problem?

[peterc10]

Went up the ladder to clean the Sahara desert off my 6 years old solar panels today and discovered these odd marks on one of the panels. They extend to 3 or 4 of the squares. Are they a problem or is it just a natural phenomenon?

Do I need a new panel?

 

[TinaLes]

Are the marks under the glass?
If so it looks like you have condensation problems, this will probably affect the output from the panels, however if you can check with an amp meter/volt meter, and its within your tolerance/needs for batteries to get back up to strength, then just put up with them for a while longer. It really is whether they are doing the job for you that counts, if you have a back up B2B charger when on a run, then even better.
Good luck, hopefully its just cosmetic.
LES

 

[peterc10]

It is under the glass. It is a 150W panel and I also have a 100W one and they are wired together. It is very difficult to know exactly what power you should be getting at this time of year from the 250W of solar. As long as I am not using the motorhome they will be OK because I am plugged into the mains. But we will be using it in Europe in the very near future and spending most of the time off grid. Experience tells me that we can easily cope with the two panels. But I doubt we would if the larger panel is duff.

 

[SIFTA SAM]

It is under the glass. It is a 150W panel and I also have a 100W one and they are wired together. It is very difficult to know exactly what power you should be getting at this time of year from the 250W of solar. As long as I am not using the motorhome they will be OK because I am plugged into the mains. But we will be using it in Europe in the very near future and spending most of the time off grid. Experience tells me that we can easily cope with the two panels. But I doubt we would if the larger panel is duff.

Were both panels obtained from the same supplier?

 

[peterc10]

Were both panels obtained from the same supplier?

I don't know. They were fitted by the dealer as part of the deal to buy the motorhome. They have been fine up to now and may well still be fine. But I don't want to find out that they are not fine in the middle of rural France/Spain/Portugal.

I am really hoping that somebody will recognise what they are and if they will cause any problems.

Lenny HB
Raul
eddievanbitz

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[eddie]

It’s called Snail Trail, and has a number of possible causes, and the jury is out regarding if it impacts on performance or not

 

[SIFTA SAM]

For info : - https://www.winaico.com/blog/common-solar-panel-defects/

 

[Lenny HB]

Not seen it before but looks a bit of corrosion caused by damp getting in, I think you will just have to monitor it & see if it gets any worse effect on performance is a difficult to measure as the brightness of the sun is constantly varying.

On a nice bright day you could discharge your batteries a bit then you could unplug and measure the output from each. Best if two of you do it as one can look at your BMV while the other does the swapping to get the best result. Although two different size panels a bit of simple maths will sort that.

 

[Raul]

That’s a classic example of micro cracks. They open in hot weather and brown the contacts. Yes the panel will still work, but at reduced.capacity, due to the resistance induced by the brown points. Snail trail is a bit more subtle, but not far of it. It is possible that was less obvious a year before. I have a couple like that, not worried yet, until the burning of lattice gets to big to transfer any current.

 

[Raymond Bonello]

Went up the ladder to clean the Sahara desert off my 6 years old solar panels today and discovered these odd marks on one of the panels. They extend to 3 or 4 of the squares. Are they a problem or is it just a natural phenomenon?

View attachment 596771

Do I need a new panel?

I fear you have a disc

Went up the ladder to clean the Sahara desert off my 6 years old solar panels today and discovered these odd marks on one of the panels. They extend to 3 or 4 of the squares. Are they a problem or is it just a natural phenomenon?

View attachment 596771

Do I need a new panel?

It looks like you have a disconnection in the internal wireing of the panel. Visually it is not enough to conclude but have to test the system with a meggar or volt meter. Speak to the people you bought the panels from to give you an idea or an estimate if that is the case. Regards

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[RogerIvy]

As Eddie stated it's called a Snail Trail.
The industry has pretty much moved on from "Don't know if it degrades performance" to "It degrades performance but by how much we don't know". General thinking is that moderate damage drops 20-30% and of course eventually a panel produces nothing if severe damage and in the right places. Some panels even have a hole "burnt through" if it's really bad.
The challenge is how to define minor, moderate and severe damage. No real definition. I guess if you've recorded output for given sunlight conditions you would be able to determine performance degradation ... but who does that?

 

[gwyntaxi]

It is under the glass. It is a 150W panel and I also have a 100W one and they are wired together. It is very difficult to know exactly what power you should be getting at this time of year from the 250W of solar. As long as I am not using the motorhome they will be OK because I am plugged into the mains. But we will be using it in Europe in the very near future and spending most of the time off grid. Experience tells me that we can easily cope with the two panels. But I doubt we would if the larger panel is duff.

I have got 2x90w of solar panels on the roof and I’m a little puzzled as to why you need to be plugged into the mains, if I don’t use my van all winter the panels keep the two Leisure batteries and vehicle battery fully charged without any need for ehu at all, if this is not the case with you, the panels need checking out. Just sayin.

 

[GirlyVanGirly]

I have got 2x90w of solar panels on the roof and I’m a little puzzled as to why you need to be plugged into the mains, if I don’t use my van all winter the panels keep the two Leisure batteries and vehicle battery fully charged without any need for ehu at all, if this is not the case with you, the panels need checking out. Just sayin.

I agree, I only have 160w and regularly check the battery, even after a cloudy spell it's ok. We only put it on EHU for the night before we go away because we load up the fridge, just to be on the safe side.

 

[DuxDeluxe]

I have got 2x90w of solar panels on the roof and I’m a little puzzled as to why you need to be plugged into the mains, if I don’t use my van all winter the panels keep the two Leisure batteries and vehicle battery fully charged without any need for ehu at all, if this is not the case with you, the panels need checking out. Just sayin.

Same here, even though (a) the panels are 8 years old and (b) oop Norf the sun is very low in the winter and the van only gets sunlight for a couple of hours even on a good day due to shading from the bungalow. It has never dropped below 90% on the Victron smart shunt readout Even after a week of appalling weather. EHU goes on the day before a trip so the fridge is down to temp without using gas

 

[peterc10]

I have got 2x90w of solar panels on the roof and I’m a little puzzled as to why you need to be plugged into the mains, if I don’t use my van all winter the panels keep the two Leisure batteries and vehicle battery fully charged without any need for ehu at all, if this is not the case with you, the panels need checking out. Just sayin.

I don't need to, I choose to. I park 6ft from an outside socket so why not.

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