Has anyone ever had a solar panel expire? I have an array of Enersol 300W panels and one string was giving intermittent issues (not charging), so I isolated it to one panel that seems to be producing half voltage. The open circuit voltage is <30V. I measured just now (although the sun was low) and it was 23V. 

Is there anything that I can test and fix, or is this just a dud and needs replacing?

Specs:

Electric performance at STC *
Maximum Power 300 Wp
Power Tolerance 0/+5 Wp
Module efficiency 15.4%
Maximum Power Voltage 36.6V
Maximum Power Current 8.20A
Open Circuit Voltage 44.8V
Short Circuit Current 8.69

PS, the other two panels in the string produce 40V at the same time of day.

3 hours ago, DeepBass9 said:

PS, the other two panels in the string produce 40V at the same time of day.

The 1st thing is check the diodes. It might be that one of the 3 sets of diodes are in bypass. They are not expensive once located which one. Check the voltage for each set of 2 columns. This is while the whole panel is in the sun.

I have had a new panel going open circuit and would cause not current flowing in the series string. When it was bypassed just like before I added this 4th panel all was OK. If I did not have graphs to show the voltage and amps when connecting 3 and 4 the seller might have not believed it was possible. Had to wait for a replacement from CoCT and all is still well 3 years on.

Enersol are Tier 2 panels. So one would find that the quality control may not be what a Tier 1 could be. I hope it's just a dud & can be replaced. See if you can warranty claim on it. 

9 hours ago, Scorp007 said:

The 1st thing is check the diodes. It might be that one of the 3 sets of diodes are in bypass. They are not expensive once located which one. Check the voltage for each set of 2 columns. This is while the whole panel is in the sun.

I have had a new panel going open circuit and would cause not current flowing in the series string. When it was bypassed just like before I added this 4th panel all was OK. If I did not have graphs to show the voltage and amps when connecting 3 and 4 the seller might have not believed it was possible. Had to wait for a replacement from CoCT and all is still well 3 years on.

I'll give that a try. The box on the back of the panel is glued on so I am going to have to break that off before I can see inside. Here's a video on how to test : 

I think probably the easiest is to just replace the panel. Its only one panel and they are not too expensive. 

8 hours ago, DeepBass9 said:

I'll give that a try. The box on the back of the panel is glued on so I am going to have to break that off before I can see inside. Here's a video on how to test : 

I think probably the easiest is to just replace the panel. Its only one panel and they are not too expensive. 

Thanks for the reply. Yes I see the new trend is to glue the cover on. 3 years ago they mostly had a cover with screws and a gasket so that the diodes could be attended to.

So I broke open the back of the panel junction boxes and tested the diodes. I had to saw open the box with a hacksaw, and it was full of some spongy gloop which had to be scraped away.

I tested the diodes with the multimeter diode setting and got 1 , 1 and blank in the one direction, and then 134, 128 and -599 in the other direction. I'm not sure what these numbers mean, but I guess it means the 3rd diode's smoke has escaped.

I don't see any identifying numbers or marks on the diodes, maybe it is on the back of the diode.

Now to buy a soldering iron and get the diodes off and try and find replacements.

 

17 minutes ago, DeepBass9 said:

So I broke open the back of the panel junction boxes and tested the diodes. I had to saw open the box with a hacksaw, and it was full of some spongy gloop which had to be scraped away.

I tested the diodes with the multimeter diode setting and got 1 , 1 and blank in the one direction, and then 134, 128 and -599 in the other direction. I'm not sure what these numbers mean, but I guess it means the 3rd diode's smoke has escaped.

I don't see any identifying numbers or marks on the diodes, maybe it is on the back of the diode.

Now to buy a soldering iron and get the diodes off and try and find replacements.

 

10sq050  pec  4159 will do the trick. GT Electronics had the in stock. They are in Boksburg

Thanks! I'll see if I can find some on the West Rand or Rustenburg.

Is this the right thing? : https://www.communica.co.za/pages/search-results-page?q=10sq050

Yes it is good for 50v 10A. Should be OK

 

I replaced all 3 diodes, but still no joy. What I can see now though is that one of the 3 cell arrays is completely dead, and producing zero volts even in bright sunlight. I believe the problem is therefore a defect on the panel, either in manufacturing, or a microcrack from a hailstone or something like that.

So it looks like I will have to replace the panel.  I will keep the old panel though, and just rewire it to be a 200W 24V panel, which I'm sure I'll find a use for somewhere else. I have a cottage that runs on an ancient 50W panel to drive some 12V LED lights which I'm sure could make better use of a 200W panel.