ChrisCM Posted July 28, 2019 Share Posted July 28, 2019 I recently posted regarding my solar controller, an Amperor unit which I suspected of being faulty. I was generating no solar power once the outside air temperature went above about 30 degrees. I have now substituted this controller with a victron unit, when I connected this I got no output or indication of panel voltage from the roof mounted 70w panel. So I then connected a 60w folding panel to the Victron and placed it in the window of our van, it immediately gave about 20w not surprising as the panel was partially folded. However after a few minutes in the window the panel got rather hot from the sun and output dropped to zero but the voltage held up. Is my experience normal, do roof mounted solar panels normally shut down when subjected to high temperatures? Link to comment Share on other sites More sharing options...
spirou Posted July 28, 2019 Share Posted July 28, 2019 It is normal to have reduced output with higher panel temperature. That's the reason why you want an air gap under the panel and why panel output can be greater than rated under very low temperatures, but this would be a few percent + or -, not zero output. At least regarding victron regulator, is it possible it detected a full battery and went into float phase? In our case, when van isn't used, it will drop to 0A, 13,xV quite soon in the morning. The bulk & absorbtion phases can last less than an hour combined and would probably be even shorter if the sun was be higher at start. Link to comment Share on other sites More sharing options...
Paul- Posted July 28, 2019 Share Posted July 28, 2019 Controllers also like it cool and not stuck into a top airless cupboard, somewhere lowdown with ventilation is best (near to a gas drop vent) and preferable onto a heatsink. Link to comment Share on other sites More sharing options...
ChrisCM Posted July 28, 2019 Author Share Posted July 28, 2019 Yes, I thought this would be the case, but what seems to be happening is that there is some output in the morning then once it heats up zero. The batteries are not fully charged, running at about 12.6 -12.7v at about 75-80% capacity. I’m not too happy with the solar installation done by a “professional” for the previous owner. The original fitted solar panel was an 80w flexible type bonded to the roof, a replacement 70w panel has just been stuck on top of the old one by the “professional” so I think I’m going to have to strip the lot off and start again! Link to comment Share on other sites More sharing options...
ChrisCM Posted July 28, 2019 Author Share Posted July 28, 2019 Paul- - 2019-07-28 5:26 PM Controllers also like it cool and not stuck into a top airless cupboard, somewhere lowdown with ventilation is best (near to a gas drop vent) and preferable onto a heatsink. Controllers are both low down under a bed box with room for air circulation. I’m coming to the conclusion that the roof panel is u/s. Link to comment Share on other sites More sharing options...
colin Posted July 28, 2019 Share Posted July 28, 2019 Are you sure the batteries are OK? Link to comment Share on other sites More sharing options...
ChrisCM Posted July 29, 2019 Author Share Posted July 29, 2019 colin - 2019-07-28 6:55 PM Are you sure the batteries are OK? Yes, I hope!, new about 4 months ago. Link to comment Share on other sites More sharing options...
Paul- Posted July 29, 2019 Share Posted July 29, 2019 I'd check all the connections again starting at the battery and up to the panel, could be a connection becoming loose and expanding or wires seteling down and becoming les than a tight fit. Quick fit clamps are usually the culprit. Link to comment Share on other sites More sharing options...
mikefitz Posted July 29, 2019 Share Posted July 29, 2019 The power from a solar panel will be less at higher temperatures, typically 10 to 15 %. (The loss is about 0.5%per degree C above 25 degree C). In this case I suspect failed and failing solar panels. The interconnections in flexible solar panels are not very reliable in many of the panels now on the market. Mike Link to comment Share on other sites More sharing options...
colin Posted July 29, 2019 Share Posted July 29, 2019 ChrisCM - 2019-07-29 6:35 AM colin - 2019-07-28 6:55 PM Are you sure the batteries are OK? Yes, I hope!, new about 4 months ago. When it's showing as no output from panels put a load on to double check. Link to comment Share on other sites More sharing options...
ChrisCM Posted July 29, 2019 Author Share Posted July 29, 2019 I’m coming to the conclusion that the panel has failed, both controllers are showing the same, ok for a couple of hours, giving up to 20w with the sun a few degrees above the horizon, then as it rises and things start to heat up it drops to zero. It comes back to life in the evening for an hour or so before the sun sets. checked them with a volt meter and the “hot” reading is zero as reported by the controllers. Luckily I’m doing a few hours a day driving so the batteries are taking a charge from the alternator. I’m still under warranty so I’ll see what the dealer says when I return to the UK at the end of next month, hopefully we can can come to some arrangement to have rigid panels fitted to replace the failed one. Link to comment Share on other sites More sharing options...
colin Posted July 29, 2019 Share Posted July 29, 2019 As you have posted that the output from a folding panel also dropped to zero I'm not sure how you can pinpoint it to roof mounted panel. Link to comment Share on other sites More sharing options...
ChrisCM Posted July 30, 2019 Author Share Posted July 30, 2019 colin - 2019-07-29 10:18 PM As you have posted that the output from a folding panel also dropped to zero I'm not sure how you can pinpoint it to roof mounted panel. I was really just using the folding panel to check the controllers. It’s a concertina type with 8 panels, I just partially unfolded it and placed it in a window of the van where it did produce an output, nowhere it’s rated output. It’s specified to 60 degrees C. However though the current flow dropped to zero there was still a nominal voltage of between 17-18v whereas the roof panel drops to zero current and volts. As I write this the sun is low and it’s relatively cool, 17 degrees C, in the Pyrenees the roof panel is producing 22w Link to comment Share on other sites More sharing options...
ChrisCM Posted July 30, 2019 Author Share Posted July 30, 2019 Update, the roof panel stopped working about ½ an hour after I last posted, I rigged the folding panel in a far from perfect location hanging off our sliding door and it’s working perfectly, given its location, consistently producing about 20w. Thing about the roof panel, it wasn’t that hot, <20 degrees, when it stopped working so the problem may be more to do with the actual panel components failing as they are producing power rather than being caused by excess ambient heat, could be dry joint or a failing blocking diode whichever way it’s u/s! Link to comment Share on other sites More sharing options...
Paul- Posted July 30, 2019 Share Posted July 30, 2019 Flexible panels do have a short lifespan and especially if they haven't stuck it properly, so I can see why they fitted another panel, If the new panel is also a stick on type and stuck over the old panel it will also have a short lifespan and will have problems from overheating. Link to comment Share on other sites More sharing options...
ChrisCM Posted July 30, 2019 Author Share Posted July 30, 2019 Agreed, one way or another I’m going to get the old panels off and replace them with quality rigid replacements, any recommendations anybody? Been looking at the victron mono type, I think I’d have more confidence in them than some cheap no brand! Link to comment Share on other sites More sharing options...
mikefitz Posted July 30, 2019 Share Posted July 30, 2019 'Been looking at the victron mono type' Have a look at, https://www.onboardenergydirect.co.uk/shop/Victron-Solar-Panels.html the company is a main Victron supplier. You could try this promotion code JONOPROMO, for a 15% discount. I would fit the largest panel you have space for, if you are using a Victron controller it will safely accept a panel power greater then the controller rating. ( it just limits the output to its own rating). Mike Link to comment Share on other sites More sharing options...
ChrisCM Posted July 31, 2019 Author Share Posted July 31, 2019 Many thanks Mike, I’ll get this sorted upon my return to the UK at the end of August (all this lovely sunlight going to waste!) Chris Link to comment Share on other sites More sharing options...
ChrisCM Posted September 3, 2019 Author Share Posted September 3, 2019 Hi Guys, Just an update, have ordered two 100w panels from OnBoard Energy, with a 15% saving using the code supplied by Mikefitz so many thanks Mike! Now the fun of fitting them! Link to comment Share on other sites More sharing options...
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