The degradation is nothing like as extreme as suggested, and I repeat that 52C is not that hot for a panel. People get confused because it's too hot to touch, but that's not the same thing at all. In the old days data centres were set to 20C until we realised that 38C was fine for the servers and acceptable for humans.
The temperature coefficient of solar panel typically ranges from 0.25 to 0.5 % per degree centigrade and is usually expressed from 25°C so at 52°C you could expect up to 10% loss of output. It's physics you see or perhaps you don't.
Do you have any 50w Renogy panels? You are adamant that there is nothing wrong with my four but you can offer an explanation as to why. I am a qualified engineer. I spent my whole career in mechanical and electrical engineering. I know how to test a solar panel performance. The panels are crap. There is no other viable explanation. Your larger panels may well perform there socks off but the 50w panels don't.
Geem is one of the more knowledgeable posters on here.
I am not convinced. Rigid solar panels have a significantly longer life in my experience.
This degrades the output, but thermal cycling is also one of the major factors that causes micro cracks. Unfortunately, micro cracks also trigger hot spots within the panel causing further problems. Solar panels have a higher output and will last longer if you can keep them at a reasonable temperature. See this paper:
I will be fitting new felixible solar panels to replace the Renogy 50w one. It will be interesting to see how new ones perform. If you have any recommendations for high quality flexi panels I would be interested
Renogy ones ARE high quality. Whatever panels you buy, if you're unwilling to put the work in to get them to perform then you will view them as poor. Same as anything in life.
Haha, you are kidding! Renogy are NOT high quality! They have a rock bottom reputation in the USA. I know Trident on here will have a different opinion but that is not shared by the US sailing community.
Good to hear you experience of Renogy.In the US Renogy have a lot of issues over customer service and that gets them a bad rep - Will Prowse who you have quoted though loves the quality on many of their products and so far in 4 years I have not had any issues with perhaps 150 panels, 50 plus MPPT and dozens of inverters etc and of course maybe 200 LIfePo4 batteries. I also use their stuff day in day out myself on my boat and have had zero issues - not one - better than advertised power from the panels, no problems with the batteries or MPPT or DCDC (though still only used for many an hour in 3 years so ...) I have had no customer complaints about any products I fitted and only one query about one I supplied but did not fit.
I also have Fogstar and Victron accounts and have more issues with Victron than anything else - but I will say that is never so far to do with quality and more often to do with complex set up on some products that still need dedicated hardware to program and so on - plus an hour on the phone trying to get a log in code from Denmark with no reply so having to google and some one online said try **** which turned out to be right
Currently I can see no better panels than Renogy - the Maxeon are great for big cats but too big for most, the Victron are over priced and last year's tech so not as efficient as Renogy or Maxeon and others have supply issues etc . I will from now on be building all my own battery packs with EVE cells and JK BMS as the pricing has made them cheaper and better now than other choices (though as I said no issues at all with Renogy batteries) but MPPT will normally be Renogy and sometimes Victron (I think the Renogy MPPT are better) .
If you want when you get back to the UK post me the Renogy panels (I'll pay the shipping) and I'll test them for you and see what I find and post here . If they are crap I'll be happy to send them back to the very helpful UK trade team (well its one guy but he goes out of his way to help) and expedite replacement
I'm not going to remotely argue that you are wrong in your assessment as I respect your experience but our experiences of the same product vary hugely and I'm interested to discover why.
The only thing I would do differently from you is test each individually at 12v to check each against the other and see if one is weak / damaged and check cables and connectors too - I don't say you're doing anything wrong but if they are "crap" then to talk to Renogy about it I'd always prefer to be able to say "i've tested these and there is a problem" so they can't argue.
I filed a request with Renogy today. There is a strange anomaly with the SKU number. Mine are RNG-50DB-H-US. On the automated process, this SKU number didn't come up.
It does help to go to 100% periodically to trigger cell balancing - once a week or every other week.It never hurts to have high acceptance rate. But yes it's even more beneficial if you're generator or alternator charging.
As originally installed, we would peak at about 0.2C charge rate from solar. We've since doubled the battery capacity so now it's more like 0.1C.
What kind of current do lead acids accept once they come off bulk?
I forgot to mention one other benefit of lithium- they don't care a jot if they don't reach 100%. No sulphation to worry about
In principle yes, but if you have a half decent BMS (yet another advantage of going DIY), you can set the balance voltage to whatever you want. Mine is set at 3.4v, so I don't need to push the cells up to the 100% point.
I have framed panels that were not expensive yet they outperform their rating on a regular basis. At the same time, I have these Renogy panels that have woeful performance. I don't need your blessing or your suggestions that I am testing them incorrectly to know they are faulty. They are faulty. They have never reached anywhere near their rated output. Some of that can be explained by the higher panel surface temperature of flexible panels mounted on a surface as opposed to framed panels with only air underneath them. However, the truly terrible output of my 4 Renogy panels cannot be put down to temperature difference alone.
Totally agree. EFTP panels don't deamination so readily as the older PET panels. Delamination usually starts at the copper grommets since they corroded. The adhesive silicoln in the
I am not saying yours aren't faulty just a general comment that the rated output on new panels is quite reliable. I really hope you are able to make contact with Renogy and get them replaced. Thanks for pointing out the terrible customer service with Renogy - useful for others the hear.
The victron mppt regulator provided voltage amps, watts and data and logs it all for 30 days. My Fluke meter independently tested each panel. These results were sent to Renogy, as requested in June. They were in line with my tests I did when the panels were brand new. They have never performed anything like they are rated to do. I dont have one faulty panel I have four panels that all have similar poor output. There is something seriously wrong with these panels. As a mechanical and electric engineer and capable of testing panels and determining if they are performing. They do not perform.
