I took the solar panels down again! Here is what I found

Thank you for all your comment son the solar panel problem videos. The last two and this video here were all recorded within two days so far before I published the first one. No chance to react to any of you comments. I'll do more testing with your suggestions soon.

After some more testing which did not bring any new findings, I decided to take one panel down and connect it back to the PWM controller. Again, I could measure a better current than on the roof.
It seems like, the panels are performing much better in parallel than in series.
So they must be faulty and some cells one the panels may not work correctly any more. Hence the slightly lower voltage as well.

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[johnhill]

I feel terrible that I am really enjoying watching you solve this complex problem... sorry for your pain ... but glad it not me. good luck.. I can hardly wait to see the solution. THANKS for video

[MrEroshan]

Man after seeing all your troubles I feel blessed that my system has been up and running for 6 years now without a hiccup.

[sailaway]

For a brief moment i thought your problem was related to one I had a couple years ago but now I think not. My system, five one hundred watt panels connected in Parallel mounted on stainless steel rail on my sailboat. I purchased used 100 watt from another sailor. Mounted it just around sunset pretty simple Parallel to others. Next day system seemed low but I shrugged my shoulders had another beer. Day three holly crap my stainless steel swim ladder pitted badly zinc almost gone on propeller shaft. Somehow my new/used panel was sending current through panel frame mounted on steel grounded rail with other panels. I returned the panel and life was good again. Love your channel

[MickBasterd]

I'm writing this before I finished the video, so forgive me if I speak out of turn, or if I state something you already covered:
One underperforming panel will bottleneck ALL the others that are on the same circuit. Likewise, shadows on one, will force the others to operate at a reduced output. Because of this reason, it's generally advised to have separate charge controllers for each "bank" of panels that are in the same location/facing the same direction. For example, you should, at the very least, have one charge controller being fed from the panels on one side of your roof, and another separate charge controller for the panels on the opposite side of your roof. This methodology can also be applied when a string of panels is in the shade more often than the other strings. Again, shade on ONE of your panels or a failed panel, will limit all output for all panels on that string, hence why you would want multiple charge controllers.

[alanb]

We bought some used panels. They checked out good on open circuit voltage and shorted current. However when charging batteries their output fell far below spec. The panels had enough internal resistance they delivered much less power than spec. You cannot rely only on open circuit and shorted tests, you must test into a realistic load to judge good panels. These panels had internal resistance problems that simple tests would not show.

[maleiot_]

Interesting Video again! You are so motivated to find the fault! To check the diodes, you have do it in removed condition...that means solder out and measure...

[mikefrench]

I found that the cable connection on the mc4 connectors corroded inside. These were the original wires and connectors supplied with the panels. I had to change both the cable and connectors to get them to work properly.

[nigeldunn]

Andy I can offer only four suggestions at this point -

(1.) Take all panels in your west array off the roof and clean them.

(2.) Then in and un-shaded spot connect two panels in series and determine if they work well? If they don't work well try another pair until you find a pair that do work well together then mark them as good! Then test a third panel with the string and replace it until you get a 3 panel string that works well.

(3.) Then remove the last panel you added to the good string and test all remaining untested panels and mark and group the ones that work well separate from the ones that don't. Then compare in detail a good panel with all panels that are bad to try to isolate the problems. If they can be repaired, do so, if not dump all the faulty panels!

(4.) If none of them work well in a string then you will have to start again from scratch by replacing all the panels!

[serversurfer]

“Maybe they got left out in the sun…” 💜😂👍

[ahmedsaffar]

Andy, in the video at 1:36, do you see the other garage roof it is fully sunny while this roof is shaded, it is better to move the west bank solar array

[happymike]

I have a similar problem with one of my off grid systems, can't wait to see what you find, might be the same as mine...

[poolsidedreamer]

Make sure the diodes in your solar panels are installed correctly. Check the positive and negative mc4 connectors are actually on the the correct lines- positive connector on the positive line and negative connector on the negative line - sometimes the lines are reversed at the factory. Panels are not the problem. Don't know what else could be the problem.

[brian]

your whole solar experience summed up." what the hell is going on ". lol you crack me up.

[sreekumarUSA]

Addendum to the below: Eagerly looking forward to the investigation results.

[airpress]

Hahaha, like when you said what a shitshow🤣
I just stumbled on your channel. Very useful channel. I subscribed. Greetings from Belgium.

[wechselrichterschaltungen]

Guten Morgen, sehr interessantes gespannt was rauskommt..viele

[edc]

Something is causing the panels I-V curve to be deformed which is confusing the MPPT, stuff to consider, water ingress, bypass diodes, connections. As a starting point I'd remove all of the bypass diodes, how old are these panels was, MPPT a common technology at the time - perhaps the bypass diodes have characteristics that are confusing the MPPT.

[juancazorla]

Why dont you connect 2 of them in series and then short circuit them, then measure de VOC voltage and ISC current of the both panels connected in series and see if the amps goes down from 4 to 2 .

[antoni_sk]

Hi Andy, we dont know... Can you try interupt bypass diodes ? Or try bypass diodes ...

[PatricksDIY]

That really Sucks Andy :( I am not understanding how all 9 panels could be "bad" I swear when you first put those up you were getting 500 and some odd watts from them, and almost 1200 total from the entire array. its got me scratching my head for sure, I would have done the exact same steps as you, the only other thing to check at this point are the diodes and the MC4 connectors I suppose. Good Luck, We will be keeping an eye out for an update!