New PV Panels Making only 72% of Nameplate Rating

[MWeiss]

Was able to get some tests done today. I verified a 1071W/sq mtr irradiance on the panels first.

Then took some measurements as follows:

V load = 146V
1800W each isolated string (one string connected ony)
short circuit amperage of one panel: 12.5
running current (into charge controller) 12.6a

There were some passing white clouds so some variation in data may be apparent. It started to get more cloudy as afternoon arrived. Some of the high peaks were due to clouds acting as sun reflectors.

 

[MWeiss]

Well I'm grappling with a decision. Do I accept a 20% refund and live with a reduced PV output (and 8 more panels to install and so reduce my other array), or do I hold out for replacement of all panels and have to go through the headaches of taking down the 8 I've painfully installed?
If I install the rest of the 16 panels purchased, that will reduce my total solar production by 1200W. The only advantages are that the panels are all mounted above the shadow zones for Dec/Jan and will not lose 40% of their production due to lower third in shadow of buildings.

It's likely that holding out for full replacement would just be too much of a hassle at my age. At the same time, I'm reluctant to install the other 8 panels, though I need to do something about the aging Trina panels. The new configuration is also aerodynamically better, given slightly less area and 5" space between panels. But it's low light performance is much worse than the old Trina panels.

But then these new panels are only performing on the par with the 450W panels, though larger and rated at 550W. Part of me wants to rip this whole thing out and start over with new panels that actually produce 550W and work well in low light like the 450W panels bought in the prior year from same vendor. I know I'll never be happy with accepting the 20% refund and living with reduced power production, but I'm too old to be fighting this battle, especially after the recent heart attack. My wife said to put back the 20 small Trina panels and sell the new panels, but I said I'll never get my $3795 back out of them and all the extreme effort to "upgrade" will be a total loss. It was a LOT of struggle taking down the old panels and putting up the new ones as I'm no spring chicken.

Another part of me says to invest in more batteries, but I've already spent the money on these 16 panels. I hate indecision!


NEW PANELS




OLD TRINA PANELS

 

[Bluedog225]

Tell them you’ll accept their offer for a 50% refund. That way you can feel good about your decision.

 

[yodamota]

did you try another charge controller? might be a long shot but if its easy enough to swap it out.

i would be pissed about the missed solar. especially on those big 550w panels. which are heavy/large to deal with.

 

[MWeiss]

I'm using the same charge controller that happily produced 4000W with the old panels. The nagging feeling is that because that controller wasn't "born" with that array (like my other controller was ONLY connected to a 7200W SunGold array), the though that the controller is somehow "trained" on the old array and is not finding the optimum power point on the new array I just can't shake free of. I don't have a spare of that model controller available to try out. I'm still not sure about the short circuit current readings on individual panels. Some of them looked pretty close to spec.

Even a 50% refund won't solve my problem. I would rather have all the panels replaced with proper functioning ones. That would only buy one rack server battery. I'm starting to think I should have invested the money into more battery capacity, rather than upgrading solar panels, but I did so based upon the performance of the 450W panels I installed last year, which are a game-changer, being my most productive array. That my next batch of panels from the same company could be a dud, well, it just doesn't make sense. I could ask 50% but I think they're not going to grant that.

 

[MWeiss]

There is one more thing I want to try, but I need to buy more Y cables and make some more jumper cables first.

Presently the 8 panels are wired 4S 2P. I'm thinking of rewiring them 2S 4P just to see if the higher current makes the difference. Probably not, but there aren't other options to try.