Issue with 7 yr old panels?

[Kevcam12]

Hello All,
I’m new here and I want your opinion.
My solar panels are 7 yrs old Chinese made from Canadian Solar. I contacted my installer to asked his opinion on 3 of my 3.0 kW panels. I showed him the same photos of approximately 2-3” smooth to the touch, from I thought was a anomaly. He said that was unusual but after checking my system that everything is still outputting power. I thought since the panels are still under warranty perhaps I could get them replaced. Also what do you think it is?
I live in So. Cal.
Peace

[bob-n]

Are you certain that those defects haven't been there all along? If you're certain, then it is clearly a failure of some sort. Perhaps it is an internal stress fracture.

Unfortunately, warranties don't cover cosmetic defects. You have to show that the output is degraded.

Does your reporting system measure the output of each panel, or just the total output of the system? If you can't tell the output of each panel, then it's really hard to know whether it's working correctly vs giving reduced output. "...still outputing power" doesn't mean much. It could be that those three panels are putting out nothing and the rest are still producing. That would clearly be a warranty defect.

Do you personally have access to the reporting, or is the installer the only one that sees the output? No matter what, you should demand that the installer give you access to live system information on your own computer.

If you can get records of the system output over the past 7 years and can see a drop of more than 10%, you have a clear warranty case.

It's likely that all of your panels are wired in a string. If you can disconnect one of these bad panels, replace it with a short circuit, and see no change in system output, you can be sure that it's a bad panel. If you can't do that yourself, unfortunately, you will have a $200-$300 labor charge for someone to run that test. (That's a wild guess on cost - I could be far off depending on your local labor market.)

You can buy new panels for approx. $250 each. It might be less total hassle to just replace the panels yourself. They are standard size and simple mounting and wiring. Again, I'd estimate a few hundred dollars of labor if you can't do it yourself.

If that makes the system work much better, then you MIGHT be able to go back to the installer and say "See, it's definitely bad panels. You owe me." But don't hold your breath on getting reimbursed.

By the way, it's very unlikely that the panels are 3kW each. It could be that your whole array is 3kW. These days, panels are in the range of 300W to 400W. They were somewhat less 7 years ago. If you have 12 panels at 250W each, that would be a 3kW array, and would seem about right.

[Kevcam12]

Hi Bob,
I was thinking about your comments and being about to more clear with my panels. Each panel is 255 watts for a total of 3.5 kWs. As of now it looks like the panels are delivering juice. I don’t have the records to show since day one what is my degradation. Also if I need to replace my panels are they easy to replace and the panels reconnect and recognize the emphases inverter?

[bob-n]

It is likely that your panels are close to standard size and standard connection. Standard panels are roughly 64.5" x 39" but I've seen them as wide as 66.3" and as long as 39.4". Panels also vary in thickness (32mm to 40mm) and color. Yours are black. Measure yours and then you can contact a dealer and have them match the dimensions.

The Enphase inverter recognizes new panels with ease. It sees two wires with DC and pulls out power. You don't do anything other than plug it in.

If you can walk on the roof, replacing panels is fairly easy. The hardest part is carrying a large 40-pound panel up the ladder to the roof by yourself. With two or three people, it is much easier.

Each panel has two wires, each with its own plug. Each panel is probably attached with four bolts. Unscrew the bolts, lift up one edge of the panel, unplug the two wires, remove the whole panel, then do the opposite to replace it.

The plugs probably have safety latches. Either you need a cheap, special plastic tool or you need two small screwdrivers and a little fiddling to remove the latches, allowing you to remove the plugs. The dealer who sells you panels can also sell you the special tool. The plugs can only mate one way, so you can't connect it backwards.

I can't comment on your specific bolting system, but it's probably like all the rest. If you've replaced spark plugs, you'll have no trouble with the bolts. Like spark plugs, the bolts are torqued to a specific tightness, but the torque is much lower than you might expect. You need a low-range torque wrench for it. The $15 Harbor Freight 1/4" torque wrench is good enough. For my system, the torque spec is 20 inch-pounds. That's like 1/10 of the torque of a spark plug.

[J.P.M.]

Without documentation about how the panels were received and more importantly without some documentaion of prior performance and so any performance degradation to back up a warranty claim, you may be in for a hard time.

I'd first determine how those suspect panels are performing relative to the otheres in the array. If that are +/- maybe 5 % or so, I'd leave things like they are.

Do you have a central inverter, microinverters or optimizers ? How to test on your own will depend on what you have for inverters. Central inverter systems without optimizers do not allow individual panel monitoring. The other two types do. If you do not know what you are doing - put ypurself under a D.N.F.W. (Do Not Fool With) order.

With central inverter systems, even with documentation, and because system output can and does vary by the second as f(weather), mostly irradiance, without very detailed and time matched weather (including site generated irradiance data) and system output documentation, central inverter system performance documentation, as different from panel performance documentation such as might be available with microinverter or optimizer equipped systems won't yield much information that's useful.

I'd read the panel warranty very carefully, particularly about output degradation. Sometimes that gets slippery and different than, for example, 0.5%/yr. degradation or such as folks are often led to infer. Also, what does the panel warranty say about claim documentation requirements ?

Without photos or other proof such as installer's notations of defects, I'd be prepared to answer questions about when the defects appeared and linking those defects to any performance degradation.

From what you write and how you write it, given what sounds like your level of knowledge and experience, I'd suggest you consider any panel replacement get farmed out, maybe to the original vendor if they are still in business. You may have some trouble getting an exact match, but it looks like there are Canadian Solar 255 W panels available. Compare data sheets for what you have and any potential replacement and get close. Depending on your inverter setup, getting close to the original panels in terms of voltage and STC output is at least a good idea. How close ? For you, those things are best left to a qualified and licensed electrical contractor who is familiar with and installs PV for a living.

Id first determine how the 3 panels are performing relative to the others. If they are within a few, maybe 5 % or so, I'd leave them alone.

[bob-n]

Kevcam12: You said "emphases inverter". Do you mean "Enphase" brand inverters? If it is Enphase, then you will see the name Enphase on the report or on the app or on the website where you get data from the system. Enphase makes "microinverters". Enphase microinverters are small boxes placed on the roof, one under each panel. If that's what you have, you're in luck, because as JPM says, these give information on the output power coming from each individual panel. From an Enphase report, it would be very clear if one panel was weaker than all the rest.

Do you have a big box as part of the solar system, at ground level? If so, can you tell us the brand name on that box? Extra credit if you can find a model number.