DarthPuppy
Posts: 733
Joined: Sun Aug 11, 2013 8:45 pm
Delivery Date: 11 Aug 2013

Reduction from golf ball damaged panels?

Sun May 10, 2020 4:06 pm

We back up to a golf course. Over the past 7 years, we have 4 of our 30 panels that have taken bad golf ball strikes which have fragmented the glass throughout the panel with sizable cracks surrounding the impact point - basically a small crater.

I'm wondering how bad the production loss is likely to be from these 4 damaged panels.

We don't have the micro inverters on each panel, just 2 central inverters. On an inverter string, does each panel perform without regard to the other panels? Or is their output reduced to that of the lowest performing panel on the string?

If all panels on the string are reduced, then I'm thinking it would be prudent to go ahead and spend the money to replace the 4 damaged panels. If the only impact to the production is that 4 panels produce a little less power but the rest of the system is unaffected, I'm not as inclined to spend the money. If the likely result is that 4 panels produce no power, but that doesn't impact the rest of the string, then I have some more thinking to do.

Advice?

Thanks!
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Oilpan4
Posts: 1771
Joined: Wed Jan 09, 2019 10:51 pm
Delivery Date: 10 May 2018
Leaf Number: 004270

Re: Reduction from golf ball damaged panels?

Sun May 10, 2020 4:33 pm

On a string inverter any current reduction in one panel is going to limit all panels.
You may be better off bypassing those panels till they can be replaced, as long as the remaining panels can build up enough volts to power up the inverter.
I like string inverters because they're cheap, but they suck with shading and coping with a damaged or degraded panel.
For example, a single large oak leaf could land on your array, cover 1 cell and juat about cut that strings production in half, assuming that sting is going to its own inverter.
If you have 2 or 3 stings going into 1 inverter that string of panels will pretty much drop all production. But it depends on the panels and inverter.
Micro inverters, although expensive they deal with shading and damaged panels well. You only lose production from the one panel.

DarthPuppy
Posts: 733
Joined: Sun Aug 11, 2013 8:45 pm
Delivery Date: 11 Aug 2013

Re: Reduction from golf ball damaged panels?

Sun May 10, 2020 4:48 pm

Thanks for the response.

It sounds like it definitely makes sense to do something. I like that bypassing idea.

I will go ahead and request a quote for the panel replacements. I will also inquire about cost to simply bypass the 4.

How difficult is it to do a diagnostic to identify the output of the damaged panels versus the rest of the panels?
'13 Leaf SL
'18 Honda Clarity Touring PHEV

Oilpan4
Posts: 1771
Joined: Wed Jan 09, 2019 10:51 pm
Delivery Date: 10 May 2018
Leaf Number: 004270

Re: Reduction from golf ball damaged panels?

Sun May 10, 2020 5:06 pm

On a string inverter it's actually pretty difficult to trouble shoot the panels individually because of the very high DC voltage you get working on energized panels.
They would probably run the string with the bad panels by passed, assuming their lowered voltage output will power up the inverter, then add in 1 bad panel at a time and see what the string amps are.
At least that's where I would start. I'm no stranger to lethal voltages.
You may have 1 or 2 maybe 3 panels that are cracked but still work good and it's all in 1 panel.

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