First System Build Thread - Another 71kwh DIY

[Disturbedfuel15]

Time is of the essence but I wanted to get a thread out here that I can update and receive feedback on! You've seen this before, I think two other members on this forum have started threads for their CATL module builds. So I won't go into what they are too much other than to say each is 20s, 3.2v. So I'll be doing the needful and carefully disconnecting four of the cells from each of the four modules, resulting in five 48v banks.

I realized I've been reading and reading and reading and reading BUT there are still so many options, I get analysis paralysis!


So I'll keep researching but if anybody has an opinion, please share! The only opinion I'm not wanting is 'You should have bought individual cells'. Honestly, I get that and I somewhat regret my decision, but not entirely. I felt pressured that these cells would not be around long and it was a rarity, so I bought them. It is what it is!

What have I purchased so far?
-Four CATL 20s 3.2v modules
-Five JK-B2A24S20P BMS with the optional push-button to turn them on
-35ft of 4/0 pure copper welding cable (I have a DIY electroplating setup from a past project I'll use for nickel-plating ends that touch aluminum)
-4/0 (1/2") pure copper battery lugs
-25ft roll of 3:1 marine-grade, double-walled, adhesive heat-shrink
-Tripp-Lite SR25UB server rack (3000lb static/2250lb rolling capacity)
-3/8"x1"x48" steel beams (making four 19"-wide support brackets, attaching to rear of CATL modules via 7/16 grade 8 bolts/locknuts) (for rack mounting)
-120v floor-mounted winch (paired with a pully system, saved my a$$ getting these 350lb modules to the basement. Will use for racking modules as well)
-Warn Pullzall winch (was on sale, figured I could use it to help guide the modules into position in the rack)
-40 235w Trina 'cracked vinyl' solar panels

I think that's about it. My idea is to run the house completely off of battery/solar from the hours of 1-7pm, because that is peak rate hours. Of course it would be nice to completely run off battery and solar 24/7. I want to do everything myself as I am very capable, but I understand some things, like if I wanted to sell back to the power company, would need to be installed/inspected by a credentialed electrician. I already spoke to my village president, asking him who I should talk to and what permits I'd need and he told me two things: #1 "I don't give a sh1t what you do, it's your business." #2 "The county electrical inspector will probably want to get paid." For what it's worth, I live in a very rural area, if that didn't make it obvious. I do know I will have to take some aspects of this more seriously than just that statement, but there's some backstory.

I heard you all like pictures, so I'll go ahead and post plenty of 'em! Thanks in advance for any help you can provide. I'm thankful for this forum and I'll definitely donate to it with extra funds after all is said and done. One last message here--I am what some would call a 'slow-DIY-er'. I do more research than is necessary, so don't expect this to move extremely fast! Although having a wife and kid wanting space back in the basement does motivate me a bit more ?




















Whoops, can only attach ten files! I'll post more.

 

[Disturbedfuel15]

More pics!













A question for the solar panels--Should I attempt to repair the cracked vinyl? I've worked with mass-loaded-vinyl (MLV) before and I've taped the seems with special vinyl tape. Obviously that was for an indoor, behind-drywall project, so I know the tape wouldn't hold up outdoor. Perhaps some sort of butyl-tape? Or should I just not worry about this? Santan solar said it should be cosmetic only and they have a 1-year warranty, but I want to PM (preventative maintenance) these as much as possible (if necessary/worth it) before installing them on my roof.

 

[Rednecktek]

See! I'm not the only one who's a post picture pusher!

What about a thin coat of the polyurethane floor coatings they use on gym floors?

 

[Disturbedfuel15]

See! I'm not the only one who's a post picture pusher!

What about a thin coat of the polyurethane floor coatings they use on gym floors?

You know that got me thinking about things I have on hand. I forgot I have a bunch of this 'Big Stretch' sealant that is rated for outdoor use. I think I'll slowly apply that, maybe a couple panels a day. Nothing that will break my back or put me out.

I also saw a thread discussing the exact same thing and it was suggested to use 'flex seal' and I know this stuff is about the same thing without the billy mays hays dude on the commercial backing it XD

 

[Disturbedfuel15]

I still haven't quite decided if I want to go with micro inverters or a single string inverter. I kind of like the idea of being able to monitor each panel individually. I have read the whole sun/shade difference between micro/string is becoming increasingly narrow.
If I went with micro inverters, I'd probably go with Enphase just because it's what's most popular and they have a long warranty.
If I go with a string inverter, I'd more than likely go with something midnite solar offers or a sol-ark.
I also like being more in control of individual components, since I'd need a battery charger/dc inverter separately if I went the micro route, rather than an AIO inverter+charger. I think I have that right, but please correct me if I'm mistaken. One thing that I haven't discovered yet, and is a 100% make-or-break for me, is whatever I go with must be able to transfer from grid to battery if the grid goes down. I'm still researching ATS's and the like!

The BMS's came in. I figured it was a good enough opportunity for a few more photos as well!

 

[Hogheavenfarm]

I would just spray the backs with flexseal, a few coats should be just fine, its on the back and wont see any direct sun, so UV should not be an issue.

 

[Disturbedfuel15]

I would just spray the backs with flexseal, a few coats should be just fine, its on the back and wont see any direct sun, so UV should not be an issue.

Man, I feel like I'm going to need a lot of cans to cover 40 panels. IT would be the easiest way, but easy does not equal cheap does it? They also have a 2.5 gallon pale I could roll on for $225. People warn you have to do it all in one sitting or else it will more than likely rubberize itself in the can. So I don't think I'll do that. I didn't want these panels to turn into a chore, hence doing a couple day with stuff I have on hand. At first glance I see I can get a 6 pack of flex seal spray for $90. Each can covers 12sqft. Each panel is about 8sqft * 40 = 320sqft / 12 = 30 cans / 6 pack = 5 of these 6 packs = $450.
So I can either go with the stuff I have on hand = free but more laborious
Flex seal = $450 but easier to simply spray over the cracks

Honestly, I want to get the battery portion going before solar. I want to be able to run my power-outage-prone house off of batteries ASAP. So my immediate research topics revolve around that. I don't know if I want to go AC or DC coupled. By that, I've read DC-coupled means a hybrid inverter that can handle both solar and battery. Whereas AC-coupled means a separate solar inverter and battery inverter. I worry about everything being able to communicate with each other in an AC-coupled system.

There are just so many options, it's tough to figure out which way to go.
As I said before, I think I want to go with microinverters for solar and then a battery inverter/charger for my batteries. I could be talking out my ass, though. Don't know enough to say. I don't expect to be spoon fed so I'll get back to the research.

 

[Disturbedfuel15]

Alright I've got some updates, although no pictures--Sorry!

I have purchased two Sunny Island 6048's. I'll do the Sunny Boys when the time comes to hook up the panels.
I'm getting a tree removed in my backyard so that I can do ground-mount vs roof-mount.
I ordered the flex seal after looking at the backs of the panels again. There are just too many tears for caulking to be a good idea.

I'm regretting the JK BMS purchase as SMA does not mention JK at all, and I can find almost no mention of SMA and JK being together. I realized I can still use the JKs and monitor the batteries via the app, so not all is lost. I'm having a hard time figuring out exactly what the advantage is of the inverter being able to talk to the BMS. As long as the BMS can utilize the inverters to draw power from for the batteries to charge/balance, what more is there? Say I go ahead and replace these five JK BMS with REC, how will my experience change?

 

[Disturbedfuel15]

Note, I understand an inverter is actually an inverter+charger in this case, but I'm not going to type the every time.

SO, for instance, from this thread https://diysolarforum.com/threads/jbd-overkill-bms-can-bus-comms-support-for-inverters.54964/
all of the following can now be sent to the inverter (for example):

• Battery Voltage
• Battery Current (+charge, -discharge)
• State of Charge (SOC)
• State of health (SOH)
• BMS Temperature
• Charging Voltage
• Charging Amps
• Discharge min Voltage
• Battery name
• Alarms: Cell over/under voltage, Charge/discharge over current, High/low Temp, BMS fault
• Charging logic: Complete rework of the charging logic, now charges with constant current(CC) to the absorption voltage, then has an absorption timer (Constant Voltage, user configurable time), with rebulk feature (user configurable offset from absorption voltage).

By the way, that's awesome, kudos to him for that work.
But why would I care if all of that information gets sent to the inverter when I can view all of it via the app/bluetooth? My best guess is that the inverter can utilize these values to best charge the batteries...but that doesn't make sense to me because doesn't the BMS determine how the batteries are charged and balanced? Again, isn't it just requesting power from the inverter, where the batteries need it? I feel like it's a case of the battery speaking one language, the inverter speaking another, so a BMS is brought in to not only manage the battery, but translate what it requires from the inverter.

To further demonstrate my lack of understanding, let's say the battery is gasoline and the inverter is a lawnmower. The BMS would be me. As the BMS, my job is to make sure the gasoline is a-okay and I also add the appropriate amount to the lawnmower as required. Why would I care if the lawnmower understands the state of the gasoline or how much I am pouring in? That's my job to make sure the gasoline is good and that the correct amount is added. It's not the lawnmower's job to make sure the gasoline is good, it's mine (as the BMS in this scenario).

 

[Disturbedfuel15]

Updates:
I purchased two SMA Sunny Island 6048-US from ChrisFullPower here in the for sale section of the forum. I'm hopeful he didn't rip me off, although he hasn't replied to my last message nor been active on the forum since I purchased. They look to be in good condition and I never got the feeling like he was trying to get one over on me. I guess we will see once I get them connected to the batteries.

I've also designed the system using the SMA web designer and purchased the required PV Sunny Boy inverter, along with the SMA Data Manager M Lite (which was cheaper than the ridiculous prices people are trying to charge for the severely out-of-date webbox on ebay).
Here are some excerpts from my plan PDF!

Overall plan:


Solar Inverter:



Looks like I'm going to need to buy 'SMA Energy Meter' as well, according to the information provided:
Here is says 'Grid connection is not supported' but I am assuming it means I'm simply not going to be able to sell back to the grid. That's okay, I don't want to sell anything back to 'the grid'.

So now I'm at the point of actually connecting the batteries to the inverters. I'm trying to figure out what fuses/where so I can get going, but nothing about this is straightforward to me!

I purchased Will's 'mobile solar power made easy' pdf, and it has been helpful. I'll use it tomorrow to calculate what fuses I need.
I also purchased the new JK BMS that can communicate with the inverters. I figured why not, they're the same price as the older versions and I'm sure plenty of people around here would be willing to buy the other ones I didn't use.

I think that's about it for now. I don't yet know if I want to mount the battery inverters in the basement, next to the batteries, or if I want to mount them in the garage, with a 10ft 4/0 run to them. I don't know how loud these inverters are.

 

[Disturbedfuel15]

Well I got some bad news from solar flexion (where I purchased the data manager and sunny boy from a few weeks ago). I am calling them back right now. Basically, they have neither of those items and instead offered to upcharge me for the 50 device, multi-cluster data manager (full blown, double the price) and then also upcharge me for the newest SMA hybrid inverter that 'hopefully' comes out Q1 2024.

Back to the drawing board.

I'm going to be honest, I'm having a real hard time not just purchasing a couple Deye or SRNE hybrid inverters. This SMA route is looking to be rather expensive. I have to remind myself that it's going to pay off in the end, but this last blow has me questioning my decisions.

 

[Disturbedfuel15]

I guess I should also say, they offered me a trade for a 'GoodWe A-MS Series GW7600A-MS 7.6kW' as well. This seems preposterous that I'd completely step outside an SMA system so I'll be declining that.

Edit: Just got off the phone, I have nothing bad to say about them besides their site being misleading on what is in stock and what is not. Also not a big fan of the wait to find out portion of that, but they're sending me a refund, so I can't complain.

 

[Hedges]

I'm having a hard time figuring out exactly what the advantage is of the inverter being able to talk to the BMS. As long as the BMS can utilize the inverters to draw power from for the batteries to charge/balance, what more is there? Say I go ahead and replace these five JK BMS with REC, how will my experience change?

With communications, SI should slow charging so balancing can occur without any cells running to high voltage cutoff.
Given a few seconds for frequency shift power control, the battery still needs to be a cushion to absorb a few kW seconds. I have no experience with that because I use AGM.

I guess I should also say, they offered me a trade for a 'GoodWe A-MS Series GW7600A-MS 7.6kW' as well. This seems preposterous that I'd completely step outside an SMA system so I'll be declining that.

Edit: Just got off the phone, I have nothing bad to say about them besides their site being misleading on what is in stock and what is not. Also not a big fan of the wait to find out portion of that, but they're sending me a refund, so I can't complain.

data manager and sunny boy ... they have neither of those items ... upcharge me for the newest SMA hybrid inverter that 'hopefully' comes out Q1 2024.

I'm going to be honest, I'm having a real hard time not just purchasing a couple Deye or SRNE hybrid inverters. This SMA route is looking to be rather expensive. I have to remind myself that it's going to pay off in the end, but this last blow has me questioning my decisions.

Do you have any need for backfeeding grid and the latest grid-interactive features? If not, shop for older model Sunny Boy. So long as they have an off-grid/island mode, the wider frequency and voltage limits should work better, compared to non-SMA inverters.

Look for models with a checkmark under "off-grid systems"

https://files.sma.de/downloads/SB-OffGrid-TI-US-en-23.pdf

Some are transformerless, which can be a problem for PV panels subject to "PID". I'm now using the transformer type (e.g. 5000US) which allow selection of negative or positive ground.

What did you want Data Manager for?
I'm using Web Box to configure SB and SI. I also have Sunny Boy Control but for some reason it only talks to some of my SB, not all SB and not SI.

 

[Disturbedfuel15]

With communications, SI should slow charging so balancing can occur without any cells running to high voltage cutoff.
Given a few seconds for frequency shift power control, the battery still needs to be a cushion to absorb a few kW seconds. I have no experience with that because I use AGM.

Great, thanks!

Do you have any need for backfeeding grid and the latest grid-interactive features? If not, shop for older model Sunny Boy. So long as they have an off-grid/island mode, the wider frequency and voltage limits should work better, compared to non-SMA inverters.

Look for models with a checkmark under "off-grid systems"

https://files.sma.de/downloads/SB-OffGrid-TI-US-en-23.pdf

Some are transformerless, which can be a problem for PV panels subject to "PID". I'm now using the transformer type (e.g. 5000US) which allow selection of negative or positive ground.

I hadn't considered using an older model, but I will now that you have informed me! I only have a few desires as far as 'interaction with grid' and that is the ability to charge from grid, peak-load-shaving, and monitoring of grid power for automatic transfer switching. I've been reading the manual, cover to cover, including many, many posts here on the forum and I know those can all be achieved outside of the Sunny Island/Boy, but if any can be done BY the Sunnys, it's a plus. I have no interest in backfeeding the grid. Solar is also secondary to the original intent--whole home backup. I've got a lot of work to do, including removing a couple trees. I really want to put the array on the ground vs roof, but the $6000 tree removal quote has me in a pickle. Again, secondary. They'll go up eventually, if not little by little.

What did you want Data Manager for?
I'm using Web Box to configure SB and SI. I also have Sunny Boy Control but for some reason it only talks to some of my SB, not all SB and not SI.

I actually might have found another Data Manager M Lite. I just purchased it from a shop in NY. We will see if it ships...I'm noticing these companies will gladly take your money before actually figuring out if the product is in stock.

The reason I want the data manager is for an alternative to the web box. I'd go for either the web box or the data manager, as I believe they accomplish the same thing--monitoring/management via local LAN.

Hedges, thank you for your thoughtful replies. I've learned A LOT from you and have a few of your replies bookmarked.

 

[Hedges]

I don't think US SI has any particular peak shifting functions. SBS does. European SI may.
People have commanded them to cause them to support grid from batteries, etc.
You can use grid as generator, draw from it only when battery gets too low. You might connect a relay and connect to grid only during low rate times or when battery gets low.

Does Data Manager talk natively to RS-485? Or will you put a Speedwire card in SI? I have RS-485 in SI an older SB, for grid-backup. No interface needed for off-grid, but having it allows data gathering. Newer SB may not support RS-485. I have the daughter card for TriPower but haven't been able to talk through that, use SpeedWire and Sunny Explorer.

I've bought a few WebBoxes for $150. Woke up one morning and saw I missed one for $15 (another forum member further East was up earlier.)

Various new and used SB on eBay, sometimes Craigslist. They have a long lifespan but will fail eventually so new or newer is preferred.
I've sometimes managed to buy new old stock for $0.10/W, but mostly you'll see higher prices or used ones. Shipping can be a killer. The transformerless weigh less can go common carrier. Even if you get one that's long in the tooth, there will be future opportunities for more recent models.

Is SSG235P SanTan's private re-label (I think so), perhaps of old Trina panels? (they can probably tell you). You should find out if these are subject to PID, in which case determine if they need negative or positive ground and get a transformer type inverter which can do that.

Is the tree removal problem sufficiently technical that you need proper talent? Or could you connect a cable to pull it (with an offset tug line for safety), cut a notch, fell, etc? And have firewood or lumber. With a chipper, compost.

To me $6000 is 120 man-hours of labor at $50/hour or 50 man hours at $120/hour. Just doesn't compute for me.

 

[Disturbedfuel15]

I don't think US SI has any particular peak shifting functions. SBS does. European SI may.
People have commanded them to cause them to support grid from batteries, etc.
You can use grid as generator, draw from it only when battery gets too low. You might connect a relay and connect to grid only during low rate times or when battery gets low.

Yep, I figure I'm going to have to make most of it happen on my own, via external methods. I looked into Sunny Boy Storage but besides ATS, SI exceeds its abilities in every way. It's kind of a stupid product in my opinion with a very small, niche market.

Does Data Manager talk natively to RS-485? Or will you put a Speedwire card in SI? I have RS-485 in SI an older SB, for grid-backup. No interface needed for off-grid, but having it allows data gathering. Newer SB may not support RS-485. I have the daughter card for TriPower but haven't been able to talk through that, use SpeedWire and Sunny Explorer.

I've bought a few WebBoxes for $150. Woke up one morning and saw I missed one for $15 (another forum member further East was up earlier.)

Correct, it actually has that and more. From the manual, page 18 (https://files.sma.de/downloads/EDMM-10A-BE-en-11.pdf):
"The product is equipped as standard with an integrated webserver, which provides a user interface for configuring and monitoring the product. The product user interface can be called up via the web browser if there is an existing connection to an end device (e.g. computer or tablet PC). Connected SMA products can be configured and commissioned via the user interface of the product."
"The product is equipped with two Modbus interfaces. One interface can be controlled via Ethernet (Modbus TCP) and the other interface via RS485 (Modbus RTU)."
"The product is equipped with a Wi-Fi interface as standard"
"The product is equipped with SMA Speedwire as standard"
I chose not to go with the even more outdated webbox as I don't want to wait until another one pops up on ebay. I had the search saved and alerts setup for any new ones. Turns out maybe 2 a month show up and you'll be damn lucky to get it under $200. I've seen one in the past three months go for much less than that and the seller obviously made a huge mistake seeing as it was swiped up immediately. A broken one sold for $200 only a few days ago The ones I saw for $500 have now been swiped up, too. No thank you.

Various new and used SB on eBay, sometimes Craigslist. They have a long lifespan but will fail eventually so new or newer is preferred.
I've sometimes managed to buy new old stock for $0.10/W, but mostly you'll see higher prices or used ones. Shipping can be a killer. The transformerless weigh less can go common carrier. Even if you get one that's long in the tooth, there will be future opportunities for more recent models.

I'm going to keep my eye out, thanks for the tip. I'm definitely going transformer--I have no interest in anything lightweight and unable to handle large inrush currents. Excellent point on getting something 'good enough' for now and then upgrading in the future, as solar is not hugely important ATM.

Is SSG235P SanTan's private re-label (I think so), perhaps of old Trina panels? (they can probably tell you). You should find out if these are subject to PID, in which case determine if they need negative or positive ground and get a transformer type inverter which can do that.

Correct, they are Trina panels. Trina Solar Energy (U.S.) Inc. TSM-240PA05.18.
I just read up on PID https://www.novergysolar.com/understanding-potential-induced-degradation-pid-and-ways-to-mitigate-it
Very interesting. I had no idea this was even a thing, but it makes sense. Ways to mitigate it? An inverter with a transformer! Perfect.
These panels I purchased seem to be in the middle of the pack as far as temperature coefficient, which means they are not extremely susceptible to PID (as I'm reading). Plus they will be in not-so-hot Michigan climate. I also read elsewhere that the really bad Trina panels were made from 2011-2014 and were recalled. These have 2018 dates on them. Thanks for the heads up.

Is the tree removal problem sufficiently technical that you need proper talent? Or could you connect a cable to pull it (with an offset tug line for safety), cut a notch, fell, etc? And have firewood or lumber. With a chipper, compost.

To me $6000 is 120 man-hours of labor at $50/hour or 50 man hours at $120/hour. Just doesn't compute for me.

I am in a subdivision where I can spit on my neighbor's house from my window. I have an 1/8th acre. The tree I need to remove in the back for ground mount is 45" wide at the base and 145ft tall. It covers my entire back yard and they want to delicately remove it with large grappling arms. I have chainsaws but this one has me a bit shook thinking about felling it. We will see.

 

[Hedges]

Yep, I figure I'm going to have to make most of it happen on my own, via external methods.

Let us know how, and how it works out. Various members in different markets.

I looked into Sunny Boy Storage but besides ATS, SI exceeds its abilities in every way. It's kind of a stupid product in my opinion with a very small, niche market.

Or a large market of zero export + time shifting, all while on grid. Their roots include a lot of offgrid, even if Sunny Boy was their first product, but I think on-grid drives growth.

ABU just lets it provide wimpy backup.

I'm going to keep my eye out, thanks for the tip. I'm definitely going transformer--I have no interest in anything lightweight and unable to handle large inrush currents. Excellent point on getting something 'good enough' for now and then upgrading in the future, as solar is not hugely important ATM.

I don't think GT PV, transformer or transformerless, has anything to do with surge/inrush.
The battery inverter (Sunny Island) will provide that, 11 kW for 3 seconds and 180 amps for 30 milliseconds (to fast trip breakers.)
(Sunny Boy Storage only offers maybe 125% of continuous rating.)

Correct, they are Trina panels. Trina Solar Energy (U.S.) Inc. TSM-240PA05.18.
I just read up on PID https://www.novergysolar.com/understanding-potential-induced-degradation-pid-and-ways-to-mitigate-it
Very interesting. I had no idea this was even a thing, but it makes sense. Ways to mitigate it? An inverter with a transformer! Perfect.
These panels I purchased seem to be in the middle of the pack as far as temperature coefficient, which means they are not extremely susceptible to PID (as I'm reading). Plus they will be in not-so-hot Michigan climate.

That's why you're here! Where I learned about PID too.

I was not aware temperature coefficient had anything to do with it. Something to do with level of doping?
I understood it was chemicals in epoxy and glass that migrated into junction.

Also not aware temperature had anything (much) to do with it, rather electrical bias and dirt + moisture forming an electrode. But that link does say temperature. Doubt it affects mobility in silicon much but maybe in the coatings.

But I do understand that positive or negative bias (depending on wafer doping) prevents it. You need to determine which yours want.

I also read elsewhere that the really bad Trina panels were made from 2011-2014 and were recalled. These have 2018 dates on them. Thanks for the heads up.

Their issue I thought was leakage of current to frame.

I am in a subdivision where I can spit on my neighbor's house from my window. I have an 1/8th acre. The tree I need to remove in the back for ground mount is 45" wide at the base and 145ft tall. It covers my entire back yard and they want to delicately remove it with large grappling arms. I have chainsaws but this one has me a bit shook thinking about felling it. We will see.

Get the wood milled and built into a house somewhere with 8 acres.

My trees used to be that size. They've added a foot or two in the time I owned them.

 

[Disturbedfuel15]

I don't think GT PV, transformer or transformerless, has anything to do with surge/inrush.
The battery inverter (Sunny Island) will provide that, 11 kW for 3 seconds and 180 amps for 30 milliseconds (to fast trip breakers.)
(Sunny Boy Storage only offers maybe 125% of continuous rating.)

You're right. I still do not want to deal with transformerless inverters. It seems cheap to not have a transformer in an inverter.

I was not aware temperature coefficient had anything to do with it. Something to do with level of doping?
I understood it was chemicals in epoxy and glass that migrated into junction.

I got it confused, you are right. I was reading this link and mixed it together with PID. https://www.solarquotes.com.au/blog/the-truth-about-solar-panel-performance-and-temperature/

But I do understand that positive or negative bias (depending on wafer doping) prevents it. You need to determine which yours want.

This is what I found:
7.2 INVERTER SELETION AND COMPATIBILITY
• When installed in systems governed by IEC regulations, Trina Solar modules normally do not need to be electronically connected to earth and therefore can be operated together with either galvanically isolated (with transformer) and transformerless inverters.
• Potential Induced Degradation (PID) is sometimes observed in PV modules due to a combination of high humidity, high temperature and high voltage. PID is most likely to cause degradation under the following conditions:
a) Installations in the warm and humid climates
b) Installation close to a source of continual moisture, such as bodies of water
• To reduce the risk of PID, we strongly suggest that modules feature Trina Solar’s Anti-PID technology, which can be applied to any Trina product. Alternatively, we recommend the use of an inverter that includes a transformer as well as proper grounding of the negative DC leg of the PV array.
• Choose inverters with isolation transformers in hot and wet areas (such as shores, wetlands), to ensure proper module function under positive voltage.

Their issue I thought was leakage of current to frame.

I'm unsure of this, I only read they were recalled