I have 42 SolarWorld 250 watt panels with Tigo boxes. The other day my B string failed while the other 3 are still running fine. There are 2 Sunnyboy inverters as well. There appears to be no obvious cabling issues. I tested the gateway, power cycled the inverters and the power modules. I have sent the string failure warning email from Tigo to my installer.
What could cause a string to fail?
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Almost always a bad connection somewhere. Most likely in the home run wiring or intermodule wiring, but potentially inside a panel. With about 10 panels in series there are well over 600 connections involved. Kind of the downside of high-voltage string inverters. I'm not familiar with Tigos but I assume that if a panel fails, the Tigo will allow the string to keep going so hopefully that limits the problem to just the external wiring or the Tigos. One possibility is that not all "MC4" connectors are as compatible as you would think. If your installer used one brand and the panels use a different brand, they might not be making good contact. Even with both connectors being the same brand, there isn't a whole lot of contact length on these connectors. Looking at the connector, you would think that there is contact over the whole length of the 1/2"+ connector snout - but the actual contact length inside is really only 1/4".
Be sure and let us know what the installer finds....
BSEE, R11, NABCEP, Chevy BoltEV, >3000kW installed -
Hi all ,i have had a 3.2kw system for 3 years now,i live in south west UK ,system has worked well and i'm very pleased with return ,only problem i have encountered is i have lost one of the two strings for 24hrs when temperatures are in the low 30's ,1/7/15 and again yesterdayalmost to the year 19/7/16 the knocked out string starts working the day after the extreme heat ,so i have lost half my input for only 2 days out of the 3 years but was wondering if anyone could tell me why this happens in extreme temps ,thanks AndyComment
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Hi all ,i have had a 3.2kw system for 3 years now,i live in south west UK ,system has worked well and i'm very pleased with return ,only problem i have encountered is i have lost one of the two strings for 24hrs when temperatures are in the low 30's ,1/7/15 and again yesterdayalmost to the year 19/7/16 the knocked out string starts working the day after the extreme heat ,so i have lost half my input for only 2 days out of the 3 years but was wondering if anyone could tell me why this happens in extreme temps ,thanks AndySunnyBoy 3000 US, 18 BP Solar 175B panels.Comment
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I'm going to +1 on the home run failure due to the fact that if it was an optimizer/module (is this a tigo optimizer install??) failure it would be able to bypass the bad component. If you can give more information like where the strings are combined (soladeck??) we could give you some more troubleshooting information. Otherwise if it is in warranty you may be best served by your installer as this seems like an install issue.Comment
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Well it turned out to be something fried on a circuit board in one of my inverters. SMA is sending a replacement board. They don't feel it was a lightning or a hit from the grid.42 SolarWorld 250W Mono's, 2 SMA 5000W invertersComment
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Powerfab top of pole PV mount (2) | Listeroid 6/1 w/st5 gen head | XW6048 inverter/chgr | Iota 48V/15A charger | Morningstar 60A MPPT | 48V, 800A NiFe Battery (in series)| 15, Evergreen 205w "12V" PV array on pole | Midnight ePanel | Grundfos 10 SO5-9 with 3 wire Franklin Electric motor (1/2hp 240V 1ph ) on a timer for 3 hr noontime run - Runs off PV ||
|| Midnight Classic 200 | 10, Evergreen 200w in a 160VOC array ||
|| VEC1093 12V Charger | Maha C401 aa/aaa Charger | SureSine | Sunsaver MPPT 15A
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I have 42 SolarWorld 250 watt panels with Tigo boxes. The other day my B string failed while the other 3 are still running fine. There are 2 Sunnyboy inverters as well. There appears to be no obvious cabling issues. I tested the gateway, power cycled the inverters and the power modules. I have sent the string failure warning email from Tigo to my installer.
I did frequently have lower than ideal insulation values on my Power One Aurora main inverter (10 M-ohms instead of 20, but that's a main inverter or cabling problem; perhaps rodents bit through the cables somewhere), but it's not a Tigo problem.
Based on the fact that your entire B string was down, it seems it was either a cabling or connection issue with your B string or it was a main inverter issue with one branch of your Sunnyboy inverter. In either case, it doesn't sound to me the Tigo optimizers were the source of your problem.Last edited by Qtips; 10-26-2016, 04:20 PM.Comment
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