DC Optimizers Failure Rate?

thextthext Registered Users Posts: 2
Hi folks - any installers out there experiencing more than "normal" amount of issues with malfunctioning dc optimizers either Tigo ro SEDG?  Trend?  Experience?  Solution?  Thank you! 


  • mike95490mike95490 Solar Expert Posts: 8,877 ✭✭✭✭✭
    I'd heard of several instances where unschooled labor was carrying bundles of optimizers by their power cables, and the stress ruined most of the weather-sealing, and in a couple years, whole arrays died.  Handled properly, it's only the odd one or so, that goes bad.

    Powerfab top of pole PV mount | 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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  • billybob9billybob9 Registered Users Posts: 141 ✭✭
    I think the SMA Tigo was basically made to limit the amount of voltage (600VDC) going into the SMA RS box and SMA 5.0 Inverter. To pay for optimizers when you have no shading Issues is in my opinion, too expensive. You're better off just removing one panel from each string on your array to stay below 600VDC. 600VDC is the limit you can go with the SMA RS box as the Panasonic Relays inside is not rated beyond this point. So 7 panels of 300W - 320W would put you in the safe zone per string. Max of 2 strings.. 4.2KW or 4.48KW system. To try to get closer and add a 160W panel to seven 300W panels would get the voltage down to a point less then 600VDC but would also bring your Amperage down to the 160W panels Amperage ( almost half of the 300W Panel ). Thus cutting Wattage almost in half.
  • thextthext Registered Users Posts: 2
    edited September 2019 #4
    Thank you billybob9 and mike95490 - the reason for my question stems from need to be nec compliant for rapid shut down 690.12.  when doing a 300kWp - 1.5MWp on a ballast roof mount.  Does anyone have positive experience using Tigo optimizers on similar projects?
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