I installed 2 10kW 208V powerone inverters this summer and both failed. The first one failed right out of the box and the second made it a few months. We were hired just to install the system by a local firm that designed and sold the system and have had a bear of a time getting paid from anyone.
Jesse On Wed, May 8, 2013 at 12:38 AM, <[email protected]> wrote: > Hi all- While I have not had the failure problems noted with > microinverters, PowerOne inverters have recently given me a big headache. > Installed their 6kW model last November that failed in a month. They > replaced it under warranty, no problem no reimbursement. Then the > replacement failed in March. Again replaced, no problem. But that's the > problem-- there was no indication from the inverter of why it failed. When > the replacement inverter that was installed in March failed in April, they > declared it out of warranty and made me pay nearly $900 for repairs. This > is less than 6 months from initial installation. > All the failures occurred after rainy weather. This time I bought megaohm > meter and checked the wiring. There was a nick in the insulation where a > negative DC home run pulled around a rail corner, with a small but > noticable burn spot. This did not show up with a standard meter check, but > it did with the megger and some watering from a hose. OK, so there is an > intermittent ground fault. With a transformer inverter that would just be a > blown fuse with a ground fault error message. But it seems this inverter > will self destruct with a ground fault. No error message or any other > indication that even PowerOne would or could relate before sending 3 > replacements. > The Tigo monitors indicated that each inverter failure happened at morning > power-up, with minimal solar current. Oh, and having Tigo monitors in the > system but not on the one-line drawing was PowerOne's nominal excuse for > canceling their warranty. They posted a document on their website dated > March 10, right after the second failure, to the effect that when using > Tigo monitors you must disable the inverter MPPT scan so they don't fight. > But didn't tell me, or apparently their tech staff.... > The post-mortem on the last two inverters (performed well after the > replacements were sent) indicated over-current in the IGBTs. So where is > this lethal current coming from? There are only two strings, one each into > this dual channel inverter. There is not enough solar current to kill it > even in broad daylight. But a morning power-up failure can only mean some > AC input surge current sneaks through the ground fault and into the DC > inputs. Sounds like a design flaw to me... There should not be anything > that can kill an inverter other than over-voltage or over-current; and that > would kill it quick, not a month or months later after a rain. > > Can anyone suggest a possible failure mechanism? Surely not the dreaded > electrolytic caps-- the inverter is mounted under a dry eve. > In general, how are transformerless inverters protected internally from > external ground faults? > And the obvious question is: how could anyone trust a company with this > kind of warranty service? > Thanks > Don Barch > Energy Solar > > > Message: 13 > Date: Tue, 7 May 2013 09:03:13 -0600 > From: Troy Harvey <[email protected]> > To: RE-wrenches <[email protected]> > Subject: [RE-wrenches] Dual Channel Inverters > Message-ID: <[email protected]> > Content-Type: text/plain; charset="windows-1252" > > Since we stopped using micro-inverters due to the high failure rate, > network problems, difficultly in replacement ? I've been using the > power-one inverters a bunch because the dual channels solve most of tricky > issues like different roof aspects, shading, and uneven strings. > > However, they are limited to 6kW, which is only mid sized in todays world. > I'm constantly having to design 7-12k systems in residential applications > all the time. Any other dual channel inverts of the market for 240VAC? I > remember back a few years ago that sharp had a 3-channel inverter. Doesn't > look like it is still around. > > thanks, > > Troy Harvey > --------------------- > Principal Engineer > Heliocentric > 801-453-9434 > [email protected] > > > > _______________________________________________ > List sponsored by Home Power magazine > > List Address: [email protected] > > Change email address & settings: > http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org > > List-Archive: > http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org > > List rules & etiquette: > www.re-wrenches.org/etiquette.htm > > Check out participant bios: > www.members.re-wrenches.org > > >
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