I always end up with the real head scratchers. I guess that because what normally stumps most people, I can ussually figure out.. but not this time. Here is what I am running in to. Yesterday our GT3.3 (positive ground) inverter started to act strangley, well actually it didn't start at all and that was the problem. It was a rainy day, but we ussually get about 3 or 4 kilowatt hours on a rainy or heavily overcast day and that is exactly what happened the day before. Yesterday it did not come online it just remained frozen as if it saw no power from the array and GT-View was stuck on the previous days output information. My father was the only person home so when he noticed he disconnected the inverter using the ac/dc combined disconnect switch underneath the wiring box. He waited about a minute and then turned it back on. When he did, nothing happened except it turned on and then displayed "INVERTER OFFLINE" with no other information or fault codes. I came home from work early to check it in the daylight. My multimeter said the array was putting out about 310 volts at 0.65 amps at the time as it was raining. I also touched the case by accident while touching the negative wire (positive grounded system) and gave myself a hell of a shock so I know there was plenty of juice to start the inverter. The AC was at 239.9 volts or something close to 240, not out of range. It should have been producing power, but instead it just read offline. Another thing I noticed is that the inverter would not power up at all without AC power. If I remember right, the display will work even without AC power, but in that case it should have AC Voltage Fault. It never gave me a DC fault warning either. When I disconnect using the main AC/DC disconnect I would suddenly get a red light for GROUND FAULT, but as it only did this when the inverter was in the off position and the light faded out after 5 seconds or so I decided that must not be a problem. When I turned the system back on it went back to the "INVERTER OFFLINE" message but no ground fault detection was flagged. I also tested the fuses at the array combiner box and the ground fault fuse and AC fuse with my continuity tester. Those were all fine as well. I called for support but by then the business day was over and the tech who's number I was given had gone home so I gave up for the night. This morning it was still raining out, and darker than it was when I was testing the system durring the previous day... HOWEVER the inverter came online this morning like normal at about 5:45am with almost no light. It would not work the previous day at 3:00 PM when it was much brighter out. It now seems to be online and functioning normally. What do you guys think could have caused this hiccup? I have never had a previous problem and we have produced almost 5000kwh since the inverter was commisioned on 3/18/08.

at first i though you may have had a lightning emp blow out something in the inverter, but to reset itself and work the next day says something else is likely amiss here. there still may be a problem with ground that the saturated soil may have exposed. i'll bet there wasn't any rain when it restarted. soil resistance drops when that much rain has occurred.

Actually if I recall correctly it was pouring out and the ground was still saturated... actually its still pretty saturated, yesterday was the first day in a week without rain but this was the only day that the inverter didn't work. We did notice something strange though, when I went out to move the array (we track the sun by rotating solid pole mounts by hand) the AC line frequency fluctuated. Not that it helps or makes any sense, but it did. I think there may be a lose connection somewhere. My father pulled a fresh birds nest out from under the array the other day, maybe the bird that built it losened something.

if you mean the frequency from the gt inverter varied, then that's a real problem as it will go out of sync with the utility ac and shut down. the frequency normally should not be varying either on the inverter or the utility. i don't think the bird's nest caused that, but who knows as stuff happens. if your utility is having frequency problems, it may have gone too far out of the range of the inverter and essentially shut the system down also.

If your still having issues, I'd suggest you hook-up a PC and SG-View and start logging ... this will save all the AC and DC parameters during the day and will help pin point any issues you may have and their cause.

On the logging , the faster, the better ... I use 1 second interval

I do use SG view and Its great . That is where we saw the AC Line fequency fluctuate when I moved the array. It only fluctuated about half a hz or so. I didn't actually see it, I was moving the array. I have noticed that if no current comes in from the array and everything is offline, it displays the AC frequency as 0.0hz. The day we had problems it displayed the frequency as 7.9hz or so... way way off since the Skystream Wind Turbine told us our AC frequency was varying between 60.1hz and 59.9hz at the same time. I still have not recieved a call back from the Xantrex technician in Canada I called the other day either.

Data is only logged and valid when the unit is in operating mode and/or has valid DC voltage ... so if internally the unit does not see the Array voltage SG-View won't log anything

Call the Xantrex 800 number ... no sense waiting if the unit is dead

After 100's of installs, I have seen a small number of Xantrex GT series inverters do all kinds of weird things. Even if they do come back to life for a brief period of time, weirdness usually means failure in a short period of time. Fortunately getting a replacement unit from Xantrex is usually not a problem.

Unfortunately it was the last Positive Ground inverter Xantrex had when I bought it and they had to dig it out of the back of a warehouse to get it to me. The inverter did it for a second time this morning. Bright and Clear sunny day with a blue sky. Hasn't rained in 3 days. I checked all the wiring and wiggled what I could with no difference in the inverter. It displayed an AC line fequency on GT View of 7.4hz and MPPT of 600v. It also displayed the lifetime total KWH and the previous days total, almost 20KWH. It would not come online so I tried something a little unorthodox that has worked for me on countless other electronic devices. I smacked it twice next to the display on the faceplate. When I did this the display dissapeared for a moment, then came back up and displayed the firmware version and region number, then all the syncronization/anti-islanding settings, then said connecting in 254 seconds... been working fine since. I will call Xantrex again about it. I think it has a relay sticking or something.

Remove the covers on the BOS and also the cover on the LCD ... make sure the AC and DC wires are tight in the connectors on both the BOS PCB and the connections to the inverter ( under the LCD cover ). I had a GT5.0 that over time the wires got loose. When I found the problem, I went and re-checked all 3 of my units and found most connections had become less than tight, compression of the stranded copper I guess ...