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EG4 6000XP Showing 50W Solar input during pitch black

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girfold

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Sep 16, 2021
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Hey all, a couple days ago I flipped the PV Disconnect off in prep for thunderstorms - I don't know if this helps save the inverter if there's errant voltage that comes in from the panels, but thought it might help - then after the storms I turned the PV array back on. Ever since then one of the inputs keeps showing ~50W of input all throughout the night.

Anyone else seen this? Should I just turn off and on the inverter Windows-style restart? Should I turn on/off the PV disconnect during night time?

Let me know thoughts, thanks!
 
Hi, I have had a 6000xp for a couple months and certainly have seen this.

I have seen 50 watts of input shown going into the BATTERY while it was night time not the PV IN tho. It turns out this is because I was using grid and bypassing the battery. I imagine this occurs because the inverter needs to keep sync of the grid in order to quickly change to it. My thought is what if the battery is full? Does this still charge 50 watts to the full battery? This of course may not be what you are talking about as you specifically said PV input.

Second:
I was getting 500 watts total overnight from PV IN. about 50-55 watts/ hour. It was very strange. I had a PV line connected and it was laying on the ground right next to my grounding rod. About 4 inches away. Then it rained. Some how that line laying on the ground was intercepting AC thru the grounding rod and since I have a combiner box with diodes, it converted the AC to DC. This was not the house ground rod so I am a bit clueless.

That is as far as I know. I do not think that I am 100% correct on this but I figured I would chime in.
 
ScrotusGobbleBottom said:
Hi, I have had a 6000xp for a couple months and certainly have seen this.

Second:
I was getting 500 watts total overnight from PV IN. about 50-55 watts/ hour. It was very strange. I had a PV line connected and it was laying on the ground right next to my grounding rod. About 4 inches away. Then it rained. Some how that line laying on the ground was intercepting AC thru the grounding rod and since I have a combiner box with diodes, it converted the AC to DC. This was not the house ground rod so I am a bit clueless.

That is as far as I know. I do not think that I am 100% correct on this but I figured I would chime in.
Click to expand...

Thanks for sharing your experience, that's interesting and could be related to my issue. It actually stopped last night - went down to 0W around midnight but it went back up to ~30-50W at around 2AM.

One thing to note since you mentioned it on your side, is that this particular array is also coming from a combiner box. I don't think it's close to a grounding rod but it has been rainy, and the current cabling for it is above ground. The other array that is connecting directly to the inverter instead of through a combiner box isn't showing this errant voltage overnight.

Edit: Just checked, the voltage that the inverter is showing coming from that PV array is listed ~120V which would coincide with AC voltage! Definitely seems like AC getting converted to DC from somewhere.
 
The most interesting thing in my situation was the led signal lights in my combiner box. When I switched off all the circuits, all of the lights stated on except one. That means the voltage was coming in from the house instead of the panels. Must have been grounding itself near the rod. I really have no idea what happened.
 
The PV inputs are not fully isolated from the inverter circuit. This is also part of why they can't be grounded.

 
Thanks you two. I do think some of the panels could be leaky as they are my old array and have been rained on from a tin roof with some visible aberrations on the glass of some of the panels. Maybe coupled with the recent storm and low temperatures, could have caused a panel to malfunction. If I see wattage coming in tonight when it's dark again, I'll flip off the breaker in combiner box and see what the inverter shows at that point.
 
Alright, I flipped the combiner box breaker. Result is that the incoming 50W dropped to 0W immediately. Also, I noticed that there was a ground wire in the combiner box leading out that I have going to a ground rod.

Should I just ground at the panels for protection and ignore using this combiner box ground for anything? Does this further suggest a leaky panel or something else entirely - like errant voltage just feeding in via the ground line? What could cause 120V 0.4A to consistently go to ground?
 
girfold said:
Alright, I flipped the combiner box breaker. Result is that the incoming 50W dropped to 0W immediately. Also, I noticed that there was a ground wire in the combiner box leading out that I have going to a ground rod.

Should I just ground at the panels for protection and ignore using this combiner box ground for anything? Does this further suggest a leaky panel or something else entirely - like errant voltage just feeding in via the ground line? What could cause 120V 0.4A to consistently go to ground?
Click to expand...
I would ground the combiner box.
I got mine from watts247 and it has a lightning arrestor in it. Not sure if yours does but grounding it is necessary for the arrestor.

I wish I could help you more.
 
I checked this on my 6000XP. With the system running in bypass mode, I turned off the DC breakers on my PV lines and then checked the voltages on the PV terminals. The meter showed some AC voltage but it would bounce between 150V and 0V. The DC voltage actually initially showed close to the array voltage, but dropped to zero in a linear fashion over the timespan of a few minutes. I suppose that has something to do with the way the MPPT works. I'll have to try the lightbulb trick and see if there's any real power behind it, but I'm guessing not...

The behavior with the inverter running rather than in bypass mode was the same.
 
Side question: Is it useful at all to flip the PV disconnect during thunderstorms? Any good precautions I can make? I'm not grid tied at all, so no worries about voltage coming from a burst on the grid at least.

I'm in one of the top 10 States for thunderstorms, and though I've never had an issue at my current residence, I've had at least 2 instances with lightning strikes before. Back in my childhood home, the lightning travelled a phone line and fried a modem. Then a few years back at an apartment, had a lightning strike literally blow out a portion of the drywall where my Surface Pro was connected - its power supply was physically obliterated and burn marks all the way into the tablet.
 
AZ Solar Junkie said:
I checked this on my 6000XP. With the system running in bypass mode, I turned off the DC breakers on my PV lines and then checked the voltages on the PV terminals. The meter showed some AC voltage but it would bounce between 150V and 0V. The DC voltage actually initially showed close to the array voltage, but dropped to zero in a linear fashion over the timespan of a few minutes. I suppose that has something to do with the way the MPPT works. I'll have to try the lightbulb trick and see if there's any real power behind it, but I'm guessing not...

The behavior with the inverter running rather than in bypass mode was the same.
Click to expand...
Isn't this the same issue @Adam De Lay had with his 6500EXs where he would get shocked when touching the PV panels?
 
AZ Solar Junkie said:
What was your ground wire connected to? PV- or just the frames?
Click to expand...
The pv conductor was connected to an ungrounded (at the time) combiner box. The other end was empty and 3 inches away from a grounding rod. The panels frames and rack were grounded but not near the rod. They were however connected to the rod via 8awg bare copper.
 
ScrotusGobbleBottom said:
The pv conductor was connected to an ungrounded (at the time) combiner box. The other end was empty and 3 inches away from a grounding rod. The panels frames and rack were grounded but not near the rod. They were however connected to the rod via 8awg bare copper.
Click to expand...
Do you mean that you had a pv conductor connected to the box itself - not just to breakers inside it? That would certainly explain part of the picture - especially that you had trouble once you connected the combiner box to ground as well. Maybe I'm misinterpreting what you mean.

I know in the manual for the 6000XP, the only thing it says about grounding the array is "Do not ground negative PV lines, only solar panel frames".
 
AZ Solar Junkie said:
Do you mean that you had a pv conductor connected to the box itself - not just to breakers inside it? That would certainly explain part of the picture - especially that you had trouble once you connected the combiner box to ground as well. Maybe I'm misinterpreting what you mean.

I know in the manual for the 6000XP, the only thing it says about grounding the array is "Do not ground negative PV lines, only solar panel frames".
Click to expand...
PV line was, on one end, appropriate,y connected to the breaker in the combiner box. The other end had the MC4 connector laying on the ground 3 inches away from the grounding rod.
 
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