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Flickering lights on new EX-6500 system

I've checked the AC Inputs and Outputs with a multimeter and it all looks pretty normal (I think) Running 122v steady AC IN and 119 AC OUT. AC IN shows about 0.3v N to G. AC OUT is about 2.2V N to G. I don't currently have access to a scope but could borrow one. How would I test with that and what would I look for?
I used a scope on mine when the lights would flicker. Waveform perfect really, frequency held steady. Voltage would fluctuate between 112V and 126V. I wouldn't purchase a scope for just this purpose, borrow maybe but really all it will show is the voltage regulation problem.

Went thru the whole process of checking circuits and even running some new ones. Flicker remained, actually seemed to get worse.

Sig Solar sent me the needed USB to serial cable free of charge after sending Ben a DM. I finally updated the firmware last night to the latest mobile firmware and the flicker has been absent. I used the mobile firmware update because I do have the bonding screw in one inverter.

You state the firmware is latest, I'd make certain it is by comparing the inverter display to the current download for the firmware. Adam put this in resources also. https://diysolarforum.com/resources/eg4-6500-firmware-changelog.319/

As for the lights being on when turned off, there most likely is a problem with your neutral/ground. Power is not coming thru the switch, the only path would be neutral to ground. Three things to measure with your multimeter. L to N, L to G and N to G. The L to N voltage added to N to G voltage should equal L to G voltage. If not, you have a problem. I do see you have a ground loop between inverters. You should only have one EGC run to each inverter or daisy chain them back to the main panel. I purposely kept the EGC from PV from my AC ground busbars and ran it back to the main or subpanel busbar which is close to the ground electrode.

This is how I wired mine, note the EGC runs right back to the main panel. https://diysolarforum.com/threads/neutral-ground-bonding.61081/post-760902
 
It is required to ground metal plumbing, but it is no longer considered sufficient for establishing earth ground.
Thank you for the links. I appreciate it and all the comments folks are making.

I would like to avoid this discussion diverting into the Code Compliance arena though. My comment to Markus was just to show that there is a path to ground for surges from the PV system.

I do feel that there is a grounding issue with this system, either in the solar system itself or in the house wiring. But I cannot find it. The DC system is extremely simple. There are no DC loads. There are no groundable components in the PV panels. (No racks, no frames, no metal boxes) The only ground connection is from the surge/lightning protector in the Combiner boxes to earth ground.
I am still unclear on the status of the N/G bond in the inverters. SS says my models are after they removed the bonding screw, and that my latest firmware (79.63) also disconnects this bond, but I would like to verify this. Where is the screw located, and is there a test I can run to test the N/G bond status of the inverters?
 
I used a scope on mine when the lights would flicker. Waveform perfect really, frequency held steady. Voltage would fluctuate between 112V and 126V. I wouldn't purchase a scope for just this purpose, borrow maybe but really all it will show is the voltage regulation problem.

Went thru the whole process of checking circuits and even running some new ones. Flicker remained, actually seemed to get worse.

Sig Solar sent me the needed USB to serial cable free of charge after sending Ben a DM. I finally updated the firmware last night to the latest mobile firmware and the flicker has been absent. I used the mobile firmware update because I do have the bonding screw in one inverter.

You state the firmware is latest, I'd make certain it is by comparing the inverter display to the current download for the firmware. Adam put this in resources also. https://diysolarforum.com/resources/eg4-6500-firmware-changelog.319/

As for the lights being on when turned off, there most likely is a problem with your neutral/ground. Power is not coming thru the switch, the only path would be neutral to ground. Three things to measure with your multimeter. L to N, L to G and N to G. The L to N voltage added to N to G voltage should equal L to G voltage. If not, you have a problem. I do see you have a ground loop between inverters. You should only have one EGC run to each inverter or daisy chain them back to the main panel. I purposely kept the EGC from PV from my AC ground busbars and ran it back to the main or subpanel busbar which is close to the ground electrode.

This is how I wired mine, note the EGC runs right back to the main panel. https://diysolarforum.com/threads/neutral-ground-bonding.61081/post-760902
ZWY, thanks for all that. I like the way your system is wired. It would make it much easier if I had a switch box that allowed me to choose direct powering the loads from grid or from the inverters, but my system was originally installed almost 20 years ago and that wasn't how it was done then. It would take a bunch of work to re-do it now I think.
Firmware is 79.63, so that should be good.
I notice you have one inverter bonded and the other not. I have seen some system do this and others with no bonds. Why a bond in one inverter, if there is already one in the Service Main box?
 
I am still unclear on the status of the N/G bond in the inverters. SS says my models are after they removed the bonding screw, and that my latest firmware (79.63) also disconnects this bond, but I would like to verify this. Where is the screw located, and is there a test I can run to test the N/G bond status of the inverters?

With the inverter disconnected and everything off, check for continuity between neutral and ground on the output side. Report back.
It's a lot easier than opening the inverter.
 
ZWY, thanks for all that. I like the way your system is wired. It would make it much easier if I had a switch box that allowed me to choose direct powering the loads from grid or from the inverters, but my system was originally installed almost 20 years ago and that wasn't how it was done then. It would take a bunch of work to re-do it now I think.
Firmware is 79.63, so that should be good.
I notice you have one inverter bonded and the other not. I have seen some system do this and others with no bonds. Why a bond in one inverter, if there is already one in the Service Main box?
Some use the common neutral method where the system is relying on the N-G bond at the main service panel. Others regard the inverter as source and all electrons return to source. I'm in the latter camp, I prefer bonding at the inverter and I'm using a 3PDT to classify as a SDS (seperately derived system).

I run my system with AC input disconnected, however the main panel neutral would still be connected, however the internal transfer switch of the 6500EX will switch the neutral, thus the N-G bond in the main panel would not function for ground fault protection.

The newer firmware for stationary application on the 6500EX relies on the common neutral method for N-G bond and does not switch the neutral in the internal transfer switch. This is why I'm using the mobile firmware instead of the stationary. I just don't see the advantage of pulling the bonding screw and relying on the main panel N-G bond.

As for why only 1 bonding screw? If you look in the archives for LV6548 and EG4 6500EX bonding, you will find many threads, some 30 pages long, as we hashed out N-G bonding before the latest firmware updates and directive by Signature Solar regarding bonding plus the video they released. I already had my system in place and wired and stuck with my original plan.

I did experiment with both bonding screws in place to determine if any detectable objectionable current would be present between the 2 inverters with 2 bonding screws in place (again, look in the archives for discussions on objectionable current and parallel paths). I actually never measured any current or even voltage potential between the 2 inverters with inverters operating and unequal loads in place on each leg. But I did have the flickering light problem and decided to remove one bonding screw as Filter Guy advocated in the many discussions concerning objectionable current and parallel paths. It didn't fix the flicker. So I just left the remaining bonding screw in place. I still consider the inverters as source and all current will return to the source.

I do question the multiple EGC's you have run. This can create a number of parallel paths if you have any leakage from N to G in your system.

You need to ensure N-G bond at only one location and eliminate any possibility of ground loops like the multiple EGC's between the inverters.

As has been mentioned, the best method to determine if your inverter has a bonding screw that is possibly dynamic is to measure continuity between N and G on the inverter output with system AC input and output disconnected from the inverter and inverter turned off. If there is not continuity, then N-G bonding screw is not present.
 
Had that same issue. To fix it we put all the lights, water heater, and room and living/family plugs on one phase of the sub panel. Kitchen plugs, bathroom plugs, washer, gas dryer, microwave, gas stove on the other. We also put a soft start on the AC to control the ramp up to not trip the system when everything is turned on at the same time. Beyond that you can't do much about those 2 pole circuits.

Each inverter, although tied in parallel, provide the requested power to the leg of the sub panel they are connected too. Power fluctuations from fridges, freezers, washers, dryers, toasters, blow dryers, vacuums, to name a few, will cause light flickering. You can swap out your bulbs, which help, but we found you have to put all of your lights on one phase and then add additional circuits that doesn't produce the flickering problem. Everything else needs to be on the other phase.

Again 2 pole breakers use both phases and can't do much with them except add soft starts and/or replacing with newer more efficient replacements. Hope this helps.
 
Update on my flickering light problem. With the mobile firmware installed, there was some flicker last night. Next step will probably be to remove the remaining bonding screw and update firmware to the latest stationary firmware. Flicker is very intermittent, last night was with 1800W of load, if increased to 3000W the flicker would go away. This is a voltage regulation problem.

If the problem persists after that, I will be pushing towards replacement inverters.
 
Had that same issue. To fix it we put all the lights, water heater, and room and living/family plugs on one phase of the sub panel. Kitchen plugs, bathroom plugs, washer, gas dryer, microwave, gas stove on the other. We also put a soft start on the AC to control the ramp up to not trip the system when everything is turned on at the same time. Beyond that you can't do much about those 2 pole circuits.

Each inverter, although tied in parallel, provide the requested power to the leg of the sub panel they are connected too. Power fluctuations from fridges, freezers, washers, dryers, toasters, blow dryers, vacuums, to name a few, will cause light flickering. You can swap out your bulbs, which help, but we found you have to put all of your lights on one phase and then add additional circuits that doesn't produce the flickering problem. Everything else needs to be on the other phase.

Again 2 pole breakers use both phases and can't do much with them except add soft starts and/or replacing with newer more efficient replacements. Hope this helps.
Thanks ChrisB. This is an issue I have been pondering but haven't acted on yet. I see info about interference from one circuit to another but haven't seen much specific about how best to organize my breaker box for best effect. Yours is the first specific guidance I've seen. So it looks like you are putting all lights on one leg, then the large, intermittent loads on the other, right? I need to look and see how many breakers I would need to move to accomplish that.
I'm also adding a 4th array, about 3250 more watts, which comes close to doubling my PV. I'm already under utilizing the PV (refilling my battery stack by mid-day on a good day). So I need to figure out what else to move to the sub panel. I'm assuming A/C (5 ton unit), Heat (electric strips), and hot water (2 40 gallon electric heaters) are all too big for my array. Everything else seems fair game.
 
I’m just bringing online an off grid system. I have 2 inverters and 2 more to flash with the most current firmware.

The only flickering so far is when the contractor was running his airless paint spraying. This flickering can also be seen when on grid as the pump draws high current when pumping as it is constantly starting and stopping with a huge inrush each time.
 
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