Did a full discharge test over the weekend and this happened.

Thanks for the screenshots...very valuable debug info!

Numbers all look reasonably within range--holding at 0 when in pass-thru mode makes it all the more strange/weird that it's tripping off.  I presume that the Xformer Volt error is usually an instantaneous trip as soon as the relay tries to switch on (i.e. "click-clack -> error")?

Only suspicious number is the Xformer Volt in the No Load test...that number should be ~32vAC, not 35.4vAC.  Unless the actual AC output is really 265vAC (= 240v / 32v = 7.5 * 35.4 = 265.5v) due to miscalibration?  Might want to measure the AC output sometime with a DMM.

4 minutes ago, Sid Genetry Solar said:

Numbers all look reasonably within range--holding at 0 when in pass-thru mode makes it all the more strange/weird that it's tripping off.  I presume that the Xformer Volt error is usually an instantaneous trip as soon as the relay tries to switch on (i.e. "click-clack -> error")?

Only suspicious number is the Xformer Volt in the No Load test...that number should be ~32vAC, not 35.4vAC.  Unless the actual AC output is really 265vAC (= 240v / 32v = 7.5 * 35.4 = 265.5v) due to miscalibration?  Might want to measure the AC output sometime with a DMM.

Of the around 20 or so times it has given me this error several of them for sure happened as soon as the inverter tried to switch over since it happened when I was watching it do so pretty much as soon as the relay clicked. 

Each time I upgrade the firmware I check the calibration against 3 different DMMs just to be sure since things get expensive fast if its too far out. After the very first firmware update I did from the initial shipped firmware 1.0r22 to 1.1r1 and it lost a bunch of the calibration settings, I make it a habit to check after every update before flipping the breaker back on.  I can check it again but I did check it a week ago and the voltage was reading about 241-242  I have found that I have to wait with calibration until the inverter is warmed back up since the displayed voltage won't read accurate till everything is at a constant temp but the actual output voltage as measured with a DMM doesn't change much.  The AC Line voltage from the grid is 246-248 every time I have ever tested it and I try to keep the inverter output close to that but usually a bit under.  I haven't had to adjust the AC output calibration since I upgraded to 1.1r1 as the actual measured output has stayed within 240-246v range this whole time.

What is really weird is that I was able to turn the AC input on and power up the inverter without it erroring in these tests but 2 nights ago it would shutdown with the error as soon as it booted up and said it was In-Sync on the screen and the relay would click (I assume it was trying to transfer and charge the battery bank).  The only difference between these two times was that the battery voltage was low enough <51.6v that the inverter attempted to transfer to the grid so it could charge the batteries 2 nights ago and charging was set to Auto. Last night the bank was at 52.3 which is above the ATS voltage setting with charging set to manual and it never tried to transfer as soon as it synced up to grid frequency after it was powered on.  Could it be that it is transferring to fast and it doesn't have enough time to get a stable reading?  That wouldn't explain why the error is happening when the bank goes low 51v when the inverter has been running all week just fine unless it is something to do with charging kicking in to fast after the transfer happens in this case as well.  

Yah, guess I didn't write that in the release notes...or they aren't in an easy-to-see location.  1.1r0+ was a major shift from all previous versions (both in how the settings are stored AND in communication protocol), so instead of copying the settings over, I replaced them with stock constants--which evidently didn't work in your case.  Shouldn't need to tweak those settings for quite some time I hope, so future updates shouldn't change it.

So bummed I didn't realize that optoisolators have a terrible temperature coefficient...that's what's causing the inaccurate readings and/or voltage shift on the output.  Switched to signal transformers on Rev. C...perfectly linear and with no temp coefficient.

I have a suspicion I know what the problem is...and I don't like it.  I believe you were one of the customers paying extra for express shipping...and while I thought we checked and redid the transformer spec on all of those units (gotta love the manufacturer, "oh, we did not know the voltage specification was +/-0.25v on the transformer"), it seems...that one slipped by.  Basically, I specified 8 turns on each low-voltage primary, but they did 8 on 1, and 9 on the others.  This is causing higher-than-expected output voltage for battery charge.  (We actually had them pull the first shipment of 25 inverters back from the shipping dock to fix the transformers after discovering this!)  Let me explain with mathematics:

Transformer spec for the current GS inverters should be 32v in, 240v out...clean ratio of 7.5.  But unfortunately it appears that your transformer is running closer to 35v in for 240v out...kinda right in line with what I recall measuring at Sean's place this past Dec. when we got them in.  This is not a critical problem, BUT it does cause several mathematical issues.

For one, the minimum DC input voltage for a true pure sine wave output at no load is...35.438 * sqrt(2) == 50.1v.  Not quite the 32 * sqrt(2) = 45.25v I'd designed for...but while it may be slightly annoying, it's not hurting anything.

Things get a tad trickier for AC input, and I believe also fully explains the "Xformer Volt" error you get when the battery is <51v.  If your grid is running ~248v in, we can calculate the transformer ratio at 240 / 35.438 = 6.77.  Thusly, 248v / 6.77 = 36.619vAC out from the transformer when the grid relay switches on.  And...36.619 * sqrt(2) == 51.78v MINIMUM DC OUTPUT IN CHARGE.  In other words, with AC Mains power, the inverter cannot regulate the battery charge less than 51.78v.  (Spec 7.5x ratio would output 33vAC @ 248v input = 46.76vDC minimum.)

So how does this cause the Xformer Volt error?  Well, if your batteries are < 51.78v, the instant the grid relay switches on, battery charge will start--despite the inverter doing nothing to regulate it.  While this won't be a problem (as the current will be relatively low), the inverter can see this "negative transformer current" despite charge not yet being engaged--and throws the Xformer Volt error, which I put in the code for just this purpose.

For 1.1r4, I can bump the error threshold up a tad for your usecase.  If the inverter's working fine otherwise, I can adjust the threshold.

That seems to make a lot more sense and fit with what I have been seeing.

Would this explain why the inverter seemed to struggle to start loads on occasion (starting the well pump) when the bank was low like <50Vdc and the flicker in the lights with the AC running?  Since a squareish wave is going to a bit harder to drive motors?

I can set the ATS setting at 52v (which would be around 30% SoC for the bank) and see if the error completely goes away when I let the bank run down and see if it transfers successfully.  This would maybe help verify if that fixes the issue.

If the transformer is slightly out of spec, is it possible to code in that setting change in the firmware specific to my my inverter's serial number so it doesn't affect your other inverters that are in the field presuming they are all running with the correct transformer specification?

I can obviously live with it as it is since it seems to be working properly other than that annoying issue.  Whenever the Rev C boards are available, and everything looks good or even when the 12 K is available (as I plan to purchase one eventually) is it possible to send the inverter back and have the transformer issue checked and corrected if possible and while it's in the shop pay to have the new Rev C board fitted?  I live in northern Wisconsin near Antigo so I might even be able to make a trip over to lower Michigan to save the shipping costs (and potential damage) if Sean is ok with it when that time comes.  Then if the 12K units are available at that time I would have one prepaid and waiting to be picked up at the same time.  I realize that this might be a year off depending on how things go.

11 minutes ago, kuhrd said:

Would this explain why the inverter seemed to struggle to start loads on occasion (starting the well pump) when the bank was low like <50Vdc and the flicker in the lights with the AC running?  Since a squareish wave is going to a bit harder to drive motors?

Yes, it would...as once the inverter runs out of headroom, it has to square-up the wave, but that only works so far.

Flicker in the lights would be voltage regulation...shouldn't be doing that with the latest firmware...??

12 minutes ago, kuhrd said:

I can set the ATS setting at 52v (which would be around 30% SoC for the bank) and see if the error completely goes away when I let the bank run down and see if it transfers successfully.  This would maybe help verify if that fixes the issue.

Sure, that'd be a good way to check.

13 minutes ago, kuhrd said:

If the transformer is slightly out of spec, is it possible to code in that setting change in the firmware specific to my my inverter's serial number so it doesn't affect your other inverters that are in the field presuming they are all running with the correct transformer specification?

Not easily at all, I'm afraid.

13 minutes ago, kuhrd said:

is it possible to send the inverter back and have the transformer issue checked and corrected if possible

It can most definitely be corrected...using a variac to test the transformer, remove the extra turn on each of the affected primaries, and then cut the excess wire off...then remove the enamel from the (new) ends of the transformer strands....followed by crimping new ends on.  Didn't say it was fun though 😉.

14 minutes ago, kuhrd said:

and while it's in the shop pay to have the new Rev C board fitted?

Umm...not easily.  About all you would notice with Rev. C would be things like improved AC input relays (dual-pole main relay, and auto AC input voltage selection.)  The basic design and functional concept of the Rev. C board is identical to Rev. A.1.  Yes, there's a few new sensors added (battery current [for FET overload, not necessarily calibrated], AC input current)...but that's about it.

Rev. C control board will require the GS mainboard / MOS boards (changed pinout of the cable), and a new specialized WiFi board (changed feedback circuitry due to the inability to source the CS5463 power meter chip, necessitating switching to a different chip altogether)--so basically everything except the transformer and chassis.  Speaking of which...drilling new holes for the GS mainboard in the chassis is NOT easy.  That stainless steel case is extremely difficult to cut or drill; I admire the laser cutter that the manufacturer has! 

11 minutes ago, Sid Genetry Solar said:

Yes, it would...as once the inverter runs out of headroom, it has to square-up the wave, but that only works so far.

Flicker in the lights would be voltage regulation...shouldn't be doing that with the latest firmware...??

Sure, that'd be a good way to check.

 

Not easily at all, I'm afraid.

 

It can most definitely be corrected...using a variac to test the transformer, remove the extra turn on each of the affected primaries, and then cut the excess wire off...then remove the enamel from the (new) ends of the transformer strands....followed by crimping new ends on.  Didn't say it was fun though 😉.

 

Umm...not easily.  About all you would notice with Rev. C would be things like improved AC input relays (dual-pole main relay, and auto AC input voltage selection.)  The basic design and functional concept of the Rev. C board is identical to Rev. A.1.  Yes, there's a few new sensors added (battery current [for FET overload, not necessarily calibrated], AC input current)...but that's about it.

Rev. C control board will require the GS mainboard / MOS boards (changed pinout of the cable), and a new specialized WiFi board (changed feedback circuitry due to the inability to source the CS5463 power meter chip, necessitating switching to a different chip altogether)--so basically everything except the transformer and chassis.  Speaking of which...drilling new holes for the GS mainboard in the chassis is NOT easy.  That stainless steel case is extremely difficult to cut or drill; I admire the laser cutter that the manufacturer has! 

The flicker is nowhere near what it was in 1.1r2 but it is still present at times when inductive loads are running like the well pump and AC but it is almost not noticeable at this point.  The flicker could even be caused by the load that is running and the regulation setting in 1.1r2 was just making it very noticeable.  It's most noticeable in the few LED lights that don't have a capacitor but is also visible in incandescent bulbs like the one in the fridge.  But like I said the flicker is hardly noticeable and only when the large loads are running.

The biggest reasons I wanted to move to the Rev. C board was the voltage fluctuations with the temperature and the newer input relay since it switches both L1 and L2.  As far as the transformer modification, I guess I can wait for the warranty period to expire and then take a crack at disconnecting the transformer and testing it with a variac to get the turns right.  It wouldn't be the first time I have made adjustments to the number of turns on a transformer.  The other, less sophisticated option is to go to 17S on the pack so the battery will never go below 51.7 in normal operation but I would need a different BMS at that point.

I plan to keep the 6K installed as a backup (maybe even a slave to the 12K) when the 12K is available.  I will definitely need to add 20-30KWh of battery storage before that happens heh.

Yes, it would fix both I guess.

Technically, swapping the pinout on the current PJ mainboard would suffice to use a Rev. C board (though it would need a new WiFi board).

Will say it's aluminum wire, so it's a bit harder to work with ;-).  Since you're at 48v, the easiest solution would just be to pull a couple turns off one of the primaries to get it down to 32v...only need to redo one of the ends that way.