3x EG4 6000XP uneven AC output

[Julius_sk]

Original system(May 2024) 2 EG4 6000XP with 10KW PV that were feeding 100amp main panel and they would hit 100% output and went into overload couple times. Since the original plan was to go with 3 I Added #3 inverter(two weeks ago). All the panels were switched out to larger system currently ~15KW producing up to 70KWh(yesterdays record for winter). 5 strings total: inverter #1 (2 strings); inverter #2 (2 strings); inverter #3(new one) 1 string. All three inverters are connected to 2 PowerPro 14.3KWh batteries+1 DIY kit 15KWh + 1 EG4 LL for a total of 50KWh. I was producing too much power so I mixed the batteries a bit. Switching out to 150KWh batteries withing two weeks, selling/reusing these in other setups. Also a Chargeverter is wired in or the backup, works wonderful with 120V 28A cheap genny.


Everything runs the house fine, charges the batteries without problems, discharges fine. App controls work fine besides the app crashing.

All inverters are wired in parallel feeding a 100amp subpanel. All AC 240 inputs and outputs are identical 6gauge THHN through 40A Breakers.

Now the funny, not so funny part. #1(master) and #2 will output about the same amount of power while the #3 will always be about 50% of the other two.
#1 inverter 60% load
#2 inverter 57% load
#3 inverter 30% load

Its always consistent. #3 is always 1/2 of what the #1 or #2 is showing as output. If I kill #1 or #2 separately, #3 is still at 50% of the #1 or #2 is putting out according to %. Even when sun is down and pulling from battery only.

Restarting, multiple times and cycling EPS output doesn't help. Any ideas please.

Again all outputs and inputs are in separate combiner panels. #1and#2 will ramp up together, #3 lags behind running @50% capacity of either 1 or 2

All battery cables are New EG4 PowerPro paralleling cables. All same connectors. It's consistent disrepancy between them. HELP please

 

[sunshine_eggo]

All inverters are wired in parallel feeding a 100amp subpanel. All AC 240 inputs and outputs are identical 6gauge THHN through 40A Breakers.

Same gauge, but are they they same length, or are #3 longer?

Now the funny, not so funny part. #1(master) and #2 will output about the same amount of power while the #3 will always be about 50% of the other two.
#1 inverter 60% load
#2 inverter 57% load
#3 inverter 30% load

Its always consistent. #3 is always 1/2 of what the #1 or #2 is showing as output. If I kill #1 or #2 separately, #3 is still at 50% of the #1 or #2 is putting out according to %. Even when sun is down and pulling from battery only.

Restarting, multiple times and cycling EPS output doesn't help. Any ideas please.

Again all outputs and inputs are in separate combiner panels. #1and#2 will ramp up together, #3 lags behind running @50% capacity of either 1 or 2

All battery cables are New EG4 PowerPro paralleling cables. All same connectors. It's consistent disrepancy between them. HELP please

Are the DC cables the same length, or in more general terms, is the resistance between each inverter and each battery the same?

 

[doox00]

my 3 are nearly identical. Latest firmware?

 

[Madcodger]

FWIW, my three 6000XPs have always behaved like that for AC output. We are fully off grid eith five Powerpro indoor batteries (70 KWH) and PV input doesn't seem to matter at all as I recall (the highest output inverter had no PV input for months). The battery cables are all the same length, but the length of cabling to the subpanel that combines the inverter outputs before they enter the main panel (I refer to it as the inverter combiner panel) does vary by a few feet due simply to the distance from each inverter to the combiner panel (they're just over a foot apart, each on top of a Powerpro battery). I'm running latest firmware, and updates to it haven't changed anything related to this.

Frankly, I've chalked it up to "it is what it is". We've never had a problem, and it all works fine. It's a curiosity and I'd love to know the true reason for it, but other than the modest difference in cable length from each inverter to the combiner panel, they're otherwise identical for me. But the outputs sure aren't.

 

[sunshine_eggo]

For phases in parallel, you want the resistance to be as identical as possible, AND you want to avoid excessive wire gauge as it amplifies the disparity.

The 6000XP recommends 8awg, and I wouldn't go over this unless the wire length/voltage drop was excessive, especially if paralleling multiple inverters.

 

[Quattrohead]

This is probably down to slight calibration variations between units. You could test this by swapping the units around and seeing if the over and under achievers move or stay in the same position thereby eliminating inverter or wiring.

 

[ksmithaz1]

Your PV is less on string 3? Why is this a problem?

 

[ksmithaz1]

Pretty surenit will bias output based on input. 100% on batteries, It should bias based on soc.

 

[Julius_sk]

All DC cables are same size, length, manufacturer, connectors. Using Powerpro busbar, all identical connections, so DC out of question. All stock EG4 2/0 full length. All batteries and all inverters are in parallel so DC nor solar doesn't affect the output. I have tested that by shutting off DC, PV, AC input.
There is only one difference - #3 input and output is #8 THHN vs #1+#2 originally wired with #6THHN too much work to rewire. If it was resistance of the wire, then the wire would get hot. We are talking 2KW output trough #6 or #8 is nothing. Inverter doesn't know wire size so when the house would try to pull AC through undersize wire it would just heat up wire in extreme case. It's the constant ratio of 50% of #1/#2 that bothers me, regardless the load. 20%/20% 10% 80%/80% 40% ETC

I guess i'll try factory reset, Firmware update and setup again from scratch and see what happens. Otherwise system is working beautifully.
Also got these "vent scoops" "deflectors" highly recommend if you have inverters side by side.

 

[TM48]

I was producing too much power so I mixed the batteries a bit

What does that mean exactly? Also what does the front panel displays indicate as far as load between each inverter?

 

[Brucey]

There is only one difference - #3 input and output is #8 THHN vs #1+#2 originally wired with #6THHN too much work to rewire. If it was resistance of the wire, then the wire would get hot. We are talking 2KW output trough #6 or #8 is nothing. Inverter doesn't know wire size so when the house would try to pull AC through undersize wire it would just heat up wire in extreme case. It's the constant ratio of 50% of #1/#2 that bothers me, regardless the load. 20%/20% 10% 80%/80% 40% ETC

It doesn't have to be enough resistance to be felt as heat. Its enough to throw off the load as you can see.

 

[Julius_sk]

It doesn't have to be enough resistance to be felt as heat. Its enough to throw off the load as you can see.

Well i would think that could be the case if the wire was undersized(more =resistance), Its oversized = less resistance. I understand "the path of least resistance"....... I guess i will try #6 since i have the wire anyway just for the hell of it.

 

[Julius_sk]

For phases in parallel, you want the resistance to be as identical as possible, AND you want to avoid excessive wire gauge as it amplifies the disparity.

The 6000XP recommends 8awg, and I wouldn't go over this unless the wire length/voltage drop was excessive, especially if paralleling multiple inverters.

Ok. I had a bunch of #6 and used it up. I mean next size up wire wouldn't hurt... I'll try to upsize #3 inverter to #6(from #8) and report back, perhaps it is just wire resistance, but 50% difference is massive, and i upsized, not downsized it. Will see

 

[Quattrohead]

Place your bets now, it is not the wire.

 

[TM48]

From your picture it looks like your parallel cabling is incorrect. There should be two comm cables between all three inverters. The last inverter should loop back to the first (master).

 

[Brucey]

Well i would think that could be the case if the wire was undersized(more =resistance), Its oversized = less resistance. I understand "the path of least resistance"....... I guess i will try #6 since i have the wire anyway just for the hell of it.

It's counterintuitive but oversized is not an advantage in this case. From Wiring Unlimited:

 

[SomethingAppropriate]

It's counterintuitive but oversized is not an advantage in this case. From Wiring Unlimited:

View attachment 274293

Damn, that is an interesting read.

 

[Brucey]

Damn, that is an interesting read.

https://www.victronenergy.com/upload/documents/The_Wiring_Unlimited_book/43562-Wiring_Unlimited-pdf-en.pdf

 

[Zapper77]

All DC cables are same size, length, manufacturer, connectors. Using Powerpro busbar, all identical connections, so DC out of question. All stock EG4 2/0 full length. All batteries and all inverters are in parallel so DC nor solar doesn't affect the output. I have tested that by shutting off DC, PV, AC input.
There is only one difference - #3 input and output is #8 THHN vs #1+#2 originally wired with #6THHN too much work to rewire. If it was resistance of the wire, then the wire would get hot. We are talking 2KW output trough #6 or #8 is nothing. Inverter doesn't know wire size so when the house would try to pull AC through undersize wire it would just heat up wire in extreme case. It's the constant ratio of 50% of #1/#2 that bothers me, regardless the load. 20%/20% 10% 80%/80% 40% ETC

I guess i'll try factory reset, Firmware update and setup again from scratch and see what happens. Otherwise system is working beautifully.
Also got these "vent scoops" "deflectors" highly recommend if you have inverters side by side.

View attachment 274196View attachment 274197View attachment 274198

are the 6000xp DIP switches correct?

 

[Zapper77]

Original system(May 2024) 2 EG4 6000XP with 10KW PV that were feeding 100amp main panel and they would hit 100% output and went into overload couple times. Since the original plan was to go with 3 I Added #3 inverter(two weeks ago). All the panels were switched out to larger system currently ~15KW producing up to 70KWh(yesterdays record for winter). 5 strings total: inverter #1 (2 strings); inverter #2 (2 strings); inverter #3(new one) 1 string. All three inverters are connected to 2 PowerPro 14.3KWh batteries+1 DIY kit 15KWh + 1 EG4 LL for a total of 50KWh. I was producing too much power so I mixed the batteries a bit. Switching out to 150KWh batteries withing two weeks, selling/reusing these in other setups. Also a Chargeverter is wired in or the backup, works wonderful with 120V 28A cheap genny.
View attachment 274120View attachment 274118View attachment 274121

Everything runs the house fine, charges the batteries without problems, discharges fine. App controls work fine besides the app crashing.

All inverters are wired in parallel feeding a 100amp subpanel. All AC 240 inputs and outputs are identical 6gauge THHN through 40A Breakers.

Now the funny, not so funny part. #1(master) and #2 will output about the same amount of power while the #3 will always be about 50% of the other two.
#1 inverter 60% load
#2 inverter 57% load
#3 inverter 30% load

Its always consistent. #3 is always 1/2 of what the #1 or #2 is showing as output. If I kill #1 or #2 separately, #3 is still at 50% of the #1 or #2 is putting out according to %. Even when sun is down and pulling from battery only.

Restarting, multiple times and cycling EPS output doesn't help. Any ideas please.

Again all outputs and inputs are in separate combiner panels. #1and#2 will ramp up together, #3 lags behind running @50% capacity of either 1 or 2

All battery cables are New EG4 PowerPro paralleling cables. All same connectors. It's consistent disrepancy between them. HELP please

Check your parallel cables.

 

[SomethingAppropriate]

https://www.victronenergy.com/upload/documents/The_Wiring_Unlimited_book/43562-Wiring_Unlimited-pdf-en.pdf

Thanks!! Diving in right now.

 

[Julius_sk]

From your picture it looks like your parallel cabling is incorrect. There should be two comm cables between all three inverters. The last inverter should loop back to the first (master).

Thank you, i totally missed that. Just looked at it in the picture again.... Looking at the manual, I am missing the return cable. That might be it, although system runs fine, settings propagate trough all three units evenly from any inverter(when changed on the app). Fingers crossed that will do. Will report back soon.

Thank you "BRUCEY" that is interesting indeed. Besides wasting money, I guess there is such a thing as "bigger isn't better". That #6 was a bitch to route. 8x8 Wireway minimum next time. I tried to be cheap on wireway

 

[Julius_sk]

From your picture it looks like your parallel cabling is incorrect. There should be two comm cables between all three inverters. The last inverter should loop back to the first (master).

Thank you, I messed that one up, I looked at the diagram when setting DIP's and last cable but forgot to run comms back to Master inverter

 

[TM48]

Thank you, I messed that one up, I looked at the diagram when setting DIP's and last cable but forgot to run comms back to Master inverter

I initially did the same which is why I noted it. Check to see if the "shared battery" parameter is on for all three inverters. It should be.

 

[Julius_sk]

I initially did the same which is why I noted it. Check to see if the "shared battery" parameter is on for all three inverters. It should be.

So I plugged in the comms cable, reboot everything = no change. Still #3 ~50% behind on higher loads. Complete reset and AC output wire swap is next over the weekend, when i can shut it all down.