My First Grid Down Simulation - EG4 18Kpv - No Way to Maximize Use of AC-Coupled Solar Power?

[Luxpower_Gilbert]

I'll try these suggestions. I'm using the EG4 battery hub which is communicating with the inverter. I tried setting the AC Charge control back to SOC%, but the SOC% settings for AC Coupling stayed greyed out. I'll try the alternate settings method later.

Dm me you inverter sn # thank you.

 

[EG4_Jarrett]

I'll try these suggestions. I'm using the EG4 battery hub which is communicating with the inverter. I tried setting the AC Charge control back to SOC%, but the SOC% settings for AC Coupling stayed greyed out. I'll try the alternate settings method later.

Yes, Gilbert is 100% correct on this. if the discharge settings are set to be used via Voltage, then the state of charge values will remain greyed out. Switch it over to SOC, and set them to 98% start, 99% end and this should accomplish what you are wanting it to do. If you would like, I can do this on my end.

I apologize for just now seeing this. I should have gotten on this sooner.

 

[skoshorek]

@skoshorek just thinking out loud here- how difficult or easy would it be to switch the pv from the Delta inverter to the 18k pv . Is this an option?

I considered that during my planning stage, but with as little as I knew about solar at that point, I thought the AC Coupling would be much cleaner. It would also leave the MPPTs in the EG4 18Kpv open for potential solar additions. Also, the warranty on the roof mounted solar panels and Delta inverter, installed by Tesla for a previous owner, would be jeopardized if I made any big changes to that installation. Actually, I think for my system I made the right choice. It's working pretty well. I'm just looking to get the most I can out of the new equipment, and EG4 and Luxpower are responding pretty well to customer requests. They must feel like they're drinking from a firehose right now.

 

[skoshorek]

yes my system is not connected to the grid yet which is why it throttles so heavily after the battery is full. when i connect to the grid it will just export any excess production to the grid

my pleasure. you are right - there is a lot of help on this forum.

Just an update. I finally found where the detailed historical data can be accessed: through the web monitoring site. I've made screenshots of many of the charts and it's going to take some time for me to wrap my mind around all of it. I wish they would add a chart on the mobile app and LCD screen to show AC Coupled Power usage. The data is recorded, so it should be possible. That's my only solar power available, so I consider it as PV, but all charts on those monitoring versions show PV as zero, since I don't have panels directly attached to the MPPTs.

I have searched the data for frequencies of the inverters, and there are a couple of places where I can see the frequencies varying about 2-3 hz during operation. I'm not sure how to interpret this yet.

 

[skoshorek]

Yes, Gilbert is 100% correct on this. if the discharge settings are set to be used via Voltage, then the state of charge values will remain greyed out. Switch it over to SOC, and set them to 98% start, 99% end and this should accomplish what you are wanting it to do. If you would like, I can do this on my end.

I apologize for just now seeing this. I should have gotten on this sooner.

Yes, Gilbert is 100% correct on this. if the discharge settings are set to be used via Voltage, then the state of charge values will remain greyed out. Switch it over to SOC, and set them to 98% start, 99% end and this should accomplish what you are wanting it to do. If you would like, I can do this on my end.

I apologize for just now seeing this. I should have gotten on this sooner.

OK. I understand now that the SOC%-Voltage control setting for the Discharge will determine the settings possible for AC Couple.

But relative to using SOC% or Voltage for control, this is taking me back to where I started. I'm getting dizzy. On my Android app the Discharge SOC% On-grid Cut-Off setting can't be any higher than 90%. The app won't accept anything higher. This is why I switched to voltage control to begin with. The Discharge voltage control On-grid Cut-Off can be set as high as 56V, which leaves more power in my batteries while the grid is up. Until the software is updated to allow a higher SOC% Discharge On-grid Cut-Off I will want to stay with voltage control. I think you said earlier that EG4 is working to update this setting's upper limit.

I can still follow Gilbert's instructions to keep 5% gap between AC Couple (for off-grid only) START and END settings while using voltage control. I have them set at 54.2V and 57V respectively, which is approximately a 5% gap. Is 57V too high for the END setting? Will the batteries ever get that high? Maybe I should lower the END setting to 56V, and adjust the START to maintain 5% gap.

 

[1201]

I have searched the data for frequencies of the inverters, and there are a couple of places where I can see the frequencies varying about 2-3 hz during operation. I'm not sure how to interpret this yet.

It should be 60hz in normal operation. If it starts climbing that's the kpv asking the Delta to throttle output

 

[Luxpower_Gilbert]

OK. I understand now that the SOC%-Voltage control setting for the Discharge will determine the settings possible for AC Couple.

But relative to using SOC% or Voltage for control, this is taking me back to where I started. I'm getting dizzy. On my Android app the Discharge SOC% On-grid Cut-Off setting can't be any higher than 90%. The app won't accept anything higher. This is why I switched to voltage control to begin with. The Discharge voltage control On-grid Cut-Off can be set as high as 56V, which leaves more power in my batteries while the grid is up. Until the software is updated to allow a higher SOC% Discharge On-grid Cut-Off I will want to stay with voltage control. I think you said earlier that EG4 is working to update this setting's upper limit.

Max settings for On Grid cut off is 90%. This is always been… if you want to keep it at 100% 24/7 set the ac charge time to 00:00-23:59.

I can still follow Gilbert's instructions to keep 5% gap between AC Couple (for off-grid only) START and END settings while using voltage control. I have them set at 54.2V and 57V respectively, which is approximately a 5% gap. Is 57V too high for the END setting? Will the batteries ever get that high? Maybe I should lower the END setting to 56V, and adjust the START to maintain 5% gap.

When the battery is charging it will stay at 56-57 but once the battery starts to discharge the voltage will drop around 53-54v. Battery at high voltage will give more stress on the battery.
I recommend % over volt if using closed communication

 

[EG4_Jarrett]

I can still follow Gilbert's instructions to keep 5% gap between AC Couple (for off-grid only) START and END settings while using voltage control. I have them set at 54.2V and 57V respectively, which is approximately a 5% gap. Is 57V too high for the END setting? Will the batteries ever get that high? Maybe I should lower the END setting to 56V, and adjust the START to maintain 5% gap.

Follow Gilbert's advice. That way you can use Voltage and keep it higher than what SOC will allow.

I would say take a look at your batteries Charge settings. 56v is typically where it is set to end, so you would want to set the AC Couple END at that point. But the best thing to do would be take a voltage reading when the battery hits 100%, and set it to whatever that is, if you are looking for accuracy. Depending on the age of the battery, it could be higher than 56v or lower.

 

[Hedges]

Have you enabled Rule 21 on GT PV inverter?
It probably isn't default. Just the -SA voltage & frequency limits and time limits.
Rule 21 is what makes AC coupling smooth, with GT PV delivering exactly what load + charging require.

 

[Cmiller]

if UL1741SA, but it still can't do it quickly enough to respond to load changes.

I have 4x Victron Multiplus-2 3000/48 stacked for 120/240, then a Fronius 7.6 AC coupled (only 5.4kw PV hooked up to it for now) and it curtails absolutely perfectly! I am completely off-grid. The assistant you use for off-grid with the Victrons is different than the grid-tie assistant. Off-grid just uses frequency shift for curtailing and NOT communication! I do have communication set up for monitoring purposes, but it does not use communication to curtail! I have an electric dryer and have never had any issues with the system when the dryer kicks on and off! (That would be a 6,000w instant swing, BTW.)

Early on I had "tweaked" the frequency shift setpoints in the Victron PV Assistant, and did not realize, but had set the top end too low.

What would happen then was:
-batteries got full> frequency shifted slightly, but not enough> battery voltage climbed on up over a minute or 2 of time> battery BMSs shut down from overvoltage> Victron inverters shut down from battery overvoltage (Extra high spike of ~65-70V was caused from power flow after BMS shutdown!)> AC voltage climbed to ~270V> Fronius shut down from AC overvoltage>batteries and Victrons powered back up

All of this happened quickly enough that I only saw the AC overvoltage shutdown until I began to really watch what was happening. Then it all clicked..... I went back into those assistant settings, set them to factory default, and all my issues went away! Maybe I like playing with things too much....

 

[SparkyJJO]

Don't feel too bad. Factory default is rarely the best option, so we get used to tinkering to get it just right. When the factory default IS the best option, well, we're not used to that and it causes us issues. THEY CAN'T BE RIGHT! Oh... oops....

 

[sunshine_eggo]

I have 4x Victron Multiplus-2 3000/48 stacked for 120/240, then a Fronius 7.6 AC coupled (only 5.4kw PV hooked up to it for now) and it curtails absolutely perfectly! I am completely off-grid. The assistant you use for off-grid with the Victrons is different than the grid-tie assistant. Off-grid just uses frequency shift for curtailing and NOT communication! I do have communication set up for monitoring purposes, but it does not use communication to curtail! I have an electric dryer and have never had any issues with the system when the dryer kicks on and off! (That would be a 6,000w instant swing, BTW.)

Early on I had "tweaked" the frequency shift setpoints in the Victron PV Assistant, and did not realize, but had set the top end too low.

What would happen then was:
-batteries got full> frequency shifted slightly, but not enough> battery voltage climbed on up over a minute or 2 of time> battery BMSs shut down from overvoltage> Victron inverters shut down from battery overvoltage (Extra high spike of ~65-70V was caused from power flow after BMS shutdown!)> AC voltage climbed to ~270V> Fronius shut down from AC overvoltage>batteries and Victrons powered back up

All of this happened quickly enough that I only saw the AC overvoltage shutdown until I began to really watch what was happening. Then it all clicked..... I went back into those assistant settings, set them to factory default, and all my issues went away! Maybe I like playing with things too much....

Good to know! thanks!

Would love to see how you have things configured. I'd prefer to add a Fronius over another pair of Quattros.

 

[Cmiller]

Would love to see how you have things configured.

Are you referring to "flow of power", or settings? I could get you some screenshots of the settings, if that is what you are referring to. I will be adjusting settings a bit this weekend, as I am currently configured to be able to charge from a Honda EU2000 on a single inverter because my standby gen took a dump on me....

No, it is not fun using the 2,000w generator. Yes, it does take long to charge a significant amount. (10% gain in 4 hours of runtime......) lol

 

[sunshine_eggo]

Are you referring to "flow of power", or settings? I could get you some screenshots of the settings, if that is what you are referring to. I will be adjusting settings a bit this weekend, as I am currently configured to be able to charge from a Honda EU2000 on a single inverter because my standby gen took a dump on me....

No, it is not fun using the 2,000w generator. Yes, it does take long to charge a significant amount. (10% gain in 4 hours of runtime......) lol

Settings.

I'm using a Harbor Freight Predator 3500 120/240V model on only one quattro, so i feel your pain... about 1600W of charging. need to get the 2nd leg of the genny fed to the second quattro.

 

[Cmiller]

Settings.

I'll get some screenshots this weekend for you.

I'm using a Harbor Freight Predator 3500 120/240V model on only one quattro, so i feel your pain... about 1600W of charging. need to get the 2nd leg of the genny fed to the second quattro.

It does a man well to see someone else in a similar predicament.

Thankfully here in Ohio I'm seeing a forecast for some sunshine again this weekend, and some of this coming week! We shall have peace and quiet for a little while.