EG4 18K Whole house setup problem after upgrading from Growatts.

[lotsofyoda]

So I upgraded to 3 x EG4 18k for my whole house (mostly) off-grid system.
And now I have some problems to solve that I can't wrap my head around.

We've been 100% off grid solar for 2 years.
I wanted to add grid-backup (not sell-back) to my setup, so my generator would run less during the winter (noise, propane use, etc)

Here is what I had previously and what it could do (my old system):

Equipment list:
6 x Growatt 5000 = 30 kw inverter power (in parallel) and autotransformers x 2
124 kwh lifepower4 battery bank (24 batteries total)
NO grid
20kw propane Cummins backup generator (max about 18kw possbilbe)
36kw Solar (96 panels)
Additional 3 Growatt 5000 inverters taking just my generator input.
Victron Shunt to start and stop my generator (the Growatts couldn't do it)
Solar Assistant for monitoring

Setup:
My 6 Growatt inverters are connected to
(1) House - to supply up to 30KW A/C power (worked well)
(2) Battery bank
(3) Solar
Their only job was to supply the house at all times (day and night using solar plus/minus battery bank) and keep the battery bank topped off for nigh use/bad weather use.

My additional 3 Growatt inverters:
- Only connected to Generator and battery bank (the generator 240V output would be used to charge the battery bank) and was hooked up into grid input on the inverters. So it inverts the 240V input from the generator and acts just as a battery charger.
- Only one way from Genertor to Battery.
- no solar, no house connections.
- These 3 (total 15kw capacity) have only one purpose: charge the batteries when SOC < 15%
- Fired by the Victron shunt which reads the BMS of my batteries and turns on/off the generator.

This system worked well. Extremely well.
So, why change it?
Some limitations:
- no grid backup (and I want to use my generator less)
- Some growatts were breaking and I had to replace a few over the 2 years
- EG4 18K better/newer tech supposedly and can do it ALL??
- upgrade program to get to the EG4 18Ks.
- Growatts not able to directly manage generator, but had to rely on Victron shunt to do this.
- 9 x 70W per hour power consumption for all the Growatts = 630 W per hour just to keep them going. That's 15kw per 24 hours just to have the 9 inverters on the wall.

So, I took down all the 9 Growatts and replaced them with 3 x EG4 18k.

New setup:
- 3 x EG4 18k
- Same battery bank 124kwh
- Same solar panels (new arrangement in how they get to the inverters)
- Same generator.
- Grid backup (10kw limit due to transformer on my property)

The new setup is really nice looking and simpler all into each of the 3 inverters now:
- Generator wired to Gen input
- Grid wired to Grid input
- Solar input
- Battery bank

Order of operation should be simple and what I'm looking for: (but I can't get it to work like this):
(1) Use solar to charge batteries and power load (works)
(2) In absence of solar, use batteries to power loads (works)

What should work, but does NOT:
(3) When SOC of battery drops below 20%, use backup grid (10kw) to charge battery/help with load
(4) When grid not available use GEN instead (18kw) to charge battery/help with load

This works if the total Load is less than 10kw.
As soon as load exceeds 10KW (max of grid), my breakers flip on the grid side. The inverters try to draw more than 10K from grid.
It's like the inverter tries to get the whole load from grid.

What I would expect:
Load is 15kw. Inverter draws 10kw from grid and 5 kw from battery bank.
Load is 9kw. Inverter draws 10 kw from grid and supplies 1 kw to charge bank
Load is 4kw. Inverter draws 10 kw from grid and supplies 6 kw to charge bank.
Load is 25kw. Inverter draws 10 kw from grid and supplies zero to charge bank, draws the shortfall of 15kw from bank.

Under Application Settings, I have the max AC Input Power KW set to 3 (each inverter) so below the 10kw max I could draw. But it draws more than this limit.
I would expect this number to be the grand TOTAL that my inverter could ever draw from grid all inclusive.

I have AC charge enabled. and AC charge power is also set to 3 KW. So max battery charging should be limited to 9 kw for the total of 3 inverters.

Interestingly, below 10 kw total load, the inverters behave as expected. Meaning that if the load is 8 kw, then only 1 kw is used to charge batteries. If load is 3kw, then 6 kw is used to charge batteries. BUT as soon as load is 12k, then the inverters try to draw all of it from grid and none from battery bank. Not sure what to do.

So tech support suggested that the AC charge power for AC charge of battery bank is in ADDITION to the max AC Input Power KW set under the Application settings.
They suggested that I need to upgrade my grid to 25kw. But I will have the same problem as soon as my load goes to 26kw. It'll overload my grid and flip grid breaker. I would assume the same would also happen if grid was off and gen used instead. I'd hit a had top of maybe 18Kw for my generator. The answer here cannot be to get a 36kw grid connection and 36kw generator to match my max inverter output of 36kw.

Any help would be appreciated.

One solution I see is buying a 4th 18k inverter that just handles my grid and generator connection like my previous 3 Growatt inverters did.

So essentially:
Keep my 3 x 18kw EG4 and only connect them to Solar, battery and house.
They just supply the load, charge/discharge the bank using solar.

A 4th EG4 18k is ONLY there for handling my grid and generator inputs. It's only connected to Grid, gen and battery bank.
It does not communicated with the house, solar or the other inverters. (like my old setup above).
It reads SOC of battery bank. If SOC drops, it turns on grid just to "charge my battery" in the background. or fires Gen if grid is down to do the same.
The other 3 EG4s are none the wiser. They don't know anything and keep supplying the house with power no matter what, up to 36kw.

This setup worked well for me in the past. I'm tempted to repeat it, but with 4 x EG4 18k instead of 9 Growatt 5000 inverters.

Wow, long post.

I'm hoping there are just some settings I can tweak that will do this job for me with the existing 3 x EG4 18k that I already own instead of buying another one and adding it. But I will if there's no way around it.

In case you're curious why I would ever need that much load at all? Yes, I've loaded routinely in the teens and quite a bit in the 20s for charging my electric car, running all of our appliances and shop, etc.

Thanks,
Christian.

 

[rogerheflin]

Please detail all of your settings. If you have the inverter set into off-grid mode then the load either comes all from the batteries/solar OR all from the grid. In off-grid mode the inverter only runs when you are on the battery, otherwise you WILL export some power when large loads switch on.

 

[TM48]

That is a tiny transformer. Any chance you can get the power company to upgrade it? As an example the xformer that feeds my house is 50KW.

 

[Quattrohead]

It definitely seems to be a settings issue, you need to get with one of the EG4 techs not signature solar techs.
Let me see if I can get someone to respond to you.

 

[1201]

maybe the inverter cannot support the loads when the soc is that low?

you have a huge battery bank but is there a software setting that prevents the 18kpv from using the battery at all below a certain SOC?

it could be a protection mechanism or something. does it work if soc is say 50%?

 

[EG4TechSolutionsTeam]

Could you export your settings and post them in thread? Also, feel free to DM me the serial number of the inverter and I can take a look at the data/settings.

 

[B-Mod]

Any reason not to use chargeverters for your charging?

 

[DIYrich]

Any reason not to use chargeverters for your charging?

This ^^^ But, if you have growatts available, why not hook one up to the grid to directly charge the battery?

 

[kw5kw]

First... what are you running that you need three 18kpv's?
I have:
2000 sq ft home
2000 sq ft detached garage (inverter lives in here)
500 sq ft shop which houses a water softener (must be protected from freezing)
I am running on only one.
And, I am running four mini-split heat pumps usually two at the same time.
Two refrigerators, one freezer.
Standard washer/dryers about 7 years old.
Hot tub
Two infrared heaters (one in shop (water softener) , one in garage office (much less draw than other heaters)).
Two water heaters.
Plus all the usual kitchen appliances and accessories. ie: coffee maker, microwave, hot pot, toaster oven, air frier, etc.
Three televisions, internet and computers, printers, etc.
I keep my RV plugged in 24/7/365 (unless were using it elsewhere)
Not to mention my ham radio(s)!
And, my shop has welder, saws, drill press etc.

I've only hit 10kW once in the three months it has been in service.

 

[TM48]

Are the 18's switching to pass thru when the 9 kw limit is reached there by pulling what ever the load is? Which of course is greater than 10KW. Your grid supply is only about 40 amps, less than what one inverter can supply while inverting.

 

[rogerheflin]

If he has the 18kpv set to "off-grid" mode then the 18kpv will not boost the grid power (because that will export sometimes) with batteries and will either pull all of the load from the batteries or pull all of the load from the Grid and that sounds like what may be happening. In "off-grid" mode it just acts as a transfer switch and uses grid or inverter+batteries for the load, but never both.

 

[42OhmsPA]

First... what are you running that you need three 18kpv's?
I have:
2000 sq ft home
2000 sq ft detached garage (inverter lives in here)
500 sq ft shop which houses a water softener (must be protected from freezing)
I am running on only one.
And, I am running four mini-split heat pumps usually two at the same time.
Two refrigerators, one freezer.
Standard washer/dryers about 7 years old.
Hot tub
Two infrared heaters (one in shop (water softener) , one in garage office (much less draw than other heaters)).
Two water heaters.
Plus all the usual kitchen appliances and accessories. ie: coffee maker, microwave, hot pot, toaster oven, air frier, etc.
Three televisions, internet and computers, printers, etc.
I keep my RV plugged in 24/7/365 (unless were using it elsewhere)
Not to mention my ham radio(s)!
And, my shop has welder, saws, drill press etc.

I've only hit 10kW once in the three months it has been in service.

Maybe you missed the OPs response.

In case you're curious why I would ever need that much load at all? Yes, I've loaded routinely in the teens and quite a bit in the 20s for charging my electric car, running all of our appliances and shop, etc.

...

I can easily exceed 10Kw on a daily basis. This is charging the car at 10 amps and running the dryer after work.

Any reason not to use chargeverters for your charging?

Agreed, but wouldn't that kind of defeat the purpose of 'upgrading' to the 12KWs?

 

[lotsofyoda]

Could you export your settings and post them in thread? Also, feel free to DM me the serial number of the inverter and I can take a look at the data/settings.

Here are my current settings. Thanks for all the feedback. I think some of the responses have nailed my most likely problem. It's completely trying to use grid or battery. But not both.

 

[lotsofyoda]

Please detail all of your settings. If you have the inverter set into off-grid mode then the load either comes all from the batteries/solar OR all from the grid. In off-grid mode the inverter only runs when you are on the battery, otherwise you WILL export some power when large loads switch on

 

[lotsofyoda]

Any reason not to use chargeverters for your charging?

No. Just buying 3 more of them (5kw each) to handle my grid (10kw) and generator input.
Would increase my "inverters" on the wall to 6 again. But this would potentially solve my problem and get me back close to my original setup I had with 6 Growatts + 3 Growatts.

 

[lotsofyoda]

This ^^^ But, if you have growatts available, why not hook one up to the grid to directly charge the battery?

Yes, I could do that again. I could use 2 for 10kw total. But it puts my total inverter count up to 5 on the wall. But yes, this would fix it. In a round about way as I had originally, which worked well. But I upgraded to these new 18kw because they were supposed to be much superior and handle everything in one. And cutting back on 70W per hour per inverter in electricity.

 

[lotsofyoda]

First... what are you running that you need three 18kpv's?
I have:
2000 sq ft home
2000 sq ft detached garage (inverter lives in here)
500 sq ft shop which houses a water softener (must be protected from freezing)
I am running on only one.
And, I am running four mini-split heat pumps usually two at the same time.
Two refrigerators, one freezer.
Standard washer/dryers about 7 years old.
Hot tub
Two infrared heaters (one in shop (water softener) , one in garage office (much less draw than other heaters)).
Two water heaters.
Plus all the usual kitchen appliances and accessories. ie: coffee maker, microwave, hot pot, toaster oven, air frier, etc.
Three televisions, internet and computers, printers, etc.
I keep my RV plugged in 24/7/365 (unless were using it elsewhere)
Not to mention my ham radio(s)!
And, my shop has welder, saws, drill press etc.

I've only hit 10kW once in the three months it has been in service.

Yeah, I have a 6000 sqft home. Commercial kitchen to make chocolate (can use 15kw at any one time just by itself - I make bean to bar artisan chocolate commercially) and an electric car. I have 2 mother-in-law suites included in my 6000 feet, each with full kitchen and laundry and 2 of my kids live there currently, cooking, etc. Because I built a huge solar system and battery bank, I went all in on electric. All appliances, heating, cooling (mini-splits), etc. So I have topped 28kw before and even tripped the 30kw once during the 2 years, causing a system shutdown. So I actually wanted to go up past 30kw on inverting power (and 3 x 18kw will do that = 36kw).
I'm essentially an electricity pig with all that I have. But I'm equally proud doing all that with solar and generating almost all of if other than the worst 3 months of the year during overcast winter days. Then, I'm also waaayyyy more careful about running extra electric and have some supplemental heat, etc.

 

[lotsofyoda]

If he has the 18kpv set to "off-grid" mode then the 18kpv will not boost the grid power (because that will export sometimes) with batteries and will either pull all of the load from the batteries or pull all of the load from the Grid and that sounds like what may be happening. In "off-grid" mode it just acts as a transfer switch and uses grid or inverter+batteries for the load, but never both.

This seems to be the problem exactly. Question is, can I just take it out of off-grid mode? Or do I need to tweak a bunch of other settings also to make this all work?

 

[fnnwizard]

I haven't read your post for 100% understanding, but looking at your settings, I can see issues right away.

So really quick, For
A=you need to limit the grid power to 10kW.

B= Is global powwer setting and should be equal to greater than AC Charge. It is setr at 12Ax52.1V=only 625W = You solar is only charging it at 625W. Whats SOC to start set at?

C= Y R U force discharging?

Sorry for short ??? and answer. be back later tonight to have indepth look.

 

[lotsofyoda]

OK. So taking it out of Off-grid mode and changing a couple of other settings, It's now charging my batteries at least properly.
I set my max draw to 9kw and max battery charge to 9kw. Currently my load is 6kw and my battery is charging for the rest of the 3kw.
I'll now turn on and run my loads past 10kw and see what happens.

 

[lotsofyoda]

I haven't read your post for 100% understanding, but looking at your settings, I can see issues right away.

So really quick, For
A=you need to limit the grid power to 10kW.

B= Is global powwer setting and should be equal to greater than AC Charge. It is setr at 12Ax52.1V=only 625W = You solar is only charging it at 625W. Whats SOC to start set at?

C= Y R U force discharging?

Sorry for short ??? and answer. be back later tonight to have indepth look.View attachment 253118
View attachment 253119
View attachment 253120

Thank you!!
For some reason, these settings didn't load when I took the PDF screenshot.
Here is a new one. And yes, I corrected your items you pointed out already.

Here is another new copy of my settings.

 

[lotsofyoda]

Another update.
So with changing the setting to 9 kw max AC input power and 9 kw as max AC charge power and disabling Forced discharge.
When I pushed my total system load to past 10KW, my solar assistant showed my load peaking at 13.3 kw and it drew it all from GRID. See attached. Technically, that should not be possible with both of those settings at 9 kw. Not sure why it's still doing that.

Added a second one. As long as my load is less than the set 9kw, it handles the split of load and battery charging just fine.
But if load exceeds the 9kw, it still continues to use grid without battery contribution.

 

[1201]

Another update.
So with changing the setting to 9 kw max AC input power and 9 kw as max AC charge power and disabling Forced discharge.
When I pushed my total system load to past 10KW, my solar assistant showed my load peaking at 13.3 kw and it drew it all from GRID. See attached. Technically, that should not be possible with both of those settings at 9 kw. Not sure why it's still doing that.

Was this instantaneous or sustained?

What is the current battery soc?

 

[lotsofyoda]

This seems to be the problem exactly. Question is, can I just take it out of off-grid mode? Or do I need to tweak a bunch of other settings also to make this all work?

Turns out just taking it out of off-grid mode didn't help. Still have the same issue.

 

[fnnwizard]

Another update.
So with changing the setting to 9 kw max AC input power and 9 kw as max AC charge power and disabling Forced discharge.
When I pushed my total system load to past 10KW, my solar assistant showed my load peaking at 13.3 kw and it drew it all from GRID. See attached. Technically, that should not be possible with both of those settings at 9 kw. Not sure why it's still doing that.

Added a second one. As long as my load is less than the set 9kw, it handles the split of load and battery charging just fine.
But if load exceeds the 9kw, it still continues to use grid without battery contribution.

I just tested this out and can verify you found a limitation of the 18 and it behaves exactly as you have described. I'm basically regurgitating below what you wrote already, but hopefully made it easy for those following to understand.

As for tech support saying ac power is in addition to grid power, it is not, since 18 derates power to ac charge as you also described in detail.

When setting (in your case) max grid power to 9kW, then AC charge power to 9Kw...
As long as regular loads are less than 9kW, AC charge will send energy towards Batts and max grid limitation setting is respected.

As loads increase, AC batt charging will get derated until batt charging goes to zero, but grid will be tasked to keep providing power all non ac charge over 9Kw.

Example:
Loads 5kW, 4kW goes to AC charge.
Loads 7kW, 2kW goes to AC charge
Loads 9kW, zero goes to AC charge
Loads 11kW, 18 will try to pull 11kW from grid (and potentially trip breaker.)

Grid power cannot be supplemented from Batt.

There is no solution for you, at least at this time, sorry.

If you want to post your data logs, perhaps we can figure out a way to work around the limitation, or minimize its effect.

Oh, in your settings, I would set your V to 55.2V - 56.8V depending on what is at the battery terminals. 59.2V is too high and more than likely drive BMS to disconnect. If batts are allowed to reach lower V in that setting first, 18 will put batts in standby, even doing a small discharge but BMS will always be ready to go.