Grid-Tie Solar (kinda) with Growatt 5000 and Jakiper Batteries

[DC1986]

Hello,

I believe a little background is necessary for someone to possibly help me with my Jakiper battery system. Here it goes:

1) I purchased a grid-tied solar system last year. 30 panels = 13,500 watts (system has a Solar Edge inverter at the array and works well) Mostly I'm producing enough solar power to power my house. BUT, I want to add a battery wall to run during the night when solar production is off.

2) I installed a SECOND 200 amp electrical panel in my house (right next to my existing grid power panel) This 2nd electrical panel will ONLY be used as a load panel to items in my house (i.e. hot water heater, microwave, refridge, well pump etc.) up to the point my batteries will be able to run them through the night when solar production is off. Again, this panel will NOT return any electricity back to the grid.

3) I then installed (2) Growatt SPF 5000 EU power inverters/charge controllers and a SolarEdge auto transformer. (Yes, I bought the Growatt's from Signature Solar and the N is not bonded to the G) So far all is going well.

4) Supply Chain is getting crazy and I find getting LiFePO4 batteries are getting hard to come by. I see these Jakiper batteries that look pretty good. Will Prowse has reviewed them. So, I punched the ticket and bought some. They are Jakiper: Model JK48V100, Rated Voltage 51.2V, 100 Ah, with a BMS screen and controller (rack mountable) I purchased 3 batteries so roughly 15kwh of power.
Website says BMS communication, BUT, these are the ones WITHOUT BMS communication to the Growatt SPF 5000 EU versions. DAMM!!! I didn't realize this.

5) I do understand that the Growatts can still be used by voltage settings in the Growatts. (Again, DAMM, I wish the BMS in the Jakiper could communicate with the Growatts)

6) The Growatts are programmed in Group/Program #49 to accept grid power from 10 am to 3 pm (setting would be 1015). As for the Growatts use 24 hour time for programming.

7) There isn't any solar panels input connected to my Growatts. AC power input only.

My Goal: My goal is to capture as much solar power during the peak hours of 10 am to 3 pm and fill my batteries during this time. This power will come from my original grid-tied house electrical panel via (2) 2P40 amp breakers one to each of the 2 Growatts. During this time my panels are producing more than my house requires and thus, sending excess power back to the grid (of which they only pay 1/10th rate for my production). I want this excess power to go into my batteries and use that battery power at night. Hope this all make sense. (sorry for the "Gone with the Wind" length of explanation...)

Problem: Since I don't have BMS communication with the Growatts, I'm finding that using 'voltage' numbers is VERY difficult. If I could you percentages % SOC of battery power, I think life would be much easier. For example: Right now it is 10:18 AM and my batteries SOC is around 45% and voltage is 51.8 volts. At 10:00 AM just 18 minutes ago the Growatts kicked over to accepting grid-power and started charging the batteries. Yeah, that is cool... kinda. It ONLY charged the batteries for 5 minutes. Battery voltage went from 51.6 to 54.3 volts, and the charging stopped. Again, my SOC is still hovering around 45%....

Am I wrong to assume that IF I had BMS communication to the Growatts I would be able to program this much easier???

Secondly, how to I tell the Growatts (some programming setting???) to keep pushing power into the batteries during the time frame 10 AM to 3 PM? I cannot tell if the battery BMS say I'm full and don't want any more charging (even though the SOC can be down to 18%) , or the Growatts are saying the batteries don't want charging. Any ideas?

Growatt settings:

#1 SBU
#2 50A
#4 US2
#11 80A
#12 50.0V
#13 50.5V
#14 SNU
#19 56.0V
#20 56.0V
#21 44.0V
#49 1015

I'm willing to somewhat sacrifice my battery longevity by charging them and topping them off every day. Hopefully I will use my batteries (adding more and more power loads to the second electrical panel as possible) and the SOC at 10 am is rather low and will need to be charged.

Thank you 10 times over if you read this all the way to the bottom.

Thank you 100 times if you help me solve my problem.

I love this DIY stuff, makes my head gird!

Looking forward to any helpful suggestions.

Thanks much.

Dave

 

[Ddowie]

Hi,
I also have two growatt 5000 se inverters, battery and grid for backup.

What else do I need to be able to send excess of energy back to grid?

I appreciate your anwser a lot

Have a great day!

 

[Zwy]

7) There isn't any solar panels input connected to my Growatts. AC power input only.

I'd wire some PV directly to the GW. More efficient and you will have some power during an outage.

My Goal: My goal is to capture as much solar power during the peak hours of 10 am to 3 pm and fill my batteries during this time. This power will come from my original grid-tied house electrical panel via (2) 2P40 amp breakers one to each of the 2 Growatts. During this time my panels are producing more than my house requires and thus, sending excess power back to the grid (of which they only pay 1/10th rate for my production). I want this excess power to go into my batteries and use that battery power at night. Hope this all make sense. (sorry for the "Gone with the Wind" length of explanation...)

Problem: Since I don't have BMS communication with the Growatts, I'm finding that using 'voltage' numbers is VERY difficult. If I could you percentages % SOC of battery power, I think life would be much easier. For example: Right now it is 10:18 AM and my batteries SOC is around 45% and voltage is 51.8 volts. At 10:00 AM just 18 minutes ago the Growatts kicked over to accepting grid-power and started charging the batteries. Yeah, that is cool... kinda. It ONLY charged the batteries for 5 minutes. Battery voltage went from 51.6 to 54.3 volts, and the charging stopped. Again, my SOC is still hovering around 45%....

Looking at the settings below, I have to wonder if the battery cells have become unbalanced.

Am I wrong to assume that IF I had BMS communication to the Growatts I would be able to program this much easier???

It shouldn't really matter.

Secondly, how to I tell the Growatts (some programming setting???) to keep pushing power into the batteries during the time frame 10 AM to 3 PM? I cannot tell if the battery BMS say I'm full and don't want any more charging (even though the SOC can be down to 18%) , or the Growatts are saying the batteries don't want charging. Any ideas?

Growatt settings:

#1 SBU
#2 50A
#4 US2

I do know on many GW models, you would be better served with USE. Usually USE2 doesn't allow the float setting to be set for a desired offset from bulk.

#11 80A
#12 50.0V

Have to ask why so high?

#13 50.5V
#14 SNU

#19 56.0V

Move closer to 58.0V

#20 56.0V

I prefer 0.5V below bulk so 57.5V. You can use 58.0V

#21 44.0V
#49 1015

I'm willing to somewhat sacrifice my battery longevity by charging them and topping them off every day. Hopefully I will use my batteries (adding more and more power loads to the second electrical panel as possible) and the SOC at 10 am is rather low and will need to be charged.

Thank you 10 times over if you read this all the way to the bottom.

Thank you 100 times if you help me solve my problem.

I love this DIY stuff, makes my head gird!

Looking forward to any helpful suggestions.

Thanks much.

Dave

 

[Dank Farrik]

Hi,
I also have two growatt 5000 se inverters, battery and grid for backup.

What else do I need to be able to send excess of energy back to grid?

I appreciate your anwser a lot

Have a great day!

You need to talk to your local electrical utility about that. There are a lot of rules and regulation for grid tied solar, for example, by law a grid tied system requires an automatic rapid shutdown mechanism when the grid loses power. Where I live, you can't unless the install is done by an authorized solar installer and passes a city inspection.