Problem with 2 5kW inverters in parallel with battery

[gohigher]

My setup are 2 5kW hybrid single fase inverters connected in parallel. ( true parallel connection ports )
Battery + and - poles are connected to both inverters. Bms port of the master inverter is connected to the battery. My external power meter is connected to the meter port of the master.


Everything is ok on the master . ( it can see grid import and home usage ) . On the slave on the other hand it's not ok. It doesn't see the grid import or home usage.
Where i live , we have a 3 fase delta grid electricity network what means it's a 3 fase network without a common N ( neuter ) . So i only have l1 , l2 and l3. And between each fase 230v. It's only allowed to connect 5kW on one fase. So i connected the master on fase 1 and 2 and the slave on fase 2 and 3.

Now here are the questions :

How do i set both inverters the best? Master on fase a setting and slave on fase b setting? Or both on fase a setting?
If i set them both on fase a setting i don't get grid or home usage readings on the slave inverter. And if i set slave to fase b setting it does see the readings of the grid and home usage , but after a few seconds i get the f18 error.

Than second question , is it normal that the slave inverter can't see the battery values like temperature ,etc? On the master i can see all values when i push on the bms button. On the slave no values.

Third question :

If you look at the picture i've included , you can see that pv is still produces around 670w and it's sending this power to the battery instead of my home usage. This makes the grid import 3 kW instead of 2.4kW. When there's more power needed from house load the battery should give power instead of loading . Don't understand why this is happening. On an other post on facebook some told be the power of the pv is to low and that's why the inverter sends it to the battery . Don't know if this info is true , because sometime the pv is higher than 1kW and still it's sending the power to the battery instead of my home usage. I want home usage to be covered as much as possible. So that i have to use the grid as minimum as possible.

Hope my questions are clair.

 

[shvm]

Few things:
A. There should be acknowledgment that the two inverters are in parallel.
Usually by displaying another inverter icon.

How do i set both inverters the best? Master on fase a setting and slave on fase b setting? Or both on fase a setting?
If i set them both on fase a setting i don't get grid or home usage readings on the slave inverter. And if i set slave to fase b setting it does see the readings of the grid and home usage , but after a few seconds i get the f18 error.

Please consult the manual on how to parallel them properly for your situation. Usually it also involves managing DIP switches of some kind to prepare the inverters. You may also need to consult the technician or support.

B. The entire PV output is being used to charge the battery. This appears to me as "AC first" mode. The inverter is prioritising battery charging from PV. You may have to dive into settings to turn this time.
Usually it is a time window within which inverter will prioritize AC to power home loads.

C. It is also possible that the battery has become fully discharged recently. In that case, the inverter will try to bring the battery up to a little charge before loading it again.

 

[DIYrich]

Post the inverter model, and link to its manual.

It is more efficient to charge battery directly from PV. You may have it set to use PV to first charge up battery (for later use).

Your inverter may not be able to mix PV and Grid power. So if the inverter cannot fully supply load, it powers the load from the grid.

Knowing what model inverter your have could help give more specific response.

 

[gohigher]

Few things:
A. There should be acknowledgment that the two inverters are in parallel.
Usually by displaying another inverter icon.

Please consult the manual on how to parallel them properly for your situation. Usually it also involves managing DIP switches of some kind to prepare the inverters. You may also need to consult the technician or support.

B. The entire PV output is being used to charge the battery. This appears to me as "AC first" mode. The inverter is prioritising battery charging from PV. You may have to dive into settings to turn this time.
Usually it is a time window within which inverter will prioritize AC to power home loads.

C. It is also possible that the battery has become fully discharged recently. In that case, the inverter will try to bring the battery up to a little charge before loading it again.

A. They have indeed the other icon. I've included the photos. Are they available true whatsapp or messenger?

B. It's now set as load first . Is that what you mean?

C. I'm still figuring out on how all the settings work like the system work mode for example. I've included a photo to.

 

[gohigher]

Post the inverter model, and link to its manual.

It is more efficient to charge battery directly from PV. You may have it set to use PV to first charge up battery (for later use).

Your inverter may not be able to mix PV and Grid power. So if the inverter cannot fully supply load, it powers the load from the grid.

Knowing what model inverter your have could help give more specific response.

The model is sun-5k-sg03lp1-eu
And manual is : https://www.google.com/url?sa=t&sou...IQFnoECBgQAQ&usg=AOvVaw2E0yg3MxGetldzt0g_IgiH

 

[kommando]

Look at section 3.12 in the manual. Follow that section but with only a master and single slave. Note each inverter needs its own CT clamp on the phase its connected to.

 

[gohigher]

Look at section 3.12 in the manual. Follow that section but with only a master and single slave. Note each inverter needs its own CT clamp on the phase its connected to.

That won't work . I'm working with a 3 fase power meter.

 

[kommando]

That won't work . I'm working with a 3 fase power meter.

There is no meter on 3.12, the inverters are told the current flows with the volts giving watts by the CT clamps not by any meter or meters.

 

[gohigher]

There is no meter on 3.12, the inverters are told the current flows with the volts giving watts by the CT clamps not by any meter or meters.

Not sure i understand what you're saying wright now. Because in the inverter menu i set it to my 3 fase meter . Why is there an option then to select external meter in the menu?

 

[kommando]

The CT clamp provides amps and flow direction to the inverter, the inverter knows the voltage so can calculate the KW including direction into or from grid, exactly what a meter would show. The manual and the inverter manual are written in Chinglish, that's bad enough for a native English speaker to not understand let alone someone who's first language is not. Best you contact Sunsynk support and ask what they mean by meter, do they mean the CT clamp or the house meter.

 

[DIYrich]

Everything is ok on the master . ( it can see grid import and home usage ) . On the slave on the other hand it's not ok. It doesn't see the grid import or home usage.
Where i live , we have a 3 fase delta grid electricity network what means it's a 3 fase network without a common N ( neuter ) . So i only have l1 , l2 and l3. And between each fase 230v. It's only allowed to connect 5kW on one fase. So i connected the master on fase 1 and 2 and the slave on fase 2 and 3.

I think your inverter supports WYE 3-phase, and not Delta 3-phase (which is what you have).

While you have L1, L2, and L3 grid lines, your inverter is expecting L1-N, L2-N, and L3-N connections. Unfortunately, you said you don't have an N.

Section 3.12 of the manual is for wiring 3-Phase WYE. There is not a diagram for wiring 3-Phase Delta.

How did you try to wire it? Inverter 1: L1-L3, Inverter 2: L2-L3? Did you setup each as a Master on a different phase?
Note: You won't have L3. Don't know if that will work.

I think you are getting the F18 error because it sees 380v between the L1-L3, and not 220v it would expect between L1-N.

In anycase, try whatever you did, but put both as Master, not Master/Slave.

 

[gohigher]

I think your inverter supports WYE 3-phase, and not Delta 3-phase (which is what you have).

While you have L1, L2, and L3 grid lines, your inverter is expecting L1-N, L2-N, and L3-N connections. Unfortunately, you said you don't have an N.

Section 3.12 of the manual is for wiring 3-Phase WYE. There is not a diagram for wiring 3-Phase Delta.

How did you try to wire it? Inverter 1: L1-L3, Inverter 2: L2-L3? Did you setup each as a Master on a different phase?
Note: You won't have L3. Don't know if that will work.

I think you are getting the F18 error because it sees 380v between the L1-L3, and not 220v it would expect between L1-N.

In anycase, try whatever you did, but put both as Master, not Master/Slave.

The master is on fase 1 and fase 2. The slave is on fase 2 and fase 3.

It can not see 380v because i don't have 380v . Only 3 times 230v between each fase.

If i set then both to master , the won't communicate anymore and it going to behave very weird no?

 

[DIYrich]

The master is on fase 1 and fase 2. The slave is on fase 2 and fase 3.

It can not see 380v because i don't have 380v . Only 3 times 230v between each fase.

If i set then both to master , the won't communicate anymore and it going to behave very weird no?

The 3.12 diagram shows ALL AS MASTER. The manual should know what the software is programed to do. "Master" is needed when two or more inverters put power on the same line. Since each inverter has its own line, each inverter is a Master of its line. Don't know, but I would avoid using Phase 2 (the common line between the two inverters).

This might be helpful:

230V DELTA 3-PHASE configuration? - Victron Community

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