Hello,

I am a new member, I live in Sweden in Kolmarden.

We have a solar system with 14 panels facing east, 10 panels facing south and 14 panels facing west. Unfortunately there was not room for more to the south.

We have a Deye inverter, SUN-12K-SG04LP3 and 3 Greensun 48V200AH powerwall 15S (15 cells), see attachment.

We have had problems with the batteries, that the BMS has stopped working on 2 of them. I have searched for new spare BMS but can't find the same ones.

As the batteries stopped working at different times, they have slightly different statuses.

My idea now is to replace all three BMS with new ones, but I have a hard time deciding which type to choose, many different makes and many different types. 

*what effect should you have

*From what I understand, some works for parallel connection but not others.

*It must be able to communicate with the Deye inverter

*Should it be active or passive balancing?

*Should the BMS have integrated balancing or should it be separate

There are probably more things to think about and mistakes to make, can anyone help me navigate correctly?

Kind regards

@lbert

Datablad_ Manual 48V200AH (2).pdf

@alberth ,

Best bet would be to start with Andy's Off Grid Garage youtube channel: https://www.youtube.com/watch?v=5URxJtiHSAw

On his www page: https://docs.google.com/spreadsheets/d/1E7zX6uXqczvpEEJKD8jER31LWkNqWMgvUytVCVfMvlg/edit?usp=sharing is a spreadsheet to make it easier to decided which BMS to use, depending on you specific use case.

Good luck with your project.

6 hours ago, Sidewinder said:

@alberth ,

Best bet would be to start with Andy's Off Grid Garage youtube channel: https://www.youtube.com/watch?v=5URxJtiHSAw

On his www page: https://docs.google.com/spreadsheets/d/1E7zX6uXqczvpEEJKD8jER31LWkNqWMgvUytVCVfMvlg/edit?usp=sharing is a spreadsheet to make it easier to decided which BMS to use, depending on you specific use case.

Good luck with your project.

Thanks for sharing the link to Andys spreadsheet.

@alberth ,

What I would do in the mean time, is just to run the Inverter & Batteries in Voltage mode - i.e. not Lithium, remove the comms cable, and set the inverter battery charge voltages, etc. to suit your 15S battery.

Top prize would not only be to upgrade all 3 batteries' BMS's, but also to upgrade to 16S architecture, if the battery case can accommodate another cell.

On 2025/09/08 at 7:30 PM, alberth said:

My idea now is to replace all three BMS with new ones, but I have a hard time deciding which type to choose, many different makes and many different types.

JKbms's in my opinion are the best and will communicate nicely with each other and your inverter.
And they have a great app to manage them and set all the correct settings.
They also integrate very well with homeassistant

and as @Scorp007 already mentioned, definitely go look at Andy's youtube channel.

and definitely as @Sidewinder mentions, try making them into 16s batteries, worth the effort, i did that to all my batteries and they work way better now :)

Edited September 10, 2025Sep 10 by WannabeSolarSparky

Thanks for all the tips, I'll try to get some time this weekend to look at the spreadsheet to get a better understanding. I will surely come back with more questions.

Hey, better late than never.

After much reading and watching many videos, I came to the decision to switch to JK/Jikong BMS. The JKBMS PB2A16S15P 7S-16S Active Balance Inverter BMS Balance Current 2A Continuous Current 150A Family Energy Storage, Version 19, three of it and a display.

I installed the BMS temporarily, to check the function. The first battery started immediately and the inverter communicated with it. Then I installed and plugged in the other two which immediately appeared in the BMS display. It was more difficult to establish whether all three were involved in the communication with the inverter. Via RS 485 I connected the master battery via the Pi computer to the Solar Assistant where I could monitor the batteries remotely.

As it seems to be working to my satisfaction I made new mounting plates which I installed the BMS on, I have started to install but still missing some material, will report back when everything is in place.

@lbert