My system has been running flawlessly for 3 months and all of a sudden there is no comms between the battery BMS and inverter. 

I restarted the system several times but had no luck.

Any idea what could it be or what my next steps can be. 

Can't sit without backup have a Marine Reef Tank and with the current CPT weather, I will wipe my whole tank if without power for long. 

  

First check your cable. Test each pin for continuity. Maybe a simple cable fault.
 

Thank you, just checked the cable, all ok.

1 hour ago, TheRealChuckNorris said:

Thank you, just checked the cable, all ok.

Push comes to shove you can run the battery in AGM (voltage) setting until the comms can be sorted 

Placed it on AGM setting for now thank you !

36 minutes ago, TheRealChuckNorris said:

Placed it on AGM setting for now thank you !

Make sure youve double checked the settings for AGM on the battery - it will work well. Still key to understand why comms went down so installer prob needs to come out 

Hi there. This happened to me last week as well. How do you change the battery setting to AGM. Did you find the solution yet. Thank you. 

Its. on the battery settings 1st tab, you will see there are 2 AGM options, I just used the voltage one. 

Haven't resolved it yet, ordered a cable just in case  

Same issue for me with the same BX51100 and 5kw Sunsynk. Working well for 3 months and then all of a sudden lost communication. Just wanted to check why changing to AGM in the meantime work well?

Would be interesting to know if any of your inverters got a new firmware loaded or what? Seems too concentrated to be random

I haven't changed anything on the system since it has been installed. Has anyone managed to fix this issue and get back the bms link?

Same happend to me today. Sunsynk 5k + 3 x Bx51100.  Been running for 9 months with no issues till today. 

 

 

Sunsynk have said they have not changed anything on the inverter. I am now awaiting feedback from Dyness to resolve this issue. Currently on AGMv settings in the interim.

 

Sunsynk have said they have not changed anything on the inverter. I am now awaiting feedback from Dyness to resolve this issue. Currently on AGMv settings in the interim.

This is a very very bizarre case - have you tried shutting the whole system down and restarting it again? Might be worth a shot in these eskom filled days

Yes I have restarted the system multiple times.

 

Yes I have restarted the system multiple times.

Tried different network cables? I'm just shooting in the dark here now

Yes I have tried multiple cables and the dyness technician also tried a few.

I still got the same issue, did the cables, restart etc. 

Has anyone tried a factory reset on the inverter? The Dyness guys are adamant that this issue lies with Sunsynk updating something that would have impacted the BMS. Now I am trying to get some feedback from Sunsynk.

We had the same at one site, 16kw with 2 x freedomwon lite 20/16, no issues prior. 

Then all of a sudden BMS comms stopped, no updates to the battery SoC, stayed constant at 80% (as per solar assistant) , until eventually the batteries shut down themselves (lights on battery were red then, so the battery was correctly reading it's own SoC ) 

 

Electrician tried a host of things, eventually factory reset worked to get things up and running. 

 

Concerning nevertheless. 

I am going to attempt a factory reset then , thank you

Please kindly reply back if this works. I haven't brought myself to do this yet but I have seen feedback that it may work. Be sure to take images of your current settings.

The exact same thing happened to me today. 2 x 5kW sunsynks. 3 x 5kW dyness. Working perfectly since Feb. Lost BMS comms today. I have tried everything mentioned here for the past few hours.

Dyness tech says change the cables but from what I'm reading here it's unlikely that this is the problem.

Could someone please share the AGM voltage settings you are using for now.

This is from Dyness:

Shut down 49V
Low battery 50V
Restart 53V

Bulk charge voltage 56.5V

Float charge voltage 55.5V
Cut off voltage 49V
Charge and discharge current 50A