I have 2 Sunsynk (Deye) 5Kw connected in parallel, configured with two 10Kw lithium batteries (GeneralGold).
They charge normally until they get fully charged then they start self consume down to ~95% then start charging up again.
Primary inverter charges it while the secondary consumes or vice versa ONLY when fully charged, sometimes charge or discharge happen within 2 seconds on the same inverter.

The batteries are brand new, not sure where to start debugging. Any help/guidance is appreciated.


Battery specs:

Same inverted within seconds:

Battery





Battery Config:







System Work:





Master Config:






Secondary Config:






Connection between inverter and batteries:

Edited August 15, 20232 yr by Chrislo
Added more images for the setup

Hey Christo - Remenisent of my CFE batteries cycling between 90-100%, then 95-100% after a firmware update then pinned at 100% after yet more updates - i'd look to get an official explanination from the manufacturer/importer and maybe your installer can help shed some light as well...maybe check that the parallel connection is working as expected - i'm assuming you have no errors stored? - also you don't mention if you have solar installled or not?

Thanks for the reply
The system is connected to solar panels (28 panels).

The output from the solar panels fluctuate (3kw to 0.5kw) when the batteries are fully charged and become unstable with inverters switching charge/discharge until they get down to 95% charge.
 

Should I disconnect the batteries until the technician can have a look? 
 

5 hours ago, Chrislo said:

Thanks for the reply
The system is connected to solar panels (28 panels).

The output from the solar panels fluctuate (3kw to 0.5kw) when the batteries are fully charged and become unstable with inverters switching charge/discharge until they get down to 95% charge.
 

Should I disconnect the batteries until the technician can have a look? 
 

It is sounding a bit like a the parallel setup is not functioning properly can you possible post a picutre of the screen of your two inverters on the section which shows master/slave settings? one inverter would be setup as master and one as slave.

Do you have one battery connected to each inverter or both going to one inverter?

The switching you're descripting does it sound like a solenoid type switching on the battery end or is it on the inverter(s) side?

Sorry for so many questions - the more info the better someone can help - i might not be able to but at least we would have more info to try figure it out if its only a settings issue ... 

Edited August 14, 20232 yr by TheMafiaMan - NotMuffinMan

Good morning

Working with the information we have

Perhaps the work mode is set to discharge the battery to 95% on the inverter and one or the other inverter is trying to achieve this?

Please post a screenshot of the inverters word mode screen and also how are they connected specifically

Regards

One of my friends had same issue with his batteries which then got fixed by a firmware upgrade of the batteries BMS.
He runs Deye and BSL batteries.

Collected the requested info to add to the above:

Battery Config:







System Work:





Master Config:






Secondary Config:






Connection between inverter and batteries:

23 hours ago, TheMafiaMan - NotMuffinMan said:

It is sounding a bit like a the parallel setup is not functioning properly can you possible post a picutre of the screen of your two inverters on the section which shows master/slave settings? one inverter would be setup as master and one as slave.

Do you have one battery connected to each inverter or both going to one inverter?

The switching you're descripting does it sound like a solenoid type switching on the battery end or is it on the inverter(s) side?

Sorry for so many questions - the more info the better someone can help - i might not be able to but at least we would have more info to try figure it out if its only a settings issue ... 

Both batteries are connected together then connected to both inverters.




When fully charged a small buzzing sound happens every few minutes in the batteries (they alternate) never happens before fully charged.

8 hours ago, ZS1SCI said:

Good morning

Working with the information we have

Perhaps the work mode is set to discharge the battery to 95% on the inverter and one or the other inverter is trying to achieve this?

Please post a screenshot of the inverters word mode screen and also how are they connected specifically

Regards

Couldn't find an option to set the max charge when setting the battery type to Lithium (00), although can be achieved with custom % or voltage settings.
Temporary I'm intentionally decreasing the charge rate to 0A when they reach ~90% to slow down the charging until a technician can visit.

Shut everything OFF and restart.

Hi

Do you have a manual for the batteries that provides info on the parallel communication for the RS485 ports? 

We'd like to confirm they are correctly talking to one another

[EDIT] Normally COMS#1 goes to COMS#2 for master slave communication, for instance RS-485-1 => RS-485-2(Please verify with manual)

Please ask the technician to wire your terminals correctly, the battery on the right might take more load than the one on the left

Cheers
 

Edited August 16, 20232 yr by ZS1SCI

13 hours ago, ZS1SCI said:

Good morning

Working with the information we have

Perhaps the work mode is set to discharge the battery to 95% on the inverter and one or the other inverter is trying to achieve this?

Please post a screenshot of the inverters word mode screen and also how are they connected specifically

Regards

Hey 

The work mode screen I was referring to

My batteries also had some weird behavior with the BMS overcharging when this was just in normal non Time of Use mode(inverter default charge to 100%)

Now the batteries still charge to 100% but they no longer exhibit the strange BMS behavior. 

Could be related or not

Just for your information

Regards

On 2023/08/15 at 7:56 PM, ZS1SCI said:

Hi

Do you have a manual for the batteries that provides info on the parallel communication for the RS485 ports? 

We'd like to confirm they are correctly talking to one another

[EDIT] Normally COMS#1 goes to COMS#2 for master slave communication, for instance RS-485-1 => RS-485-2(Please verify with manual)

Please ask the technician to wire your terminals correctly, the battery on the right might take more load than the one on the left

Cheers
 

Thanks the wire layout you suggested helped with having equal consumption between the batteries, now the charge capacity are similar.

 

On 2023/08/15 at 10:19 PM, ZS1SCI said:

Hey 

The work mode screen I was referring to

My batteries also had some weird behavior with the BMS overcharging when this was just in normal non Time of Use mode(inverter default charge to 100%)

Now the batteries still charge to 100% but they no longer exhibit the strange BMS behavior. 

Could be related or not

Just for your information

Regards

Thanks for the info, I've set it to 98% just in case one of the batteries has already reached 100% to prevent having an average lower than one fully charged battery while one of the BMS is trying to discharge (one 100% the other 98%). This would help with night charging, do you know any option to control the % with solar panel charging?

I'm still having the same issue but with lower dis/charge rate.

Will be reaching out to a better technician to prevent any damage. Meanwhile I'm intentionally slowing down the charge rate to 0A when they reach 90%.

I've seen that some suggested we use the use battery voltage option instead of lithium configuration, not sure if its recommended.

Edited August 17, 20232 yr by Chrislo

18 hours ago, Chrislo said:

Thanks the wire layout you suggested helped with having equal consumption between the batteries, now the charge capacity are similar.

 

Thanks for the info, I've set it to 98% just in case one of the batteries has already reached 100% to prevent having an average lower than one fully charged battery while one of the BMS is trying to discharge (one 100% the other 98%). This would help with night charging, do you know any option to control the % with solar panel charging?

I'm still having the same issue but with lower dis/charge rate.

Will be reaching out to a better technician to prevent any damage. Meanwhile I'm intentionally slowing down the charge rate to 0A when they reach 90%.

I've seen that some suggested we use the use battery voltage option instead of lithium configuration, not sure if its recommended.

Good morning

In that screen linked for work mode, if you untick grid charge it discharges above the value

Then there is no need to set it to voltage mode for charging

Also @Chrislo did you confirm that parallel communications is working correctly between packs?

Regards

Edited August 18, 20232 yr by ZS1SCI
grammar slammer