Seplos CAN BUS RS485 48v 200A 8S-16S BMS

[Coda]

I do not know for sure but - as you have a 208mv imbalance, three cells are quite low (C5, C6, C13), and one of the cells is very low (C5) - I believe the BMS is indicating capacity based on those weakest cells.

If those 3 batteries are really OK, I would suspect the balance leads are not tight or have oxidisation.

Someone else with more experience may have better idea.

 

[Sanwizard]

I do not know for sure but - as you have a 208mv imbalance, three cells are quite low (C5, C6, C13), and one of the cells is very low (C5) - I believe the BMS is indicating capacity based on those weakest cells.

If those 3 batteries are really OK, I would suspect the balance leads are not tight or have oxidisation.

Someone else with more experience may have better idea.

Looks like he lost a cell. Please use a DVM to verify voltage on the 3V cell. Perhaps a balance cable came loose or there is gunk on the connection.

 

[mahdi89]

Looks like he lost a cell. Please use a DVM to verify voltage on the 3V cell. Perhaps a balance cable came loose or there is gunk on the connection.

lost a cell within 1 month of use :/ ?

 

[mahdi89]

I do not know for sure but - as you have a 208mv imbalance, three cells are quite low (C5, C6, C13), and one of the cells is very low (C5) - I believe the BMS is indicating capacity based on those weakest cells.

If those 3 batteries are really OK, I would suspect the balance leads are not tight or have oxidisation.

Someone else with more experience may have better idea.

please can you check the seplos history log https://docs.google.com/spreadsheet...ouid=101823743385499957433&rtpof=true&sd=true

 

[houseofancients]

lost a cell within 1 month of use :/ ?

it can happen,especially with b grade or lower cells.
where did you get them if i may ask ?

 

[mahdi89]

it can happen,especially with b grade or lower cells.
where did you get them if i may ask ?

Grad A From Amy wan

 

[Coda]

please can you check the seplos history log https://docs.google.com/spreadsheet...ouid=101823743385499957433&rtpof=true&sd=true

It definitely looks like a cell is the issue. You can see at line 313 where the capacity drops to 9% in an instant. If you scroll down to line 434 you see Monomer Overvoltage warnings with the same cell identified from earlier, now reading 3.538v while the others are around 3.31v (0.2v difference). Tells me the chemistry inside the battery damaged, OR maybe the sense wire for #5 is damaged. I'd check that first.

 

[Coda]

Grad A From Amy wan

Well, she has a good reputation, so it's unlikely to be anything other than 'just one of those things'. I would send her a message, see what she says.

 

[mahdi89]

It definitely looks like a cell is the issue. You can see at line 313 where the capacity drops to 9% in an instant. If you scroll down to line 434 you see Monomer Overvoltage warnings with the same cell identified from earlier, now reading 3.538v while the others are around 3.31v (0.2v difference). Tells me the chemistry inside the battery damaged, OR maybe the sense wire for #5 is damaged. I'd check that first.

can recalibrating(rebalance) fix this issue?!

 

[Coda]

can recalibrating(rebalance) fix this issue?!

I don't know.
Check sense wire first before you take any drastic steps.

 

[mahdi89]

I don't know.
Check sense wire first before you take any drastic steps.

no problem seen..replaced the ring connector.. hope it will get fixed

 

[Kajitis]

the bms has pylontech compatible CANBUS, so it should work

Sorry late responce. Sounds really good

 

[Kajitis]

Sorry late responce. Sounds really good. Thanks!

 

[houseofancients]

Grad A From Amy wan

those should be good cells

 

[Sanwizard]

those should be good cells

I bought a bunch from Amy also, and they are fine. That being said, I would dismantle the battery, re-top balance, and then check all balance cables. Re assemble, and test resistance of your wiring. Maybe use some MG chem anti-oxidation on the connections. Number all your cells before taking it apart. Once reconfigured, if the same cell varies from the others, then you can be pretty sure you have a bad cell. Most likely its just a connection though. Move the suspect cell to a different balance lead location to make sure its not the BMS side.

 

[mahdi89]

I bought a bunch from Amy also, and they are fine. That being said, I would dismantle the battery, re-top balance, and then check all balance cables. Re assemble, and test resistance of your wiring. Maybe use some MG chem anti-oxidation on the connections. Number all your cells before taking it apart. Once reconfigured, if the same cell varies from the others, then you can be pretty sure you have a bad cell. Most likely its just a connection though. Move the suspect cell to a different balance lead location to make sure its not the BMS side.

i did change the ring connectors of that cell loc..
1-may i know how to test resistance?
2-what do you mean by sure its not the BMS side ?

 

[Sanwizard]

i did change the ring connectors of that cell loc..
1-may i know how to test resistance?
2-what do you mean by sure its not the BMS side ?

Use a digital volt meter to test the resistance of the wires leading from the cells to the BMS connector. Also check the individual voltages of each cell AT THE CELL. By the BMS side, I meant the BMS logic itself. Move the suspect cell to a new connection point to see if the issue follows the cell or stays with the same balance lead.

 

[sergea]

Sorry late responce. Sounds really good

I just received the a news version with RS485 pylontech firmware, I need to test them with a mpp solar inverter

 

[houseofancients]

got the same, however, it looks exactly the same, including the canbus port.
have contacted seplos, but maybe you can confirm it is physically the same as their canbus version, as they are having their new year, and it could be some time before i get an answer

 

[sergea]

got the same, however, it looks exactly the same, including the canbus port.
have contacted seplos, but maybe you can confirm it is physically the same as their canbus version, as they are having their new year, and it could be some time before i get an answer

Yep, they warn me the pcb shows canbus information even if it is not. Still waiting the pins connection details for the rj connector.