Cell Over Charging in JK BMS

[AshleyL]

I've changed the Charging voltage to 27.4v let see if it behaves similar tomorrow.

Thanks for your input.

Technically, you should start charging at lower voltage 27.2V and hold it there until the voltage deviation becomes less than 10mV.
Once the deviation reaches 10mV, you should increase it to 27.4v.
Repeat until 27.6V*
Bear in mind that 0.6A balance current is really low, thus the balancing gonna take quite some time to complete.

Changing the Cell will help to fix this?

Nope, assuming if all cells have more or less same capacity. You still wanna do a top balancing anyway.

View attachment 205045
This is my current settings

Yup, correct setting.
Pay attention to the voltage though. Since your pack is very unbalanced, you should set the Start Balance voltage to 3.4V first before settling at 3.45V.

 

[gotbeans]

Changing the Cell will help to fix this?

yea as long as the cell you get is close to your other cells hahahaha hard to guess that one.
If that cell is lower capacity and damaged and the others ARE NOT then yea it is a good chance it would fix it

 

[Alkaline]

Yes, happened exactly same as shown in the video!

Cell 8 goes upto 3.700v, all the cells in the battery bank is new

Is this a BMS failure?

No this is because JK and NEEY balancers will ramp up the voltage to 4-5v to balance them faster, NEEY does the samething I verified on my EEL battery, to balance I measured the output voltage, EVEN if I put max 3.65 volts, the bms will pump out 4.5-5.5v ! Way above. This is the reason why the have the magical 2 amp constant balancing.

Solution is to lower the amp output to like .5 amps.

However, I just decided I rather take it slow and safe and use the heltec style active balancers with the capacitors.

 

[karthik_bkv]

Technically, you should start charging at lower voltage 27.2V and hold it there until the voltage deviation becomes less than 10mV.
Once the deviation reaches 10mV, you should increase it to 27.4v.
Repeat until 27.6V*
Bear in mind that 0.6A balance current is really low, thus the balancing gonna take quite some time to complete.



Nope, assuming if all cells have more or less same capacity. You still wanna do a top balancing anyway.


Yup, correct setting.
Pay attention to the voltage though. Since your pack is very unbalanced, you should set the Start Balance voltage to 3.4V first before settling at 3.45V.

@AshleyL , this works.
Now the cells are balanced at 3.5v, no OVP is triggered. Working as expected

Thanks Buddy!! For your suggestion

 

[karthik_bkv]

 

[AshleyL]

View attachment 206974

Perfection at its finest.......Based on the duration between the post.....it sure took long time to balance all the cell.......

 

[ScrotusGobbleBottom]

Perfection at its finest.......Based on the duration between the post.....it sure took long time to balance all the cell.......