JK BMS - Cell Over Voltage Protection problem

[Jane]

I bought JK-B2A24S20P and started testing it with 16 battery cells (3.2V 280Ah each ).
Parameters are set - please see pictures.
Setting works for only small charging current upto about 2 Amps. When rising to about 9Amps, the charging stops and JK BMS reports Cell Over Voltage Protection error.
How should I set JK BMS so that it will work with current higher than 2 Amps?

My JK BMS setting is here
Thank you

 

[rickst29]

What are your cell voltages, highest/ lowest/ average?

(SWAG - you might have a loose busbar or BMS sense wire affecting this)

 

[Steve_S]

The new jk manual:

JK/JKBMS INSTRUCTION.pdf at JK-BMS · NEEY-electronic/JK

Contribute to NEEY-electronic/JK development by creating an account on GitHub.

github.com

Also check this for tweakages. Just in recovery from more surgery's and somewhat spaced. Also the wires & termination are 80% of problem causes... Gotta be perfect.

Steve_S-Tech: My Final Config for Midnite Classic SCC & JKBMS' w/ Large Bank (works amazingly well) Includes Charge Profile & BMS Config

INTRO: I have debated posting this for a while until I got everything tweaked in and working as best as possible. The End Result is Gobsmackingly Good ! I cannot speak for other SCC and such as each is different & unique in their own ways BUT this may likely be a Good Reference. Civility &...

diysolarforum.com

Hope it helps.
Steve

 

[Jane]

Thank you for your replies.
Yes, there were 2 loose busbars

 

[hwse]

Is there a reason why you set your OVP to 3.65V? I personally like to have some headroom at the top limit rather than allowing it to be pushed to the max.

 

[RV10flyer]

Is there a reason why you set your OVP to 3.65V? I personally like to have some headroom at the top limit rather than allowing it to be pushed to the max.

Oh, there's plenty of headroom. Your inverter should not be charging above 3.55 per cell anyway.

 

[burgerking]

Might I remind you: JK does not trigger OVP instantaneously.
JK samples the cells several times and it takes ~5s seconds before it disconnects Charger.
And if your Charger delivers high current, it can and will drive this voltage to 3.8 easily!

My original setting was 3.60V then 3.55V. I went down to 3.50V; at this level it is practically >99% SOC already.

PS. Your Power Off voltage is too low... go 2.6V

 

[hwse]

Might I remind you: JK does not trigger OVP instantaneously.
JK samples the cells several times and it takes ~5s seconds before it disconnects Charger.
And if your Charger delivers high current, it can and will drive this voltage to 3.8 easily!

My original setting was 3.60V then 3.55V. I went down to 3.50V; at this level it is practically >99% SOC already.

PS. Your Power Off voltage is too low... go 2.6V

My setup is on a sailboat, so I have the bottom end set very conservative. I have LVC at 3.0 and LVCR at 3.1. That way I still have significant capacity after the BMS cuts off. My running lights and navigation equipment is supplies by the LFP house battery I have set it that way so that I will still have a significant capacity after the initial shutdown. Then I can turn off all one mission critical loads and lower the LVC to 3.7 to allow me time to get to a safe harbor.
I also set my HVC to 3.55 (14.2v) with tail current controlled absorption. This will get the full capacity without driving the voltages up to the limit.

 

[burgerking]

WOW! Same here with the boat!
I am in the process of doing just that too!
Using noisy generators at night is not relaxing!

 

[hwse]

WOW! Same here with the boat!
I am in the process of doing just that too!
Using noisy generators at night is not relaxing!

I am completely happy with my installation. I have 560Ah with a JK BMS in a 2p4s configuration.

 

[Jane]

Might I remind you: JK does not trigger OVP instantaneously.
JK samples the cells several times and it takes ~5s seconds before it disconnects Charger.
And if your Charger delivers high current, it can and will drive this voltage to 3.8 easily!

My original setting was 3.60V then 3.55V. I went down to 3.50V; at this level it is practically >99% SOC already.

PS. Your Power Off voltage is too low... go 2.6V

@burgerking: Can you please post your battery parameters setup?
Thank you

 

[burgerking]

 

[Jane]

@ burgerking: Thank you !

 

[dakamalu]

I bought JK-B2A24S20P and started testing it with 16 battery cells (3.2V 280Ah each ).
Parameters are set - please see pictures.
Setting works for only small charging current upto about 2 Amps. When rising to about 9Amps, the charging stops and JK BMS reports Cell Over Voltage Protection error.
How should I set JK BMS so that it will work with current higher than 2 Amps?

My JK BMS setting is here
Thank youView attachment 105490View attachment 105491View attachment 105492

I have the same device. In fact, I am on my third one because the first two failed for other reasons that I have posted elsewhere.
I also had this problem when I installed a new BMS, but when I let the battery drain, the problem went away for me when it charged up again.

Don't know why!

 

[dakamalu]

@burgerking: Can you please post your battery parameters setup?
Thank you

Are you saying that the Victron Chargers don't actually hold the voltage settings?

 

[hawe]

I am completely happy with my installation. I have 560Ah with a JK BMS in a 2p4s configuration.View attachment 106467

Hi hwse!

I have read some of your post and i'm in the process of doing the same installation om my boat, but 2P4S with 320 Ah cells, same same.

Can you please share your settings in JK BMS?
I suppose I need to double my Ah for the cell because of 2P4S set-up, but I don't really get it...

My thoughts and concerns are mostly around alternator protection and dc - dc charger.
I have ordered a Sterling Alternator Protection device, so one less concern, I hope...
I will connect our alternator directly to LifePo4 and maybe using a dc - dc charger for the start battery. Its an old school alternator so its a bit of a gamble, will go for a Balmar later (when my lottery ticket mach my needs).

If you have a drawing of your set-up you can share it would be very much appreciated!

Thanks for charing your set-up here on DIY solar, have been very useful for me.

All the best
Håkan

 

[hwse]

with a 2p setup with 320Ah cells your capacity would be 640Ah
I charge to 13.8v and set my OVP to 3.65v and UVP to 3.1v.
I charge directly from a 250A externally regulated alternator that has the output limited to 190Ah and temperature-controlled limiting.
I do not use an alternator protection device. instead, I have an ArgoFET isolator, so the alternator is continuously connected to the AGM start battery for a dump load incase the bms shuts off. If you search for my posts, i have lots of details on my setup.