Smart BMS-Parallel Batteries Compatible?

riverbug · Feb 16, 2023

I was considering the JK B2A8S20P for my 24v LF280K batteries in which I would have two banks wired in parallel. However, I saw in one of Off Grid Garage videos (8 months old) that these are not compatible for use in parallel battery banks. I sent an email to Jikong Technology to verify this as it is not mentioned on AliExpress. No response.
I'm wondering if the reason might have to do with it being a "smart" BMS that has the active balancing? I'm looking for two 24v 8s capable of at least 200 continuous amps to be used in parallel. It does not have to have active balancing, it just seemed like a good idea. Anyone know for sure whether active balancing would be the reason a BMS would not be compatible with parallel configs? Or, is there something else I need to be looking at to determine if a BMS would work for my configuration?
Thanks.

timselectric · Feb 16, 2023

I have them in parallel.
Not sure what the issue would be.
Which video are you talking about?

BentleyJ · Feb 16, 2023

It depends if the configuration is really 8S2P or 2P8S. Since you did say your configuration would be 2 separate 24V battery banks in parallel there shouldn't be any problem. Each set of 8 cells will have its own BMS and active balancer, so no conflict.

In the other configuration its just 1 big battery bank and if 2 x 200A BMS were used to get the necessary 400A total then yes the active balancers would "fight" each other since they are both connected to the same 2 cell group.

riverbug · Feb 16, 2023

timselectric said:
I have them in parallel.
Not sure what the issue would be.
Which video are you talking about?

At 6m 22s in this video it shows...

Again, it was when it was first released so maybe they've modified the restrictions since then as I don't see anything on the webpage currently that references series or parallel configuration issues.

riverbug · Feb 16, 2023

BentleyJ said:
It depends if the configuration is really 8S2P or 2P8S. Since you did say your configuration would be 2 separate 24V battery banks in parallel there shouldn't be any problem. Each set of 8 cells will have its own BMS and active balancer, so no conflict.

In the other configuration its just 1 big battery bank and if 2 x 200A BMS were used to get the necessary 400A total then yes the active balancers would "fight" each other since they are both connected to the same 2 cell group.

Oh, I bet that's it. I didn't think about the single bank series/parallel configuration. So would mine be the 8S2P acronym? 8 cells, 2 banks?

BentleyJ · Feb 16, 2023

riverbug said:
Oh, I bet that's it. I didn't think about the single bank series/parallel configuration. So would mine be the 8S2P acronym? 8 cells, 2 banks?

Yes,

timselectric · Feb 16, 2023

riverbug said:
At 6m 22s in this video it shows...

Again, it was when it was first released so maybe they've modified the restrictions since then as I don't see anything on the webpage currently that references series or parallel configuration issues.

He said he was going to ask about it. Not sure if he did or not. But he also said that he didn't know why it said that it shouldn't be paralleled.
I don't know why either. I only know that he, I, and others are currently running them in parallel.
But that was a 4s model, so it might be different.

riverbug · Feb 16, 2023

timselectric said:
He said he was going to ask about it. Not sure if he did or not. But he also said that he didn't know why it said that it shouldn't be paralleled.
I don't know why either. I only know that he, I, and others are currently running them in parallel.
But that was a 4s model, so it might be different.

That one was 4s/8s, it actually had the 8 leads but he only hooked up four of them. Maybe they've modified that too by now. And he didn't mention that topic in the next video so that's why I was researching. Thanks for the responses; it's good to know others are using them without issues in parallel. I just wasn't sure what the issue would be or what to look for. Always appreciate the knowledge people share in this forum!

riverbug · Feb 16, 2023

BentleyJ said:
Yes,

Thanks. Appreciate the help!

Steve_S · Feb 17, 2023

JK's operate fine in Parallel Installations, I myself run 6 packs in Parallel and all using JK's.
Note the instructions also show that each battery pack is to be appropriately fused using Class T Fuses in the diagrams. You can also use MRBF Fuses but only for battery packs up to 24V (they don't support 48-60V).
Yes, I am the Steve_S who edited their manuals and NO I do not support JK or have any affiliations with them, I just edited teh manuals to help everyone make sense of the former Chinglish that it was.

Required Clarifications !
A Battery = A Number of cells connected together in series with a BMS = 1 Battery Pack. This can be 4 cells for 12V, 8 Cells for 24V, 16 cells for 48V.
A Battery Bank = A Number of battery packs installed in Parallel. This can be 2 Packs or more on one common DC Bus. Each Pack in a Bank is an independent entity as each has it's own BMS.

A 12V Lead Acid Car Battery has 4 cells within it but it is still just one battery. Put 4 Car Batteries in Parallel and you have a Bank of Car Batteries. Some folks just never get it...

riverbug · Feb 17, 2023

Steve_S said:
JK's operate fine in Parallel Installations, I myself run 6 packs in Parallel and all using JK's.
Note the instructions also show that each battery pack is to be appropriately fused using Class T Fuses in the diagrams. You can also use MRBF Fuses but only for battery packs up to 24V (they don't support 48-60V).
Yes, I am the Steve_S who edited their manuals and NO I do not support JK or have any affiliations with them, I just edited teh manuals to help everyone make sense of the former Chinglish that it was.

Required Clarifications !
A Battery = A Number of cells connected together in series with a BMS = 1 Battery Pack. This can be 4 cells for 12V, 8 Cells for 24V, 16 cells for 48V.
A Battery Bank = A Number of battery packs installed in Parallel. This can be 2 Packs or more on one common DC Bus. Each Pack in a Bank is an independent entity as each has it's own BMS.

A 12V Lead Acid Car Battery has 4 cells within it but it is still just one battery. Put 4 Car Batteries in Parallel and you have a Bank of Car Batteries. Some folks just never get it...

Thanks for the information Steve, learned something new again. But wow, no need for the snide remark. I never would have gotten it if nobody ever shared it. So again, thanks for sharing so I can learn.

Steve_S · Feb 17, 2023

Snide ? Really...

HRTKD · Feb 17, 2023

Steve_S said:
Snide ? Really...

Beats me. I had to go back and read your post again to see what that referred to.

Steve_S · Feb 17, 2023

HRTKD said:
Beats me. I had to go back and read your post again to see what that referred to.

I've re-read it a couple of times... No Clue either... must be those danged Invisible Pixels.
Maybe he did not like my "Required Clarifications !" which is for everyone's benefit as SOME folks just cannot grasp what a battery is compared to a battery bank like that "dud"e in Sunny Hot Ozland.

riverbug · Feb 17, 2023

Steve_S said:
I've re-read it a couple of times... No Clue either... must be those danged Invisible Pixels.
Maybe he did not like my "Required Clarifications !" which is for everyone's benefit as SOME folks just cannot grasp what a battery is compared to a battery bank like that "dud"e in Sunny Hot Ozland.

My apologies if I read too much into it. The last line says “some folks just never get it”.

timselectric · Feb 17, 2023

riverbug said:
My apologies if I read too much into it. The last line says “some folks just never get it”.

You're not alone, I felt it too.
But, I don't think that it was intended to be insulting.
It just came out that way.

mill · Feb 17, 2023

Steve_S said:
JK's operate fine in Parallel Installations, I myself run 6 packs in Parallel and all using JK's.
Note the instructions also show that each battery pack is to be appropriately fused using Class T Fuses in the diagrams. You can also use MRBF Fuses but only for battery packs up to 24V (they don't support 48-60V).
Yes, I am the Steve_S who edited their manuals and NO I do not support JK or have any affiliations with them, I just edited teh manuals to help everyone make sense of the former Chinglish that it was.

Required Clarifications !
A Battery = A Number of cells connected together in series with a BMS = 1 Battery Pack. This can be 4 cells for 12V, 8 Cells for 24V, 16 cells for 48V.
A Battery Bank = A Number of battery packs installed in Parallel. This can be 2 Packs or more on one common DC Bus. Each Pack in a Bank is an independent entity as each has it's own BMS.

A 12V Lead Acid Car Battery has 4 cells within it but it is still just one battery. Put 4 Car Batteries in Parallel and you have a Bank of Car Batteries. Some folks just never get it...

Sorry, i have to tell you that there are six cells to a 12 volt lead acid battery.
Martin.

Smart BMS-Parallel Batteries Compatible?

riverbug

New Member

timselectric

If I can do it, you can do it.

BentleyJ

Solar Wizard

riverbug

New Member

riverbug

New Member

BentleyJ

Solar Wizard

timselectric

If I can do it, you can do it.

riverbug

New Member

riverbug

New Member

Steve_S

Offgrid Cabineer, N.E. Ontario, Canada

riverbug

New Member

Steve_S

Offgrid Cabineer, N.E. Ontario, Canada

HRTKD

Boondocker

Steve_S

Offgrid Cabineer, N.E. Ontario, Canada

riverbug

New Member

timselectric

If I can do it, you can do it.

mill

New Member

Similar threads