Can an 8s BMS be used in a 5s or 6s pack?

[BlitzSSS]

Hi All

Can a BMS designed for 24v or 8s cells generally be used for a lower voltage and smaller cell count pack i.e 5s or 6s?

JBD BMS's specifically which I'm hoping I can just program for the correct values. I'm awaiting a response from JBD on Alibaba so thought I'd ask here too.

Apart from their 8s products, they have other models for 3s-8s and specifically mention 3, 4,6,7 and 8s but skipping 5s in this listing. Not sure if this is just because 5s is so rare or it is a specific limitation of the BMS/programming.

Thanks

 

[MisterSandals]

Hook it up as 5S and see what the app says. It may just work or it may say that you are missing 3 leads.

 

[BlitzSSS]

Thanks but I don't have any BMS or the cells just yet so hoping to make an informed decision before purchase.

Hoping someone here may know.

 

[Supervstech]

There are some BMS boards out there that can be used with varying banks, but they are usually the cheaper line.
If protecting a good expensive bank of cells... it is wise to get a tailored high quality dedicated BMS designed for the bank.

 

[Burke]

Generally no they are setup for a specific number of cells, but as @Supervstech has indicated there are some BMS that can handle different numbers of cells. I know the Chargery BMS does 2-8 or 2-16 cells depending on which model you buy.

 

[RStone13]

Hi All

Can a BMS designed for 24v or 8s cells generally be used for a lower voltage and smaller cell count pack i.e 5s or 6s?

JBD BMS's specifically which I'm hoping I can just program for the correct values. I'm awaiting a response from JBD on Alibaba so thought I'd ask here too.

Apart from their 8s products, they have other models for 3s-8s and specifically mention 3, 4,6,7 and 8s but skipping 5s in this listing. Not sure if this is just because 5s is so rare or it is a specific limitation of the BMS/programming.

Thanks

Hopefully when you purchase BMS it comes with leads

 

[A.Justice]

Bumping this thread in hopes that someone may have an answer now. I'm trying to build a 5S LiFePO4 pack.

 

[Supervstech]

Bumping this thread in hopes that someone may have an answer now. I'm trying to build a 5S LiFePO4 pack.

Google is your friend…

 

[A.Justice]

Google is your friend…

When I Google the same thing, I get entirely different results, even double checked my spelling.

Weird.

 

[A.Justice]

And when I look up the BMS's that were shown on your Google specifically, a lot of them are just technical errors on advertising. When you actually click on the BMS, you see the only one available is 5S LTO, and the other one offers a drop-down selection, none of them include 5S.

Believe it or not, I actually did do quite a bit of looking myself before asking. ?

 

[Supervstech]

Weird, several of them list 18V 5S what amperage are you wanting it for?

 

[A.Justice]

Weird, several of them list 18V 5S what amperage are you wanting it for?

An absolute minimum of 60, but I prefer closer to 100. The only 5S ones I've seen available have been for li-po, and not programmable.

That Google search result thing is incredibly odd. I know everyone's account is custom tailored to them, but I didn't get a single one of the results you did on the first page, yours were much more relevant.

 

[A.Justice]

I found this one, but it $10 it seems a little suspicious.

https://www.amazon.com/LiFePO4-Battery-Protection-Circuit-Board/dp/B07JWBDFB2

 

[Symbioquine]

If you get/have an Overkill BMS (or possibly another JBD BMS) you can refer to the Overkill Solar guide on alternative cell count configuration: https://overkillsolar.com/2023/06/30/bms-configuration-for-alternative-cell-counts/

Arguably this thread should be moved into the Danger Zone.

 

[A.Justice]

If you get/have an Overkill BMS (or possibly another JBD BMS) you can refer to the Overkill Solar guide on alternative cell count configuration: https://overkillsolar.com/2023/06/30/bms-configuration-for-alternative-cell-counts/

Arguably this thread should be moved into the Danger Zone.

I've actually already read that, it says the chips are capable of a fifth cell, but aren't wired to accept one. Weird. I wonder if there would be a way to add a few extra components and make the fifth cell channel active.

 

[A.Justice]

I think I may end up going with a 6S pack and PWM motor speed control. I've already got an 8S, 120a, JBD, and they are supposedly able to do that.