JBD / Overkill BMS 120A 4S Lifepo4 in series / parallel

squowse

Solar Enthusiast
Joined
Jan 4, 2021
Messages
368
Who's tried using these in series / parallel?

Any definitive information?

It's this one I'm particularly looking at.
 

chops728

Solar Enthusiast
Joined
Nov 14, 2020
Messages
68
Has anyone tried to parallel (2) BMS on the same battery ( example one 4S1P battery) --curious if this would work
 

curiouscarbon

Science Penguin
Joined
Jun 29, 2020
Messages
2,229
there’s another thread where someone claimed that they asked @OverkillSolar

response: it’s not recommended.

but there’s apparently not a clear reason why to not do so.

and the user did connect two parallel to same pack and apparently it’s been ok and all magic smoke inside.

it’s important to ensure the configurations are compatible with each other
 

HRTKD

Boondocker
Joined
Apr 24, 2020
Messages
7,699
Location
Somewhere South of Denver
I have two 4s batteries, each with its own BMS. Runs fine paralleled to the common bus bars. I've seen the two BMS on one battery thread and I think the guy is nuts (but not clinically nuts). The loss of accurate capacity numbers is one reason to not do this. The counter argument is that most of us are running a shunt to keep track of capacity.
 

squowse

Solar Enthusiast
Joined
Jan 4, 2021
Messages
368
there’s another thread where someone claimed that they asked @OverkillSolar

response: it’s not recommended.

but there’s apparently not a clear reason why to not do so.

and the user did connect two parallel to same pack and apparently it’s been ok and all magic smoke inside.

it’s important to ensure the configurations are compatible with each other
Yeah I think I saw that and it confused me.
 

pinchio

New Member
Joined
Apr 13, 2020
Messages
24
@squowse Can you clarify your question. Are you asking about connecting two BMS to a single 12V (4S) pack OR connecting two 12V (4S) packs each with it's own BMS in parallel configuration? I'm confusing myself now o_O
 

squowse

Solar Enthusiast
Joined
Jan 4, 2021
Messages
368
@squowse Can you clarify your question. Are you asking about connecting two BMS to a single 12V (4S) pack OR connecting two 12V (4S) packs each with it's own BMS in parallel configuration? I'm confusing myself now o_O
The latter - 1 BMS per 4 cells.
I was asking for series or parallel. Or even both.
 

Bob B

Photon Sorcerer
Joined
Sep 21, 2019
Messages
4,365
One of the few well done manuals you are going to find for a Chinese product. He did the manual himself and has a reputation for no nonsense good support.

I'd shoot him an email for further clarification .... or if there is a limit to how many you can put in a series configuration.
 

squowse

Solar Enthusiast
Joined
Jan 4, 2021
Messages
368
Oh thanks I didn't even know about that. I think their listing even used to say " we don't support the bms". Or was that a different company.
My mistake that was Battery Hookup that said they didn't support this BMS. They just sell it. Honest I suppose.
 

GSXR1000

Solar Addict
Joined
Nov 20, 2020
Messages
723
I tried 4p2s with 2 120a bms .. worked but the amp draw was never equal but not a big deal.. so I switched to a 2s4p and one BMS when I found it would start my onan 20210125_100732.jpg
 

GSXR1000

Solar Addict
Joined
Nov 20, 2020
Messages
723
I am new to this... this is what I am calling my 2 configuration maybe my 4p2s is just 2 x 1p4sScreenshot_20210304-201404_Whiteboard.jpg
 

hipringles

Solar Addict
Joined
Jan 31, 2021
Messages
194
Parallel works. Series works.

But... If you're going to create an 8s 24v battery, you might as well use a single 8s BMS instead of two 4s BMS.

Have you tried it (or anyone else on here)? I can't think of a reason it wouldn't work, I just find it odd overkill would say its not recommended. Other battery manufacturers (battle born) also don't seem to like putting their systems into series
 

Bob B

Photon Sorcerer
Joined
Sep 21, 2019
Messages
4,365
Have you tried it (or anyone else on here)? I can't think of a reason it wouldn't work, I just find it odd overkill would say its not recommended. Other battery manufacturers (battle born) also don't seem to like putting their systems into series
Where did you see that they don't recommend it ..... did you see the manual like above that says it's OK?
 
Top