16s parallel BMS needed (120A+)

[MullerEnergy-Australia]

I need to put four 48V batteries in parallel, any suggestions what BMS I can use? I would strongly prefer if it didn't need ethernet to connect to each other.

Thanks!

 

[Bleedingblue]

I"m in the process of building 6 strings of batteries and each of the 6 has their own bms

 

[Steve_S]

Ethernet Cable ??? WHAT ?
We can suggest several BMS' but not with this little info.
What batteries, cells. What AMP Rating ?
How many amps are you building for ?
Is there a requirement for Cold Temp monitoring (LFP cannot be charged below freezing).
What exactly would you ant the BMS to do, Smart with BlueTooth interface or PC Software interface or what....

 

[MullerEnergy-Australia]

Ethernet Cable ??? WHAT ?
We can suggest several BMS' but not with this little info.
What batteries, cells. What AMP Rating ?
How many amps are you building for ?
Is there a requirement for Cold Temp monitoring (LFP cannot be charged below freezing).
What exactly would you ant the BMS to do, Smart with BlueTooth interface or PC Software interface or what....

Okay, yes, I should have included that info.
76Ah Lishen cells
The four batteries together have to be able to do 450A peak.
No cold temperature disconnect or comms needed.

Thanks very much!

I've found out that Chargery can do this, however they are quite expensive, especially if you need 4 of them. Do you know of any alternatives?

 

[Steve_S]

Okay, yes, I should have included that info.
76Ah Lishen cells
The four batteries together have to be able to do 450A peak.
No cold temperature disconnect or comms needed.

Thanks very much!

I've found out that Chargery can do this, however they are quite expensive, especially if you need 4 of them. Do you know of any alternatives?

not quite.
48V, = 16 Cells to make One Complete Battery Pack with BMS.
you will get 48V/76AH/3,891Wh (3.8kWh). Max output @ 1C = 76AH, Max Charge Rate @ 0.5C = 38A.
Four Battery Packs in Parallel can handle 305A output @ 1C "Collectively as they all share Load & Charge. The MAX charge handling 152A.
IF one pack cuts off during Charge / discharge you'll be in trouble at these rates.

450A ? Really, NOT, that's nonsense. Where did you get that ?

 

[MullerEnergy-Australia]

not quite.
48V, = 16 Cells to make One Complete Battery Pack with BMS.
you will get 48V/76AH. Max output @ 1C = 76AH, Max Charge Raste @ 0.5C = 38A.
Four Battery Packs in Parallel can handle 305A output @ 1C "Collectively as they all share Load & Charge. The MAX charge handling 152A.
IF one pack cuts off during Charge / discharge you'll be in trouble at these rates.

450A ? Really, NOT, that's nonsense.

I know 76A is the rated continuous output, but I find that prismatic LiFePO4s can be pushed a lot harder than that and feel that going to just over 1.5C peak should be much of a problem. If you see this otherwise, please let me know. You obviously have a lot of knowledge.
450A is peak and for all four packs and the peak output, not continuous.

Charging will never get close to 0.5C, more like 0.1C, so that won't be an issue.

 

[Steve_S]

Yeah, you might say a bit of knowledge... ;-)
Please... don't figure yourself into a heap of trouble, do anything beyond th PRECISE specs and it is your risk & money, do it in a disposable building. I cannot understate the fact that ALL Lithium is Extremely sensitive and NOT forgiving, remember things are registering in Millivolt accuracy ranges. IE No Futsing about !

 

[MullerEnergy-Australia]

Yeah, you might say a bit of knowledge... ;-)
Please... don't figure yourself into a heap of trouble, do anything beyond th PRECISE specs and it is your risk & money, do it in a disposable building. I cannot understate the fact that ALL Lithium is Extremely sensitive and NOT forgiving, remember things are registering in Millivolt accuracy ranges. IE No Futsing about !

But the cells are even rated at 2C for 30s, so I'm not going outside the specs. I'm just saying that these are likely fine to draw 2C continuously, going by other prismatic cells I've played with. But that's not what I'm proposing here at all and I am staying inside the specs.
Even if one battery failed, I'd still be marginally within the 2C peak rate.

Would you happen to know a BMS that can do this and doesn't cost an arm and a leg?

By the way, I'm more than happy to hear your constructive criticism if you still don't think it would work. At the end of the day, I'm here to learn.

 

[Steve_S]

JBD BMS' are popular, Good US Supplier here, one of our members too. https://diysolarforum.com/threads/j...is-there-community-interest.23922/post-306661

 

[MullerEnergy-Australia]

JBD BMS' are popular, Good US Supplier here, one of our members too. https://diysolarforum.com/threads/j...is-there-community-interest.23922/post-306661

Thanks, I've contacted JBD and they've stated that officially only their 4s BMS supports paralleling. Do you know it would work for a fact?

 

[Steve_S]

I haven't got one in Parallel but others do and seems to be Fine. Parallel is not really an issue. BMS' in Series most certainly can be problematic, some can and others cannot.