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Needing help to know which bms to buy please

Ervieus

New Member
Joined
May 24, 2023
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1
Location
France
Hi,

I am new here and need some help to choose a BMS.
I bought 8 Eve 280AH LiFePO4 3.2V cells from Alibaba, and I plan to build two 280AH 12V battery banks with them, that I will use for an off-grid system in my converted van.
I am new to solar and LiFePO4, but if I understand correctly I will need 2 BMS, one for each battery bank in a 2P4S setup, am I right ?


And here comes my main problem, I can't figure out which BMS to buy.
The 2 battery banks will work with this Victron Multiplus and its inverter :
Victron MultiPlus 12/800/35-16 230V VE.Bus Inverter Charger
And those too :
Victron Energy SmartShunt 500 amp Battery Monitor (Bluetooth)
Victron Energy SmartSolar MPPT 100V 50 amp 12/24-Volt Solar Charge Controller (Bluetooth)
Victron Energy Orion-Tr Smart 12/12-Volt 30 amp 360-Watt DC-DC Charger Non-Isolated (Bluetooth)

It seems to me that two 100A BMS will be enough, but maybe I'm wrong and I need 120A or 150A (or even more) ?

I have looked at the Daly products :
Maybe this one Daly Smart BMS LiFePo4 4S 12V 24V 36V 48V 30A 60A 100A 120A 150A 200A 250A 500A Li-Ion BMS 3S 6S 7S 8S 10S 12S 13S 16S 20S 24S ?
Or the CANBUS compatible one BMS LiFePO4 Li-ion 3s 4s 8s 13s 16s 12V 24v 36v 48v 100A 120A 150A 200A 250A 300A 500A LiFepo4 18650 daly smart BMS with CANBUS ?
Or this JBD JBD Smart BMS 3S 12V Li-ion Bms 4S LifePo4 100A 150A Support Series Connection Same Port Balance Built in BT Uart Heat Function ?
Or another model ?
Which one will be the easiest to use for a beginner ?


Thank you in advance for your help, and feel free to ask me more details if needed
 
For 280Ah cells, you might want to consider Active Balance.
I'm curious as to why so many folks here seem to assume there's a need for active balancing.

My assumption is that many are building batteries using cells that have significantly different capacity, or have never taken the time to properly top balance their cells ?
 
I'm new as well you can view my thread and see my 280AH build thread:

They included active balancer so I think for big cells you just need to get it.
 
I'm curious as to why so many folks here seem to assume there's a need for active balancing.

Because you're new, and you haven't been exposed to the 3+ years of issues seen even with top balancing.

My assumption is that many are building batteries using cells that have significantly different capacity, or have never taken the time to properly top balance their cells ?

It's not as cut and dried as that. Putting batteries into storage subjects the cells to their own individual self discharge rates. These are always variable except in premium EV Grade matched cells. Even a 0.1% deviation in SoC can trigger cell OVP. That level of self discharge variation can be seen in as little as a week.

For cells that are placed into service, cycled/charged daily and spend several hours a month at voltages permitting balance do not need anything more than passive balancing. Cells with intermittent use may need more.
 
Because you're new, and you haven't been exposed to the 3+ years of issues seen even with top balancing.



It's not as cut and dried as that. Putting batteries into storage subjects the cells to their own individual self discharge rates. These are always variable except in premium EV Grade matched cells. Even a 0.1% deviation in SoC can trigger cell OVP. That level of self discharge variation can be seen in as little as a week.

For cells that are placed into service, cycled/charged daily and spend several hours a month at voltages permitting balance do not need anything more than passive balancing. Cells with intermittent use may need more.
I'm new here yes, but I've been building energy storage systems using all manner of cells for a couple of decades, the last decade mainly using EV "grade" cells, active balancing is simply a mask for mismatched capacity cells, or an incorrect charge cessation process, but I agree with the content of your penultimate sentence.
 
I'm new here yes, but I've been building energy storage systems using all manner of cells for a couple of decades, the last decade mainly using EV "grade" cells, active balancing is simply a mask for mismatched capacity cells, or an incorrect charge cessation process, but I agree with the content of your penultimate sentence.

The experience of others often varies from one's own. The vast majority of builds are pursued with non EV grade cells. Those results can be highly variable. Many make the mistake of top balancing the cells well before commissioning due to ignorance, poor planning or other circumstances, and those run into problem.

The JK is a popular BMS and it's legit 2A balance current makes balance concerns go away for the most part. That's why active balancing is being pushed more frequently than passive.
 
Hello
Same kinda system in progress to my boat, and thinking of 1 8S 2P on12V seems to be impossible? all seems to "make" 24V system?? this arrange could give me just 1 bms instead of 2!
only 1 to manage is better?
and for max current load i have 15A but to be forward smart (inverter for coffee, microwave, laptop charging, etc) 1500W could use 120A and just for the future 2x 120A bms seems expensive.....

Thanks!
 
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