Best BMS or active balancer for 16S2P 48V 28kwh battery

[kolek]

What is the absolute best BMS and/or active balancer available for a 28kwh battery bank made up of 2 x 16 x 3.2V 280Ah batteries?
Within reason, price is not a major consideration.

Have spent many hours researching and read all the existing threads on this topic, the main options I'm considering are:
REC BMS and JK-BMS but I'm open to other ideas.

Edit: it's a battery bank of 2 batteries, each with 16 cells, and I'm assuming a separate BMS for each

Inverter is Deye All-in-one SUN-8K-SG01LP1-US

https://loja.ensolarenergia.com.br/wp-content/uploads/2020/09/user-manual-deye-502011114%E3%80%90b%E3%80%91SUN-5-8K-SG01LP1-USEU-2MPPT-user-manual-Ver1.7-Deye1.pdf

Still unclear after all my research if I need the BMS's to talk to the Deye so please give your opinion on that if you happen to know. Thank you!

 

[timselectric]

My vote is for JK.
I won't use anything else for my system.

 

[timselectric]

28kwh battery made up of 32 x 3.2V 280Ah batteries?

Single BMS?
I prefer the redundancy of a BMS for each 16s.

 

[timselectric]

Just noticed 16s2p.
That's 2 batteries, my mistake.
I got confused when you said battery, instead of batteries. Or battery bank.

 

[kolek]

Single BMS?
I prefer the redundancy of a BMS for each 16s.

Sorry that was unclear, 2 BMS, one for each 16S, thanks for catching that.

 

[kolek]

My vote is for JK.
I won't use anything else for my system.

I've seen a few people saying things like "The JK-BMS is great but I wouldn't trust it to handle my main battery bank"
Do you think it's robust enough for a battery bank that cost me an arm and a leg and is "mission critical" since I'm offgrid?
Any thoughts about how long it might last before needing replacement?

 

[timselectric]

I personally have not heard anything bad. I've only been using mine for a few months. But, it works flawlessly. I tested all functions, without issues.
The 2 amp active balancing was a big deal in my selection.

 

[timselectric]

My completed system will have 14 batteries, for 200kwh of storage. Each using a JK-B2A24S20P.

 

[Steve_S]

Bang for buck & pound for pound AT PRESENT the JK-BMS by JiKong wins the race.

I've converted my entire fleet to them now.
1190Ah 5 packs in Parallel main bank.
200Ah utility packs.
+1 test pack system.

In fact, I am so impressed with the product line I rewrote their English manual and fully updated that and love running virtually a "perfect" bank.

Steve_S-Tech: My Final Config for Midnite Classic SCC & JKBMS' w/ Large Bank (works amazingly well) Includes Charge Profile & BMS Config

INTRO: I have debated posting this for a while until I got everything tweaked in and working as best as possible. The End Result is Gobsmackingly Good ! I cannot speak for other SCC and such as each is different & unique in their own ways BUT this may likely be a Good Reference. Civility &...

diysolarforum.com

JK/JKBMS INSTRUCTION.pdf at JK-BMS · NEEY-electronic/JK

Contribute to NEEY-electronic/JK development by creating an account on GitHub.

github.com

Hope it helps good luck.
Steve.

 

[kolek]

Steve thanks so much, your comments about them in previous posts were one of the reasons I thought they were a potential "best" option.

 

[Zwy]

Steve thanks so much, your comments about them in previous posts were one of the reasons I thought they were a potential "best" option.

"Best" option can be something that has more capability and not FET based. Batrium is one such BMS, you can run 6 48V batteries off one Watchmon CORE and a K9 for each battery, even more K9's with a power supply. Once you start getting up to 2 16S batteries, the Batrium starts to make more sense long term. If you run 2 Watchmon CORE and 12 K9's, you can split up 12 batteries into 2 banks. That is a huge amount of power and one bank can be shut down while the other continues supplying power.

The amount of amps you can run thru a shunt trip breaker is the only limiting factor. You can expand at any time with just another K9. When I first purchased my Batrium, the plan was 2 16S batteries, I'm already at 3 and may add another. The ABB S5N shunt trip can handle 400A on DC and is rated at 35K Aic which you won't get with FET based BMS's.

 

[kolek]

"Best" option can be something that has more capability and not FET based. Batrium is one such BMS, you can run 6 48V batteries off one Watchmon CORE and a K9 for each battery, even more K9's with a power supply. Once you start getting up to 2 16S batteries, the Batrium starts to make more sense long term. If you run 2 Watchmon CORE and 12 K9's, you can split up 12 batteries into 2 banks. That is a huge amount of power and one bank can be shut down while the other continues supplying power.

The amount of amps you can run thru a shunt trip breaker is the only limiting factor. You can expand at any time with just another K9. When I first purchased my Batrium, the plan was 2 16S batteries, I'm already at 3 and may add another. The ABB S5N shunt trip can handle 400A on DC and is rated at 35K Aic which you won't get with FET based BMS's.

That sounds interesting. Which model Batrium should I be looking at?
Their website for the Watchmon Core says "Advisory: BlockMons availability will be on a by-request basis starting August 2022. Recommend to switch to CellMate-K9."

 

[Rocketman]

Get the Watchmon Core (and expansion board) and two K9’s.

I installed a Batrium in my MotorHome- a 12v 540ah battery. I really like the software for it - user interface is something way too many companies screwup on.

I was originally going to tie the Batrium to my Victron CCGX, but after getting it up and running I haven’t done that. And I am not sure I see the need (but then I don’t push my system hard).

 

[kolek]

"Best" option can be something that has more capability and not FET based. Batrium is one such BMS, you can run 6 48V batteries off one Watchmon CORE and a K9 for each battery, even more K9's with a power supply. Once you start getting up to 2 16S batteries, the Batrium starts to make more sense long term. If you run 2 Watchmon CORE and 12 K9's, you can split up 12 batteries into 2 banks. That is a huge amount of power and one bank can be shut down while the other continues supplying power.

The amount of amps you can run thru a shunt trip breaker is the only limiting factor. You can expand at any time with just another K9. When I first purchased my Batrium, the plan was 2 16S batteries, I'm already at 3 and may add another. The ABB S5N shunt trip can handle 400A on DC and is rated at 35K Aic which you won't get with FET based BMS's.

Get the Watchmon Core (and expansion board) and two K9’s.

I installed a Batrium in my MotorHome- a 12v 540ah battery. I really like the software for it - user interface is something way too many companies screwup on.

I was originally going to tie the Batrium to my Victron CCGX, but after getting it up and running I haven’t done that. And I am not sure I see the need (but then I don’t push my system hard).

@Zwy and @Rocketman , what about the fact that the Batrium (I assume) uses passive balancing vs active with the JK-BMS? Isn't that a major downside?

 

[Rocketman]

To me active balancing was not important. When I am balancing in the absorbing phase I am then in a “power rich” phase - more solar/power than I am using. So what if it is bled off as heat vs shuttled into another cell. (My opinion- not worth much more than $.02).

 

[timselectric]

Is active balancing more efficient, yes.
Is it critical, no. Balancing current is more important to me.
That said......
Once I have my large battery bank, completed.
I want to avoid any heat being generated. As it will add up, with a large bank. Or, maybe not.
Won't know until I'm finished.

 

[Zwy]

That sounds interesting. Which model Batrium should I be looking at?
Their website for the Watchmon Core says "Advisory: BlockMons availability will be on a by-request basis starting August 2022. Recommend to switch to CellMate-K9."

For 16S, you need a Watchmon Core and a K9.

With 32 cells you can go 2P16S, personally I prefer 16S and a K9 for each.

Don't worry about Blockmons, those are a thing of the past with the introduction of the K9.

You will need some type of shunt trip breaker for critical faults needing to shut the system down. I have a ABB Sace S5N with shunt trip. The Batrium senses a critical fault and trips the breaker. Very flexible system, you can add expansion boards to control fans, PV input shutdown, alarms, whatever you want.

@Zwy and @Rocketman , what about the fact that the Batrium (I assume) uses passive balancing vs active with the JK-BMS? Isn't that a major downside?

From their webpage:

Balancing Power​

Cellmate-K9 is fabricated with 4 Ohm resistors to suit LiFePO4, Lithium-Ion or custom chemistry. This results in an Auto-Level (balancing) function of approximately 500mA achieving more than 6 Ah/day balancing adjustment for each cell.

The system operates in a four-cycle sequence of 5-second intervals. This allows for approximately 50% duty cycle between adjected cells in series to not impact cell voltage sensing or exceed wiring or fuse ratings.

When balancing is required, the four stages are as follows ODDS, EVENS, resting, then sensing and repeat. Ensure that the balancing wires are dedicated for this function and do not share any circuit with other devices.

If you run other devices that need their own circuit, take time to consider the power of other equipment, like supervisors which should have their own cabling.

Be careful not to have shared wiring with adjacent CellMate-K9 from higher voltage series as these will impact each other.

If you need more than 6Ah per day, I'd say you need to address the balance issues of the pack.

 

[timselectric]

To get 6ah of balancing, you need to be above the threshold for 24 hours. If I'm understanding it correctly.


And is that 6ah per cell, or for the entire pack?
Nvm, found that answer.

 

[Zwy]

To get 6ah of balancing, you need to be above the threshold for 24 hours. If I'm understanding it correctly.


And is that 6ah per cell, or for the entire pack?
Nvm, found that answer.

Per cell.

It's in the chart, under Daily Balancing.

 

[Nobodybusiness]

@Zwy and @Rocketman , what about the fact that the Batrium (I assume) uses passive balancing vs active with the JK-BMS? Isn't that a major downside?

This might sound weird but I use JBD to manage the battery. Since my equipment is about 300 feet away I use Batrium to monitor the cells via network.
You can also add a Heltech active balancer to each one also.
Not had any issues yet.

Use these to connect each cell to each BMS/monitor..