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

[Zwy]

The way this is worded can be misinterpreted. If you have a Batrium Core and 2 K9's for each of your 16s batteries it can not shut off an individual battery bank. Your entire system will turn off if one of the battery banks triggers a fault. With two JK-BMSs only the battery bank that has the issue would be turned off so you would still have power from the other bank to power your system.

That would depend on how the system was setup, one could program the software for non critical fault and use an expansion board to trigger another shunt trip breaker if a breaker was on each battery or a parallel bank. There are multiple ways it can be done, the system is flexible and adaptable.

It's always been an argument, some prefer complete shutdown until the fault is found, others want the ability to run in a limited capacity but this might cause failure of the battery still running due to the increased load on it .

What's the answer? If one is totally dependent on their solar system, it needs redundancy where it can still handle full load. It can be accomplished several ways, however if one had a large load on a 2 battery bank with FET based BMS's and one suddenly shuts down, the increased load on the remaining battery might cause catastrophic failure in the FET based BMS.

There isn't one answer for every system, much depends on the needs of the user.

 

[kolek]

Answering my own question for the sake of anyone reading this, the JK-BMS will NOT talk to inverters apparently, according to multiple sellers of the product on Aliexpress.

 

[kolek]

Guys I think I'm going to move ahead with the JK-BMS.

So I need to manually use crimpers to put ring terminals on the end of all the JK-BMS wires, does anyone happen to know the size of lugs I should buy? I assume the unit doesn't come with them included. I guess there are 2 sizes, one for the big cables and then the 32 small wires which connect the 2 BMS to the 2 batteries.

 

[Nobodybusiness]

I have 10 batteries and I turn one off at the breaker, do any troubleshooting/repairs, make sure the battery voltage is within 0.5V of my system voltage and turn breaker back on. I could run my house on four batteries minimum. I like redundancy. I was hoping the various BMSs's would be a good idea, but most only have 0.15A bal current and have various other glitches. JK is going to be very busy.

I agree JK has a great BMS but my equipment is about 300 feet away from house.
Bluetooth doesn’t quite reach that far.
Batrium does a great job of monitoring but no so great a job of isolating individual batteries so i decided to combine the 2.

 

[timselectric]

Answering my own question for the sake of anyone reading this, the JK-BMS will NOT talk to inverters apparently, according to multiple sellers of the product on Aliexpress.

I don't use coms between the batteries and inverter, anymore. But, I'm trying to figure out if the JK can communicate with Solar Assistant. But, that could be a whole different can of worms. Especially considering that I will have 14 BMS's. lol

 

[Nobodybusiness]

I don't use coms between the batteries and inverter, anymore. But, I'm trying to figure out if the JK can communicate with Solar Assistant. But, that could be a whole different can of worms. Especially considering that I will have 14 BMS's. lol

You and I have the same # of BMS.

I have 11 DIY batteries and 4 older very heavy Global Power 400 AH batteries with absolutely no communication to anything except a small LCD voltage screen.

I haven’t used Communication between the BMS and Inverters either.

The only thing that will change that is if I convert all my DIY batteries to the Seplos DIY 280ah kit.

Then I would have the ability of 485 or Canbus.

Having said that I’m not sure what that gets me???

 

[timselectric]

You and I have the same # of BMS.

I have 11 DIY batteries and 4 older very heavy Global Power 400 AH batteries with absolutely no communication to anything except a small LCD voltage screen.

I haven’t used Communication between the BMS and Inverters either.

The only thing that will change that is if I convert all my DIY batteries to the Seplos DIY 280ah kit.

Then I would have the ability of 485 or Canbus.

Having said that I’m not sure what that gets me???

Yeah
I'm not at all interested in coms between batteries and inverter. I just think that it would be handy to look at each BMS remotely. In case I need to talk a family member through trouble shooting, in my absence.

 

[Nobodybusiness]

Yeah
I'm not at all interested in coms between batteries and inverter. I just think that it would be handy to look at each BMS remotely. In case I need to talk a family member through trouble shooting, in my absence.

True enough.

I can do that already with the Batrium..

Only reason to covert would be to eliminate so many points of failure.

 

[Shep]

Can someone explain the difference or usefulness of something like a battery monitor compared to a bms? Trying to understand why I keep seeing more gadgets popping up when the bms has so much there already..?

 

[Nobodybusiness]

Can someone explain the difference or usefulness of something like a battery monitor compared to a bms? Trying to understand why I keep seeing more gadgets popping up when the bms has so much there already..?

Technically Batrium is a BMS BUT it’s an all or nothing type deal.

If you have 176 cells divided amongst 11 x 48vdc batteries and 1 of the 176 cells decides to over charge or under volt then the Batrium only has the ability to turn off ALL the batteries via a Shunt trip breaker.
Not good unless you can trigger an ATS to push back to Utility or something.

This is why I use JK BMS to manage each battery Voltage and SOC but since my shed is so far from my house I use Batrium to monitor the cells remotely.

Most BMS do not communicate via WiFi.
If they did it would make a big difference.

Make sense?

 

[timselectric]

Can someone explain the difference or usefulness of something like a battery monitor compared to a bms? Trying to understand why I keep seeing more gadgets popping up when the bms has so much there already..?

A monitor only provides information about the battery. A BMS manages the battery.

 

[Zwy]

Technically Batrium is a BMS BUT it’s an all or nothing type deal.

Not entirely, you could set the Batrium to trip a relay on an expansion board to trip a contacter or another shunt trip breaker on a smaller system. There are several ways it can be set up, it's not all or nothing unless it is set up that way

If you have 176 cells divided amongst 11 x 48vdc batteries and 1 of the 176 cells decides to over charge or under volt then the Batrium only has the ability to turn off ALL the batteries via a Shunt trip breaker.'

I can't see running 11 batteries thru one Watchmon Core. First, it would require a separate power supply for the K9's as they only handle 6 with additional power supply. Would make more sense to have 3 Core with 4 batteries on two Core and one Core with 3 batteries.

With four 6.5K inverters running, why would you consider running all amps thru one 400A breaker? You can't, you would split the load thru several shunt trip breakers.

Not good unless you can trigger an ATS to push back to Utility or something.

If the system is properly designed, if one cell in a bank went down, the system would keep going. If there were 3 Core with 3 shunt trip breakers, if one bank went down, the other two should easily handle the load. That's also why it is split into at least 3 banks if not 4.

This is why I use JK BMS to manage each battery Voltage and SOC but since my shed is so far from my house I use Batrium to monitor the cells remotely.

Most BMS do not communicate via WiFi.
If they did it would make a big difference.

Make sense?

 

[Nobodybusiness]

Not entirely, you could set the Batrium to trip a relay on an expansion board to trip a contacter or another shunt trip breaker on a smaller system. There are several ways it can be set up, it's not all or nothing unless it is set up that way



I can't see running 11 batteries thru one Watchmon Core. First, it would require a separate power supply for the K9's as they only handle 6 with additional power supply. Would make more sense to have 3 Core with 4 batteries on two Core and one Core with 3 batteries.

With four 6.5K inverters running, why would you consider running all amps thru one 400A breaker? You can't, you would split the load thru several shunt trip breakers.



If the system is properly designed, if one cell in a bank went down, the system would keep going. If there were 3 Core with 3 shunt trip breakers, if one bank went down, the other two should easily handle the load. That's also why it is split into at least 3 banks

I don’t run 11 K9s through 1 core.

I have 4 K9s per core and the last 3 K9s.

Either way if one of the cells faults in the 64 cells of one core then all 4 of those batteries are turned off that belong to that core.
Not sure where you got 4 x 6.5 Kw inverters from. I don’t use that configuration.

All of my batteries are in Parallel and pull max 60 amps individual with a potential of 600 amps total between 2 x 12kw inverters.

Each battery has a breaker and class T fuse.

There is only one channel and 1 option to use the expansion board to trip the shunt trip breaker.

Until they can come up with a way to isolate each individual K9 with a fault then I can’t use it.

It ends up cutting off 3 perfect good batteries for no reason.

Batrium is to expensive to have core-K9/ Core-k9 / Core-k9 just so If a fault occurred it only shuts down 1 battery.

This is why Batrium is just used for monitoring and JK manages the SOC.

 

[Shep]

I've included some links of some battery monitors that are at different price points. (I know I'm invading in on this thread but I've had a really hard time getting my posts to be noticed as I start my battery system up! Sorry not sorry.)
I have 4 cells of 304ah eves that I'm just starting to understand better and out together (top balance and capacity check soon) and I wouldn't mind having a useful screen/battery monitor to help with seeing things or making my job easier (balancing the voltages or internal resistance?) It doesn't need to be dirt cheap or anything, I'm going for FUNCTION over THINGS TAKING A BIG DUMP ON ME. Not sure if that's really on the table for the overkill solar bms and Epever 30a charge controller I'll be pairing it with? But I was hoping one of you could recommend something for a 4 cell 12v 304ah pack. The Epever will have it's own screen I believe, but I'm not sure if that covers cell monitoring like what other battery monitors will do.

WonVon 400A Smart Battery Monitor - RV Battery Monitor with Shunt Support High/Low Voltage Programmable Alarm for Battery 0V-120V Support Bluetooth for 12V Lithium Sealed, Gel, Flooded Batteries https://a.co/d/3h5lJEI

SUPNOVA Battery Monitor12v 24v 36v 48v 60v 72v 84v,Car Motorcycle Golf cart Battery Meter Digital Battery Capacity 8-100V Voltage Monitor Remaining Capacity Percentage Tester with Buzzer Alarm(White) https://a.co/d/15i3LnX

And a bonus question: Are SOCs different depending on the size of each size of battery pack? Are the voltages going to change? For instance- these photos are from two different people. And the more detailed one I believe is recommending this setup for someone's 304ah 12v pack.

 

[kolek]

One problem I'm seeing with the JK-BMS is the fact that there is no power switch and some users are struggling just to get them to power on. Is there a workaround for this problem now, or has it been solved?

 

[timselectric]

One problem I'm seeing with the JK-BMS is the fact that there is no power switch and some users are struggling just to get them to power on. Is there a workaround for this problem now, or has it been solved?

Yes
The newer ones have a power switch.

 

[rhino]

For monitoring a JK BMS I simply use https://github.com/jblance/mpp-solar/tree/master/docs. It's not named very well but that repo also has a JK BMS command line util that can pull all the data from the JK BMS over bluetooth. I have it running on a Raspberry Pi 3 and configured to query the JK BMS every 60s. The Pi also runs Grafana so I can view the data however I want. Since my Pi is connected to my local network I can access the data. Here's individual cell voltages graphed for instanced that I can view from any browser:

 

[Nobodybusiness]

For monitoring a JK BMS I simply use https://github.com/jblance/mpp-solar/tree/master/docs. It's not named very well but that repo also has a JK BMS command line util that can pull all the data from the JK BMS over bluetooth. I have it running on a Raspberry Pi 3 and configured to query the JK BMS every 60s. The Pi also runs Grafana so I can view the data however I want. Since my Pi is connected to my local network I can access the data. Here's individual cell voltages graphed for instanced that I can view from any browser:

That’s very cool.

 

[Steve_S]

One problem I'm seeing with the JK-BMS is the fact that there is no power switch and some users are struggling just to get them to power on. Is there a workaround for this problem now, or has it been solved?

Now comes with switch

https://m.aliexpress.com/item/1005003104573871.html?spm=a2g0o.store_pc_groupList.8148356.2.d22d5b86jwVxPe&gatewayAdapt=Pc2Msite

New manuals and more all coming online now.

 

[ricktreat]

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?

Hey I agree with you, I think jbd is the most reliable product. And the rest are all just trying to increase your sales.