Batrium: 2 Banks 1 BMS ?

Crimp Daddy

Crimp Daddy

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I plan on having two battery banks (Bank A and B) which have the capability to be run in parallel for maximum capacity. But I also want to have the ability to isolate Bank A or B without having to take down the entire system for maintenance or other reasons.

Questions:

Can the Bartium system be setup to accommodate 2 banks. If yes, can I have 2 shunts?

If I was to isolate Bank A, and the differential voltage started to increase between A and B, does the Bank with the higher voltage start to balance?

Last question, can I have more than 1 longmon per series string? I suspect I might need more than 1 longmon to take care of a 320Ah pack.
 
I think the current version can only handle 1 shunt.
You can make for isolations by using the relays to turn on/off contactors to disconnect a particular bank.
Longmons are per pack, not per series. So for a 14s string (48V nominal) you'd have 14 longmons.

I'm sure daromer will answer with more details later. ;)
 
Perhaps it was just the way I was explaining it because I need to wire each cell from each series string in parallel.

Remember, I am using EV cells which are formatted into a 5s module. 3 modules = 15s pack


image_ugmwwp.jpg


If I have 10 packs (1 pack = 3 modules)that I intend on splitting into two Banks of 5 packs, that would require 150longmons in total if I don't wire each cell in parallel which would really easy to do because I have excellent access to the balance lead tabs of each cell.

So if I wire all the cells in parallel, I was hoping to cut down on the number of longmons required. Perhaps 2 per parallel connection per bank... I could always add more if needed but to be honest I would prefer to see if I can get away with less than 2.

Not really sure how flexible the BMS would be, but not being able to have 2 shunts is answering some questions already.
 
I'm not sure if Jaron is working/planning on multiple shunts in the future. Might be a good idea to find that out first if you really need multiple ones.
 
I can probably live without the 2nd shunt... or wire it in a way where I don't worry about the individual banks. I can always add a separate Victron shunt for State of Charge so really its not that big of a deal.

I still need to figure out the longmon situation... To simplify my question: Can you have more than 1 longmon per pack?
 
CrimpDaddy said:
I can probably live without the 2nd shunt... or wire it in a way where I don't worry about the individual banks. I can always add a separate Victron shunt for State of Charge so really its not that big of a deal.

I still need to figure out the longmon situation... To simplify my question: Can you have more than 1 longmon per pack?
Click to expand...

You sure can, but not needed i thinks - if the longmonsare accurate to 0.01v then one might turn on while other is off - if you have ocd that really messes with your brain!
 
hbpowerwall said:
CrimpDaddy said:
I can probably live without the 2nd shunt... or wire it in a way where I don't worry about the individual banks. I can always add a separate Victron shunt for State of Charge so really its not that big of a deal.

I still need to figure out the longmon situation... To simplify my question: Can you have more than 1 longmon per pack?
Click to expand...

You sure can, but not needed i thinks - if the longmonsare accurate to 0.01v then one might turn on while other is off - if you have ocd that really messes with your brain!
Click to expand...

That would most likelyirritate me as I do have some OCD... like the good kind haha, but its still probably better than the pack going out of balance.

I think its worth mentioning that one "pack" for me is about 320Ah each if I split it into two banks, or 640Ah if I only make one. I believe that is 3 times larger than what Batrium recommends per pack.

I guess it is all going to come down to how close each one of these cells are matched to one another.
 
You cannot have 2 shunts in current version. You cannot have 2 separate systems on 1 Watchmon/master if you plan on using autolevel function since it will consider the whole chain and that will/can cause very odd behavior.

With that said there is work around and you potentially can have 2 banks totally sploit but you need to beware of the limitations.

If both those packs are in parallel in the end to the same input/output there is no problem. I have many of them.

Batrium max recommended is 400Ah per longmon. You can run 640 but it takes somewhat longer time to balance. You can also hook up 2 longmon per pack and double the balancing current. You can also as I said have 2 strings in parallel of 320Ah per string and 1 longmon per battery.

If you really consider having them as totally separated systems not hooked together at all consider 2 watchmons!
 
daromer said:
You cannot have 2 shunts in current version. You cannot have 2 separate systems on 1 Watchmon/master if you plan on using autolevel function since it will consider the whole chain and that will/can cause very odd behavior.

With that said there is work around and you potentially can have 2 banks totally sploit but you need to beware of the limitations.

If both those packs are in parallel in the end to the same input/output there is no problem. I have many of them.

Batrium max recommended is 400Ah per longmon. You can run 640 but it takes somewhat longer time to balance. You can also hook up 2 longmon per pack and double the balancing current. You can also as I said have 2 strings in parallel of 320Ah per string and 1 longmon per battery.

If you really consider having them as totally separated systems not hooked together at all consider 2 watchmons!
Click to expand...

I think those packs are in 5s. So I think you would need to have 1 longmon per cell (5 per pack for a total of 50 longmonsfor 10 packs). Each pack/block is 18.5v (5 3.7v cells in series). I think the long mons can do 2.2v - 5.4v.

Unless you are planning on dissassembling them to configure them a different direction.

I'm a newbie here, so I could be missing something.
 
You are on track for the most part about the packs, they are 5s each, but I plan to add 2 more in series for a total of 15s.

I think its important to note that my plan was to make parallel connections to each cell in each pack. The goal was to ultimately reduce the longmon count. Electrically Cell 1 in each pack would be connected to each other.

Its really no different than what everyone else is doing, I just have a different wiring challenge.

Note the connections in ORANGE = Parallel connection to each cell in each pack. GREEN = BMS/Longmon connection


image_kvoygy.jpg
 
CrimpDaddy said:
You are on track for the most part about the packs, they are 5s each, but I plan to add 2 more in series for a total of 15s.

I think its important to note that my plan was to make parallel connections to each cell in each pack. The goal was to ultimately reduce the longmon count. Electrically Cell 1 in each pack would be connected to each other.

Its really no different than what everyone else is doing, I just have a different wiring challenge.

Note the connections in ORANGE = Parallel connection to each cell in each pack. GREEN = BMS/Longmon connection


image_kvoygy.jpg
Click to expand...

Thanks, I have the same modules and am going to be tackling the same issue when I assemble with a BMS.
 
Awesome, how many kWh in cells do you have? Most of mine are all 5s, but I do have some 6s modules which I am using for something else.
 
CrimpDaddy said:
Awesome, how many kWh in cells do you have? Most of mine are all 5s, but I do have some 6s modules which I am using for something else.
Click to expand...

Currently have about 33 kwh, getting another 10, so that should put me at about 43 kwh. Planning on building an offgrid house. I'll have propane or natural gas for heat/cooking/drying.

Got most of it for about 100-130 per kwh.

I'm going to use the magnum 4448inverters, and probably use their other components for charge controllers/load centers. Plus about 5-8kw of solar.
 
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