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Batrium: 2 Banks 1 BMS ?
#1
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.
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#2
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. Wink
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#3
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: bTLfQA3.jpg?1]

If I have 10 packs (1 pack = 3 modules) that I intend on splitting into two Banks of 5 packs, that would require 150 longmons 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.
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#4
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.
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#5
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?
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#6
(04-13-2018, 05:58 AM)Crimp Daddy Wrote: 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?

You sure can, but not needed i thinks - if the longmons are accurate to 0.01v then one might turn on while other is off - if you have ocd that really messes with your brain!
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#7
(04-13-2018, 06:11 AM)hbpowerwall Wrote:
(04-13-2018, 05:58 AM)Crimp Daddy Wrote: 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?

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

That would most likely irritate 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.
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#8
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!
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