Communicating BMS's for 14s packs


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The-J-Man

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May 2, 2017
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Greetings,

Since Korishan answered on my thread about building single 14s packs to easily expand I am more and more intrigued to build this way.

But going with Batrium is stupid for this setup.
So do you guys know any 14s BMS's that can communicate with each other? So that each pack has its own BMS but they are talking to each other to keep the overall voltage correct etc..

cheers
 

daromer

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Batrium does that :)
May I ask whats stupid with batrium and wont work? That it would be alot of mons on same pack? I think most setups will be stupid in that sense when it comes to a multiple pack structure. Rec bms and others can do it but they you get a full unit for each.

Not aware of any other cheaper than batrium atleast that communicate and do what they should.

I vote for single packs or larger packs like 4s or other.
 

The-J-Man

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May 2, 2017
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daromer said:
Batrium does that :)
May I ask whats stupid with batrium and wont work? That it would be alot of mons on same pack? I think most setups will be stupid in that sense when it comes to a multiple pack structure. Rec bms and others can do it but they you get a full unit for each.

Not aware of any other cheaper than batrium atleast that communicate and do what they should.

I vote for single packs or larger packs like 4s or other.

14mons per pack sure adds up ::D

You know those 14s balance boards with like 15A you can buy? one of those that can communicate with others per pack would be great. They go for like 20 :D

Havent considered something like a 4s pack. hmmm
 

daromer

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14s boards that can balance with 15A? For 20Euro? Did you drink alot lately :D

I wanted to do 14s packs to but yes unless you do them massive batrium doesnt work so have been thinking of doing some kind of "batrium" pack that you hook up to a balance cable. But the issue is that every longmon need its own wires = 28 of em per 14s pack hehe. Big connector
 

The-J-Man

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daromer said:
14s boards that can balance with 15A? For 20Euro? Did you drink alot lately :D

I wanted to do 14s packs to but yes unless you do them massive batrium doesnt work so have been thinking of doing some kind of "batrium" pack that you hook up to a balance cable. But the issue is that every longmon need its own wires = 28 of em per 14s pack hehe. Big connector

Well ok maybe a bit more ::D
I might, every now and then....

interesting. thats a lot of cables... and then every time you add another pack you have 28 more :O Not cool.
 

daromer

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Yeah need good contacts. i have had the idea to and i still want to do it.. I just havent solved all issues with it :)
 

Korishan

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Yeah, I didnt say it was gonna be easy doing it that way ;)

That's why I said I'm working on a custom bms for it. I just haven't figured it all out yet, like daromer said. Just takes a little time.

Now, if we could use the bms chips from the laptop cells, that'd be great. But I can't find any datasheet on those because they "aren't released to the general public" as one site said.
 

mormor1971

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Sep 18, 2017
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I guess one option would be to have the longmons fitted to the shelf on the inverter side of the connector to each xS cell pack, that way when you replace a pack the longmon stays where it is and you only need 14 of them to monitor a 14S pack.

You will lose out on the temperature sensor measuring the cell pack voltage and you would get a slightly lower voltage reading on the cell pack depending on the voltage drop across the connector and the cabling on the cell pack side but if you keep those short and fat that drop should be negligible I would think.

And I too would vote for bigger packs in parallel instead of lots of strings of smaller packs. You could make a cable harness with two Anderson connectors next to each other so that you have prepared for two cell packs right from the start, that gives you a backup if you need to take one cell pack out of action as you would then have one other pack next to it for each 1S pack...
 

floydR

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Aug 23, 2017
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Korishan said:
Yeah, I didnt say it was gonna be easy doing it that way ;)

That's why I said I'm working on a custom bms for it. I just haven't figured it all out yet, like daromer said. Just takes a little time.

Now, if we could use the bms chips from the laptop cells, that'd be great. But I can't find any datasheet on those because they "aren't released to the general public" as one site said.

I know this is an old post, but I saw a site http://kuzyatech.com/testing-laptop-battery-pinout-smbus-charge-capacity
where they talk about using a TI EV2300 communication adapter to reset the laptop bms. Might be able to figure out how to use one in your custom bms
later floyd
 

Korishan

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It'd be nice, but for over $200 for the communication board, not worth. There are some boards that are being resold on eBay and such for cheaper, but with these kinds of things, you never really know what you're gonna end up with. TI EV2300/2400 board is a great board and all. But it's really designed for someone who's going to be mass producing and needs a prototype communication board. It's a bit outta my league. I'll hafta stick with the cheapo arduino, atmega, rasp pi, or something like that.
 

Korishan

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Ohh, i see, that's the smaller board. I was thinking of the other board. That one is the $200+ board.

But yes, it is still pricey for just something that communicates. Altho, you can make one, I believe. Just need to know all the commands and write it up for an arduino or other mcu.
 
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