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Master Slave BMS Specs Feedback welcome!

5722 Views 12 Replies 4 Participants Last post by  annerajb

Wanted to share what we been working for the past year or two and gather some more feedback about. (I already got some see below)

We decided after Hurricane Maria in Puerto Rico to allow our aircraft BMS we designed to be used for diy powerwalls and HV conversion packs.

Here is a link to the post with the specs.

It should also work with 24v and 48v packs using 6s and 12s packs same way Tesla does it.

In terms of pricing and delivery this is our price targets:

BMS(master board) $120 USD
BMB(slave board) $98 USD each (up to 6 cells each 24v ) some sort of volume discount if more than one is needed. (includes thermistors)
Shunt $100 USD

Any feedback on it? Especially regarding connectivity and outputs?
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If I read the specs correctly, the slave boards are supplied independently by 12V power. I like this. No parasitic draw for individual cells for the BMS slaves. I don't like the "18V to 75V" (DC?) input for the BMS master board, though, for an automotive application. If I were use this system, I'd have to get a DC-DC converter just for the BMS master. What current draw will the master board have?
We made it have a wide VIN so it would work for anything going from 12v (same power source as BMB, to 48v packs)
I'm a little confused - the specs on the page say "18V to 75V". If it can indeed operate as low as 12V then I'm happier.

Regarding the slave boards - can they bridge a service disconnect gap? In other words, if I have a service disconnect in the middle of a group of 6 cells, will there be any problem when it is disconnected? There of course would be no pack charge or discharge when the pack is broken so no need to manage the system during disconnect.

Also, how long can the battery terminal leads be? What kind of wire will you recommend? Do you do anything for de-noising of the voltage sensors?
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