I guess I’ll do @b264 's job for him:
https://forum.esk8.news/t/beautiful-diagrams-no-words-serious/15208/8?u=chr1spe
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thanks you
just to double check I do ALL the bms stuff after I fully wire all my series connections?
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You can do it before hand as long as you keep all the groups in the correct order, don’t plug in the BMS until it’s fully done and make all your series connections properly
He’s due for some maintenance. His humor module is clearly broken and needs to be replaced.
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Lol
For my own pack, I’m just gonna monitor it until it’s unacceptable and replace the group at that point
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Group 11 is the lowest, so of course it’s not balancing.
The way “balancing” works on a BMS is that it drains down the highest cells, until they match the lower cells. Since group 11 is the lowest, why would the BMS want to drain it down further? Its whole goal is to drain all the others down to 4.074v to match that one.
The BMS has no way to add charge back into an individual group, it can only remove charge by disippating it as heat…
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Well yeah I get that, and I’ve been watching the other cells bleed off and balance while connected to the charger, but I don’t see group 11 raising while the bleeding is happening. Do I need to change the BMS settings or drain some of the pack charge to get the current to go where it needs to?
It won’t. The BMS has no way to add charge to a single cell. It will bring ALL the other cells DOWN to the lowest one. Once they all match, they will all charge evenly.
Some BMSs will keep cycling the charge fets on and off while the balancing happens, as one cell or another is brought low enough for the whole pack to charge up some more, but this doesn’t help or speed up the balancing process at all really.
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So just let it sit? Let it do it’s thing?
Yup. It’ll take a while, but eventually it should all end up even and fully charged.
Then you get to drain it, and keep an eye on the individual cell voltages - if one group starts dropping faster than the others, STOP and fix that group. That’s your first sign of more bad welds.
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*Passive BMS, active do.
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Very true.
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What’s a good starting point on shopping for an active BMS that I can run in direct discharge and has telemetry?
they are 4 times the price of an LLT though…
Not sure where to get one with an app though, but I think you’ll find one.
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Looks pretty good to me
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Nice!
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