Two cell lithium protection and balancing module
Added 2022-10-21 00:23:01 +0000 UTCI've never really explored cell balancing much before, so I got a simple two cell module to reverse engineer and see how it works.
It's clear that this module needs to be used with a charger that has suitable current limiting and an output voltage that matches the two cell voltage of around 8.4V.
If you have any thoughts on the notes in the video's description then let me know.
https://www.youtube.com/watch?v=kDjUQVwbmik
Comments
This is one of the simpler "passive balancing" arrangements where the balancer wastes some energy from the cell(s) which are a bit higher voltage. This allows the other cell's voltage a chance to "catch up". In most cases no intelligence is required on the part of the charger. This is a "top balancing" scheme (i.e. balancing occurs at the end of charging) and the current will already be low because you will be toward the end of the constant-voltage phase. I would think that the balancing chip trigger threshold should be lower than the outer chips overvoltage theshold. Though it may work regardless because the balancer will correct the overvoltaged cell while the back to back fets are off, and then the outer chip will untrigger and resume charging. It would take longer and not be terribly elegant but it's cheap.
Zac
2022-10-21 01:57:46 +0000 UTC
