From what i've read online, 3.0V is the absolute maximum li-ion and li-po batteries should be discharged and around 3.2-3.4 is preferable for preserving battery life.

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if that is the case, then why is it nearly every single 4s BMS I find stops discharging at 2.5V-3V!


Edit: I can see the potential reason to want to maximize use in a cycle as an emergency option, but I don't imagine people wanting to buy systems where this is the default and unalterable! Is there a BMS system or standard for a way for managing batteries that both manages to balance batteries and not kill them pre-maturely at the same time?


1 Answer 1


This may be for a couple of reasons.

  1. The battery voltage will sag during high current draw, if the cutoff is too high it might trip even though the battery has plenty of capacity remaining.

  2. It may be there as a last resort, and set as low as possible so you can get all the power out of your battery if you want to. 3v per cell isn't great for longevity, but the battery will probably not be damaged noticeably by one discharge to this level.

  • $\begingroup$ Is there such a thing as a BMS that cuts off at a higher level, or one that can be set to a higher level? Or is there a better type of system for preventing battery over-discharge/overcharge that's not over $100? $\endgroup$ Commented May 2, 2020 at 16:29

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