Thank you very much!

True, this is honestly why i stopped electric builds years ago

bro have you tested your circuit please tell me it'll be a great help

So the reference pin of tl431 must be between R1 and R2 resistor?

Yeah bro, I also saw there is a mistake, after i fix that issue it almost works fine, but i recommend others to use 22k and 1k resistors for that voltage divider connected to tl 431 ref pin cause the ref input voltage is higher when you use two of 20k resistors.

I also found that out after struggling setting the TL431. Good observation

Hi, would you be so kind as to share the corrected plan, with the values of each component, thanks

Thank you! I will take a look over other circuits as well!

This is the CHARGING "half" of a BMS. This does not have the LOAD "half" of a BMS ( load over-current & under-voltage ). He made that very clear at the beginning of the video.

Look at Adam Welch's channel ukposts.infovideos and search for 'diyBMS'.

right

But they all charge to 4.2v, which is sub-optimal for battery life. This circuit is great for battery packs you don’t use much, and would otherwise just zero out eventually

Great Idea ! Or use a Buck Converter with adjustable voltage and current regulation built-in

Can you elaborate on this?

@@SocialPerspective101 on what? I don't think links are accepted in YT comments (unless they're made to your own video) ... but I can try if you tell me which part you want me to elaborate on.

@@VrumsAdventures current limiter will be > 2 orders magnitude... I did not get this part

@@SocialPerspective101 I believe it's easier to try and link you to the application. The LM317 datasheet has at chapter 9.3.6 the battery charger application I am talking about. There's the voltage divider that sets the CV part and the series current limiting resistor (Rs) that will set the max value for the charging current to your CC desired value. The CC part will not really be CC, but the current being drawn will not drop significantly during this time (it will drop with (Vbat - 1.25)/R1 and Vbat increases as the battery is charged). The CV part will stop the battery voltage from rising above the desired (usually 4.2V) value. Rs is more than 2 orders of magnitude (or 100 times) less than R1 or R2... and as such it will not significantly decrease the desired output voltage set by the divider (R1 and R2). If it's close to R1 and R2 than you're either limiting the current a lot or wasting it through the voltage divider... or both and you're setting yourself up for a hard calculation and less than optimal result. I hope this is more clear :)