One cell lithium battery switch control

This system implements a voltage-controlled switch designed to protect the battery from excessive discharge.
If the battery voltage drops below a minimum safe threshold, the system disconnects the load to prevent further depletion.
The load will only be reconnected once the battery voltage recovers above a maximum safe threshold.

Both the minimum and maximum thresholds are configurable, providing flexibility for different battery types and applications.
To configure the thresholds, modify platformio.ini build_flags:

-D VLOW=$VLOW -D VHIGH=$VHIGH

$VLOW is low voltage disconnect, $VHIGH is high voltage reconnect

E.g.

-D VLOW=3.1 -D VHIGH=3.82

Third version

More compact design

Second version, with periodic reset

I added a periodic reset feature in the second version, utilizing a MOSFET to briefly pull down the RESET signal of the main processor.
Firmware default is a reset each 24 hours

Schematic diagram

pcb 3d model

First version

Schematic diagram

pcb 3d model

video

first prototype video

PCB

Warning!!, this version of pcb has non-standard programming socket.
Double check pinout before programming