Is this millet mobile power motherboard a software board or a hardware board? Why does the charging current only reach 0.7a and stop discharging when it reaches 3.5V?

Of course, this is a hardware version, which is mainly managed by the power control chip on the charging and discharging panel. Normal charging will stop at about 4.2V The charging current is determined by the control chip, and discharging to 3.5V or other voltages is also determined by the control chip to prevent the battery from being damaged by low voltage.