I would like to power an ESP32 devkit board with four NiMH AA batteries.
The ESP32 board has an AMS1117 voltage regulator. It has a dropout voltage of 1V. The output voltage is 3.3 Volts so my understanding is that the minimum supply voltage is 4.3 Volts.
For 4 NiMH AA battries:
- Full: 4 x 1.4 = 5.6 Volts
- Nominal: 4 x 1.2 = 4.8 Volts
- Empty: 4 x 0.9 = 3.6 Volts
This means that the voltage regulator should stop working when each cell reaches 1.075 Volts (4.3 / 4). This voltage should be safe for the NiMH batteries, my goal is to not damage the batteries by discharging them too much, is this "protection" enough to avoid deep discharge ?
External monitoring (absence of communication) will warn the user about the low ('dead') battery so the ESP32 should not stay in this condition for long.