I'm trying to power my ESP32 Wroom 32e devkit C using Lipo batteries. I know that the 5v or VIN pin goes through a voltage regulator but the 3v3 pin doesn't. The thing is, Lipo drone batteries can sometimes go up to 4.2v which will definitely fry the board but it's not enough for the regulator. Using two batteries in series into VIN would work, but then I can't charge them unless I take them out.
I was thinking of using low dropout voltage regulators like mcp1700 on the 3v3 pin and using the same regulator on a C-type port for charging.
For common LiPo batteries, the nominal or average voltage is 3.7 V/cell with a maximum voltage of 4.2 V/cell. After the cell is fully charged, it will briefly provide 4.2 V before dropping to 3.7 V for most of the battery life. It becomes dangerous to discharge the battery after the cell voltage has dropped below 3.2 V .
SO the cell voltage should always lie between 4.2V and 3.7V and your LDO would work.
The safest way to charge a lipo battery and the one that puts the least amount of strain on your battery is to charge at a rate of "1C" or 1 times capacity. A 1C charge rate means that the current will charge the entire battery in 1 hour
You will need more than a simple LDO regulator to manage that safely.
Using a low dropout voltage regulator like the MCP1700 to power your ESP32 via the 3.3V pin is a feasible approach to regulate the voltage from a LiPo battery. This allows you to directly use the LiPo's voltage, even if it's slightly above 3.3V. However, you need to ensure the regulator can handle the maximum voltage of your LiPo battery (around 4.2V when fully charged) without getting damaged.
For charging, using a C-type port with the same regulator is a good idea, as it simplifies the charging process. You'll need a suitable LiPo charging circuit that regulates the voltage and current for safe charging.
Just make sure that the regulator and charging circuit you choose can handle the required current for your ESP32 and are properly configured to prevent overcharging or over-discharging the LiPo batteries. Also, consider implementing protection circuits for the LiPo batteries to ensure their long-term health and safety.