powering ESP32 with a battery
Posted: Sat Mar 23, 2019 11:26 pm
I've got some use cases that require the ESP32 to hibernate most of the time in very-low-power mode running on a battery. Ideally the battery would last quite some time with a hibernation power draw of only ~15uA. Can anyone recommend some options for a good cheap rechargeable battery?
I was hoping to use a single rechargeable battery that delivers a voltage which falls within the recommended ESP32 range. The datasheet states ; "The operating voltage of ESP32 ranges from 2.3 V to 3.6 V. When using a single-power supply, the recommended voltage of the power supply is 3.3 V, and its recommended output current is 500 mA or more." (but in practice I find that the ESP32 almost always draws well under 200mA).
Lipo batteries are great, but they put out 3.7 volts and require an even higher voltage for charging. With Lipo I would have to use a regulator to step the voltage down to the appropriate level. This is doable but inconvenient, and the regulators I am seeing have a leakage current that is far above the 15uA drawn by the ESP32. A battery would last only days instead of weeks or months.
I've been experimenting with LiFePo4 batteries. They can come in an AA form factor that fits into cheap, standard battery holders and they produce 3.2V. No regulator necessary. Supposedly rechargeable, but unfortunately the ones I am getting do not seem to recharge properly.
Any suggestions? Are there regulators that have very low leakage? Some other battery alternative?
I was hoping to use a single rechargeable battery that delivers a voltage which falls within the recommended ESP32 range. The datasheet states ; "The operating voltage of ESP32 ranges from 2.3 V to 3.6 V. When using a single-power supply, the recommended voltage of the power supply is 3.3 V, and its recommended output current is 500 mA or more." (but in practice I find that the ESP32 almost always draws well under 200mA).
Lipo batteries are great, but they put out 3.7 volts and require an even higher voltage for charging. With Lipo I would have to use a regulator to step the voltage down to the appropriate level. This is doable but inconvenient, and the regulators I am seeing have a leakage current that is far above the 15uA drawn by the ESP32. A battery would last only days instead of weeks or months.
I've been experimenting with LiFePo4 batteries. They can come in an AA form factor that fits into cheap, standard battery holders and they produce 3.2V. No regulator necessary. Supposedly rechargeable, but unfortunately the ones I am getting do not seem to recharge properly.
Any suggestions? Are there regulators that have very low leakage? Some other battery alternative?