Jack Douglas asked 2 years ago
I have modified this weather station to use the esp32 wifi to communicate with a Raspberry Pi instead of LoRa. As such, I have found a Li-ion 18650 battery and MCP1700 LDO do not consistently provide a reliable output voltage of 3.3V even when the battery is freshly charged. Sometimes it drops down to < 3.1v so that the esp32 wifi is not strong. I am wondering why this is the case, and what options to pursue. I am looking to use instead 4S AA NiMH batteries and NiCd NiMH Battery Charger. Any additional suggestions? thx
William Lucid answered 2 years ago
Good Evening Jack,
Prompted Google’s Bard for the typical operational temperature range of both the 18650 lithium-ion and NiMH rechargeable batteries; his response is in this Gist document:
Gist of typical battery operational temperatures
Depending on your location operational temperature range may be a factor.
MCP1700’s input voltage is limited to 6 volts; ruling out 2S, 18650 batteries. Switching to a Rohm, BA033CC0WT would give a higher LDO input voltage; however, typically operational temperature range of 18650 batteries is 32°F to 113°F. NiMH batteries typically operate in the operational temperature range -4°F to 149°F.
If you have any questions or concerns about using batteries safely, please consult the manufacturer’s documentation.
Regards,
William