Looking at powering an ESP32 from Li-lon batteries, specifically NCR18650B (3400mAh) I tried to build the circuit in Random Nerd Tutorial’s Power ESP32/ESP8266 with Solar Panels. There a MCP1700-3302E LDO regulator (PDF warning) is suggested, but when using the NodeMCU ESP-32S it could not start up Wi-Fi reliably. Every now and then it would work, but my guess is the 250mA limit was not quite enough to satisfy a current spike as the Wi-Fi turns on.
It could be that my particular board was deficient in some way, but I wanted more flexibility on the input voltage end of things anyways (e.g. boost when voltage is too low). When looking around, two chips stood out to me, the TPS63020 and TPS63060 (PDFs),
|Input voltage||1.8 V – 5.5 V||2.5 V – 12 V|
|Output voltage||1.2 V – 5.5 V||2.5 V – 8 V|
|Output firstname.lastname@example.org V (VIN> 2.5 V): 2A||@5 V (VIN <10 V): 2 A in Buck Mode
@5 V (VIN>4 V): 1.3 A in Boost Mode
|Quiescent current||25 μA||< 30 μA|
|Operating Temperature (°C)||-40 to 85||-40 to 85|
They don’t seem to be sold on boards particularly commonly, so I ordered a couple of whatever I could find. I ordered two boards with the TPS63020 on them (this one, for ~13.37$ CAD, and this one, for ~7.28$ CAD) and one board with the TPS63060 on it (this one, for ~5.11$ CAD).
All of them are slightly more expensive than I was hoping, but the specs are much more in line with what I wanted compared to the LDO regulator. I’d love to find a TPS63021 (the fixed 3.3 V output chip) to play with, but no luck so far.