With a little charging circuit this could be a nice solution. I think there should be a few nice solutions which can both charge lithium cells and convert power to 3V3 (or 5V). Also the ESP can be brought to a (programmable timed) deep sleep, power consumption then goes down to few uA (if done correctly, mind that a simple LED consumes a few mA already). I guess there should be a few integrated solutions already available for this, e.g. on Aliexpress.
For instance a LM3671 could serve as a nice voltage regulator, it is quite suited for being used with LiPo cells.
You also might have a look at Aliexpress, there are several cheap solar charging PCBs available. These circuits are all quite simple, it shouldn't be a huge problem I think
A nice video on this topic is provided by Andreas Spiess (the guy with the Swiss accent
). A must-watch if you are considering reducing ESP power consumption:
https://www.youtube.com/watch?v=IYuYTfO6iOs
For instance a LM3671 could serve as a nice voltage regulator, it is quite suited for being used with LiPo cells.
You also might have a look at Aliexpress, there are several cheap solar charging PCBs available. These circuits are all quite simple, it shouldn't be a huge problem I think
A nice video on this topic is provided by Andreas Spiess (the guy with the Swiss accent
). A must-watch if you are considering reducing ESP power consumption:https://www.youtube.com/watch?v=IYuYTfO6iOs