I have been experimenting with a soil sensor and a D1 Mini for an automated watering system. I have tried a couple of options for powering (9v battery (just because I had one handy, I know it is not the best) and a USB power tank), along with a L7805CV voltage converter and using the deep sleep mode on the D1. I managed a few days use before needing a recharge.
Solar power looks like a much better way to go but I can't get the D1 to work with a solar panel directly. I bought a couple, a 5v 0.6w and a 12v 0.6w. The 5v I have tried direct to the 5v rail and the 12v via the voltage regulator. Both fail to power the device. Does anyone know why? 0.6w and 5v should give a 120 mA current. The ESP8266 FAQ says:
"The maximum analog power (instantaneous) may be considered to be 500mA and the digital circuits may draw a peak current of around 200 mA. The normal operational current is typically around 100 mA"
Is that I just don't have enough current and my 120 mA rating is in the best possible circumstances?
I'm not bothered about the circuit being always on, just so long as it receives enough power to check in one or two readings per day. It seems that all the guides I can find use a TP4056 charging module (or similar) and a 18650 battery. I now have these on order, my question is more out of curiosity and understanding rather than trying to force it to work without a battery.
I was trying to avoid a battery because of a few pound extra cost and the fear of it getting too hot in the full sun. Would it be wise to make a vented enclosure similar to this weather station project?:
