I have a Lipo (18650) which is charged by a solar panel (6V/6W + TP4056 charger). It's feeding a WeMos D1 Mini which is put in DeepSleep every 10 seconds. When it's awake, it sends something to Blynk. By connecting pin D0 to RST it works perfectly, until the voltage of the battery gets too low (< 2.8V).
The WeMos doesn't wake up at all after that. I have to manually reset the WeMos, then it works again.
I also noticed the battery doesn't get fully charged after the WeMos is 'dead'?
Sorry for my basic explanation: I'm really new to the world of ESP8266...
Thanks for your insights!
As far as I understand, the voltage regulator is automatically used by using the 5V-pin. I was using the 3.3V pin, but I changed it to the 5V pin. All is working OK for a few hours.
Andreas Spiess recommended the TP4056 charger in one of its great videos. Normally it handles the charging of the LiPo and the power of the Wemos. I'm using the TP4056 with protection, so normally it protects the battery from damage (?).
In other posts people suggest to attach the Wemos directly to the battery, while the TP4056 is handling the charging of the battery. But it wasn't clear if they are using the unprotected or protected TP4056.
I'm monitoring the battery by connecting it to the A0 pin and reading the RAW-values so I know the battery voltage. I can test it in software and if it gets too low put it in an endless deepsleep (
esp.deepsleep(0)) but this will not wake the Wemos when the battery is charged again.
Maybe this is a solution?
The SparkFun LiPo Fuel Gauge connects your battery to your project and uses a sophisticated algorithm to detect relative state of charge and direct A/D measurement of battery voltage. In other words, it tells your microcontroller how much ‘fuel’ is left in the tank. The LiPo Fuel Gauge communicates with your project over I2C and an alert pin also tells you when the charge has dropped below a certain percentage.
But again: Will this restart the ESP8266 when the battery is filled again?