I have been experimenting with Wemos D1 mini for deep sleep and came across the video on this topic ( Youtube Link: Wemos D1 Mini Low Power) to reduce the power consumption of the board by disabling the UART during battery operation.
As I am supplying 3.3V directly to the Wemos, after removing the copper trace as shown in the video (so that CH340 does not get 3.3V during normal operation via battery, but it gets its 5V supply when connected to the USB for programming), everything should be normal and wemos should have a better power consumption.
However, the build in blue LED on the ESP12-F is lit dimly during the deep sleep mode and I am afraid that it might eat up quite a lot of current. I do not have the possibility to measure the current at the moment, but I assume the GPIO2 has some leakage currents and/or it is pulled down during the deep sleep, which cause the LED to turn off (which does not fit totally, as the GPIO 0 and 2 of ESP8266 shall be pulled up internally for booting up).
Or the suspicion is that, the removed trace causes the CH340 UART chip behave weirdly and having some floating outputs, causing the LED lit dimly, which is supported by the interesting observation, when USB is connected to supply power to the CH340, the LED is turned off.
Does anyone have an idea, what the reason could be and how the dimly lit LED can be turned off during the deep sleep? What am I missing here?