ESP8266 Community Forum

- Sun Jun 04, 2017 7:55 pm #66731 hi guys, i have one 18650 battery, nominal voltage is around 3,7v and i want to use in nodemcu.
i know that apply 3,3v in 3,3_PIN it`s work, but 3,7v work or burn nodemcu? how can i supply node with JUST ONE 18650?

- Mon Jun 05, 2017 3:23 am #66740 your problem is the 4.2V of a freshly charged cell.
you need a low power low drop 3.3V regulator to get decent standby times.

forget about using the onboard regulator. It is not low dropout nor low power.
And powering the board from the Vin will also supply the usb/serial chip, adding to the standby amperage.

- Mon Jun 05, 2017 8:06 am #66745

your problem is the 4.2V of a freshly charged cell.
you need a low power low drop 3.3V regulator to get decent standby times.

forget about using the onboard regulator. It is not low dropout nor low power.
And powering the board from the Vin will also supply the usb/serial chip, adding to the standby amperage.

if i use an diode to drop 0,7v, work's?

- Mon Jun 05, 2017 10:05 am #66753 no, not realy.
looking at the datasheet of some diodes you will see that the voltage drop depends on the drawn current. Less current, less drop.
there is good reason why low dropout, low power regulators are manufactured and sold ...