Tinkermax shows us how he reduce the current consumption of his v2 NodeMCU in deep sleep to < 50μA:
Unfortunately, with all this added convenience comes the drawback of added power consumption, which continues even when the ESP8266 is in deep sleep.
I measured 18mA to the NodeMCU board while the ESP8266 was in deep sleep mode – orders of magnitude more power hungry than I was looking for.
So for my project (which I will write up for my next blog post) I sought to retain the convenience of using the NodeMCU, but to address its power consumption shortcomings to allow battery operation.
Read further to hear what I did.
Full details at Tinkermax’ blog.
Low power is always challenging! Good article, you might be interested on this board, designed from scratch to run at low-power: https://bitbucket.org/talk2/whisper-node-avr/overview
Cheers
I hate those 1117 LDOs, always spoils selecting modules for battery powered projects that need to sleep for a long time. The USB UART is troubling, I’d like to see that solved…
Add a modern LDO with <2uA quiescent for the Li-ion battery, then a PFET load switch and sleep current can be done at 5uA, no problem at all.
Uh, sorry, the above opinion is only true if the NodeMCU module is running as a slave module.
All stuff I’ve seen say the ESP8266 resets upon waking from deep sleep, so there’s really no point to have a 50 or 100uA load doing nothing when it can be reduced to a few uA with a separate MCU in control.
The LDO problem is so easy to solve by choosing the right battery. LiFePO4 (lithium iron phosphate) batteries have a nominal voltage of 3.2 V and don’t go over 3.6 V when charging. They work beautifully without any voltage regulator for most “3.3 V” systems such as the ESP8266.
I sell a USB chargeable LiFePO4 module on Tindie that makes it really easy to play with these batteries: https://www.tindie.com/products/xorbit/lifepo4weredusb/
Yeah, incidentally I do have LiFePO4 14500 cells and have used them in my projects, only thing to remember is to make your project scream for help when the battery goes under 3.15V thereabouts (depending on load) because after that it will die very fast…
These days it’s not available locally (for me) and I can’t get them shipped from overseas legally (okay, from FastTech…), it’s a problem with many countries. Shipping and courier restrictions are always in flux… It’s probably easier for many folks to source a Li-polymer pack locally.
Still need to desolder the 1117, oh how I hate those 1117s…