ESP8266 Community Forum

Hello guys,

I want to measure temperature and humidity (with DHT11 / DHT22) and send that data to my server. The main request is the low price of the overall project.

The main problem here is that i don't have a power line in the places i want to measure, so i need to run the ESP module with some kind of battery.

Question 1: Is the ESP the right choice to send data, when powered by a battery?
Question 2: Wich ESP module should i use? The basic ESP8266-01, the NodeMCU or even the Wemos d1 mini?
Question 3: Is there any topic where i can find some dates about this?

Thanks for the help guys.

I ran a Nodemcu with a 1800mAh battery and with tests sending a measurement every 15 min it lasted 8.5hrs - on all the time. Using a deep sleep cycle and waking for 2 min to receive a request and send a signal it lasted 28hrs. If I was not using a pi it would have lasted longer; see below.

With a 2500mAh battery and solar panel it was still going after 46hrs. I took it down as I was having some problems with the pi locking up so the Nodemcu was not going into deep sleep. I am trying to change the code but might give up as having lots of problems and will just put up with the pi sleeping/locking up.

Out of interest I have tried three sensors:
DHT22 - gave up with as it only lasted a week or so in testing using mains power then failed.
SHT15 - better but did not last as long as the BME280 and was the most expensive.
BME280 - cheapest and seemed to use the least power and has a pressure sensor as long as you buy the correct one.

There are lots of posts on here about battery use, you should just search. Too numerous and cumbersome to summarise here in one post. The 'guy with the swiss accent' has various stuff on youtube also.

in short: NO
NodeMcu boards suffer from bad deepsleep current draw caused by voltage regulator, usb-serial converter and reset/flash circuitry.