ESP8266 Community Forum

- Sat May 13, 2017 5:56 pm #65904 Hey all,

I'm fairly new to esp8266 and arduino in general. I bought a starter pack and a few other things, including an esp8266-01. On learning it alone can perform I've focused on tinkering just on it. So far so good, however yesterday I figured to test how long it lasts on an enormous looking 9800mA 18650 battery. I was shocked that it appears to have dropped offline in less than 12 hours! Does that power usage sound normal or excessive?

I'd envisaged powering one by an 18650 battery and a small solar panel, however now I wonder if that would be adequate? The sketch I was running on it seemed fairly innocuous, though I suppose it would have contributed. It simply listened for an mqtt signal and responded with the getVcc and RSSI values on other mqtt topics.

Am I (I assume) missing something blindingly obvious?

- Mon May 15, 2017 2:17 pm #65953

I'm fairly new to esp8266 and arduino in general. I bought a starter pack and a few other things, including an esp8266-01. On learning it alone can perform I've focused on tinkering just on it.

The ESP-01 is not the best module to start with, as it can't do deep sleep without hardware modification (which involves soldering wires to 0.25mm pads) and has only 2 I/O pins, both of which need to be pulled high on startup (so the are ill-suited as inputs).
I would rather recommend getting a "Wemos D1 mini" (they even have a shield for using LiIon/LiPo batteries), as it is much easier for beginners to use.

So far so good, however yesterday I figured to test how long it lasts on an enormous looking 9800mA 18650 battery.

That battery is definitely a fake, if you're lucky it holds 1/10th of the advertised power, just do a web search for "fake 18650" or similar.
18650 batteries with 9800mAh simply do not exist, the highest capacity ones you can get are around 3400mAh (e.g. Panasonic NCR18650B).
You may consider using phone batteries instead, as they are widely available, usually cheaper and come in a wide variaty of sizes/capacities.

I was shocked that it appears to have dropped offline in less than 12 hours! Does that power usage sound normal or excessive?

Without using any power saving modes, the average current draw is usually in the 60-70mA range.
For battery powered applications you should at least use light sleep or better yet deep sleep (see documents section on the espressif website for details).

- Tue May 16, 2017 3:50 pm #65987 Ok thanks, I'll look into the Wemos D1 mini. Hopefully it's as small and cheap as the esp waa (from memory about $3).

I assumed I'd need to periodically sleep whatever unit to stretch a battery. Hopefully sleeping for 5 seconds at a time or so would still leave it appearing live enough to query via mqtt.

Re the battery options, if I just connect the solar panel directly to the battery, and also the esp or whatever,, would that work? What I like about the current 18650 I have is that it's case has some small board in it that makes it easy to plug a board and solar panel into it via USB, then I can step down the power to the board.