ESP8266 Community Forum

- Wed Dec 13, 2017 8:07 pm #72492 More than a bit confused. I have a esp8266-12E (I think) - just the wifi chip, w 22 solder points, no pins, usb etc. I've read the posts on "run your 8266 for a year on a battery".
I built a jig for programming and testing and that's working fine. Next I wired up 2 button battery holders, (6.4v) a 3.3v reg with (+) & (-) posts. I then wired my proto pin board with the proper PUs & PD & vcc/gnd. When I powered up using 2 2032's the led flashed and my batteries died. My 3.3v, no my 2.9v, no my 2.3v, no my 1.9v.......and my batteries are now down to 1.5v. Disconnected and batteries have recovered to 5.0v.

My code: (init) blink, connect to wifi, blink-blink, send a txt msg, blink-x3, deepsleep (-1). (loop){}

Powered via a usb it works all day long. My 3D holder was expensive $0.25. Local library has 6 3d printers, a laser cutter (18"x14" bed), a computer controlled router. No charge for the equipment, filament is $.05/gram. Anyhow what am I doing wrong? Thanks

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- Wed Dec 13, 2017 9:26 pm #72493 Those batteries do not have enough peak capacity. The ESP8266 can draw 300mA or more at and if you can't supply that then the voltage will drop and crash the CPU. You can try putting a large capacitor across the supply, but that might only help a little. (although that would be desirable even with a better battery.

Use a battery that is more appropriate and then work on making your code as power efficient as possible.

Last edited by rudy on Wed Dec 13, 2017 9:33 pm, edited 1 time in total.

- Wed Dec 13, 2017 9:26 pm #72494 Well, wherever you read that you can power an esp8266 from a 'battery' for 'a year' is completely bu11sh1t.
Of course, you also should quantity what 'battery' means - a car battery is not the same as a cr2032, as it comes down to capacity!
I recently read some experiments where an esp8266 coming out of deep sleep 4 times an hour for 10 seconds each time, gave about 2 months use on 2 regular niCd AA batteries (as an example) - these figures will vary of course depending on other factors*. Cr2032's are woefully inadequate. An esp8266 will consume somewhere between 35mA and 320mA** instantaneous current, so if it was always using 40mA with no sleep, a Li-Ion 2000mAH 18650 battery would last 500 hours, or 21 days (yes days!, and that's using an 18650). And that's the best you'd get given I used a low current usage value for the example : wi-fi tx/rx uses much much more current.

* Other factors : This obviously doesn't include any other consumers such as voltage regulators or sensors, usb converter chips etc. And of course my memory is not 100% reliable either!!

** viewtopic.php?f=13&t=3875 Gives a good analysis of current use.

So as you can see a 18650 has no chance of running always-on for even a month so a cr2032 will of course be practically useless (which you demonstrate).

- Thu Dec 14, 2017 4:34 pm #72502 https://www.youtube.com/watch?v=IYuYTfO6iOs

https://www.youtube.com/watch?v=heD1zw3bMhw