ESP8266 Sleeping

How to Run Your ESP8266 for Years on a Battery

Maybe not relevant, but this article seems to add to Eyal’s work in this area

Owen

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Interesting, but incomplete - active esp power is not included.

A 2500mAh Li-Ion @3.7v (ideally) holds 9.25Wh.
Consuming 77uA will drain it in

    battery capacity 2500mAh
    esp sleeping     0.077mA
    running time     2500mAh/0.077mA = 32500h = 3.7 years

However, we should add a transmission every 10 minutes. My best so far was doing one using 55mAs (includes reading a ds18b20 which is minor). This more than doubles the energy budget.

    esp uses 55mAs/10m = 330mAs/h = 0.092mAh an hour
    total esp usage 0.077mAh(idle) + 0.092mAh(active) = 0.17mAh an hour
    2500mAh/0.17mA = 14700h = 1.7 years

This is all ideal, 100% efficient power conversion and 100% power efficiency of the battery over the years.
Naturally, other devices which most projects will use are not budgeted. And a weak wifi connection will draw significantly more power.

  • I measured the esp-12 as low as 20uA @3.3v in deep sleep (not 77uA).
  • I use 3400mAh batteries, but they do not deliver this full capacity at the required voltage.
  • One should not run the esp off the battery directly as it will use much more initially (at over 4v it uses 500uA plus). I use an efficient 3.3v LDO.
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Found this free book on esp8266.

No idea if its any good, but downloading now.

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