RE: ESP8266 Power Consumption - Further Studies

neilk — Thu, 21 Feb 2019 15:33:08 GMT

UPDATE

A more important consideration is what will happen to the actual time interval between readings if we set the sleep time to be 5 minutes? The sketch takes a finite time to execute - maybe a second or two - and yet a sleep time of 1 minute results in a time interval between readings of approximately 59.5 seconds, unless we include a correction factor. This implies that the real error in sleep time is actually greater, perhaps more than 1.5 seconds in 1 minute. So, setting the sleep time to 5 minutes could result in a much bigger error.

Modifying the sketch and setting the Witty off on another long term test which I will report on later.

A first test run of about 10 x 5 minute interval readings showed that the Witty Sleep Time was under by between 8.5 and 9 seconds per 5 minute Sleep Interval

I am running further tests to get this more accurate.

The Wemos d1 long term battery test, using the optimised sketch, has now been running for over 90 hours and and the battery voltage has fallen to just under 3.8V. This is already much much better than the original sketch

However, there is another issue to resolve - the Wemos d1 does not seem to have the same sleep time error as the Witty: with the same correction factor of 414 mSecs added to a 60 Second sleep time, the Wemos d1 is sleeping by around 300 mSecs longer than it should in every 60 second period. I will investigate this further when the long term battery test is over.

RE: ESP8266 Power Consumption - Further Studies

genebren — Sun, 17 Feb 2019 17:02:57 GMT

Good luck on getting the energy drain down to the lowest level possible. It is nice to get a nice extended time between charges. If you need really long, uninterrupted run times, you might want to consider the ability to hot swap the battery pack (with or without the boost), by having a small super cap to maintain power across the changeover.

Gene