0 votes
asked in ESPaper by (120 points)

I just found the ESPaper project thanks to the post on the Tindie blog. In the description for the device it says:

Depending on update frequency and time required for the update the module can run several weeks or even months from a LiPo battery

To run the display for several months would be really nice but I suspect that would require an update at a maximum of once per hour. Ideally I would like to have a display that updates every minute or 5 minutes and for this to run for months, I would need a larger battery.

How large is the battery compartment in the ESPaper? What size battery have others been able to place in it?

Second question: What is the actual current usage of the ESPaper while it is in sleep mode? Also current usage while awake / updating the display / receiving data over wifi would also be useful although I imagine this varies considerably and would be harder to measure.

3 Answers

0 votes
answered by (8.9k points)
You are right, there are many factors defining the duration it can run from one charge. Battery capacity, update frequency and online duration being the most important factors. A longer 1500mAh could fit just fine in the enclosure.

About the current I'll have to do some measurements myself and can't tell you more ATM.
0 votes
answered by (2.7k points)
A typical e-paper display consumes no power after update ( 0, zilch, nought :) ).

For update again a typical display 2.5mA for 2.5seconds to completely refresh the screen and if refreshed every hour, gives a daily power consumption of 0.042mAhr.

The ESP8266 requires 75mA for 10-secs to get updated data and at an update every hour, requires 5mAhr

Therefore a 2600mA battery (e.g. 3x1.2v Nicads in series) would last for 22 days.

To change all this to 5-min updates would result in a daily demand of:

Display : 0.52mAHr
ESP8266: 60mAHr

To run it all for 1 month at a 5-min update rate would require a battery of 60.042 * 24* 30days = 43Ahr battery, or something like a car battery.
0 votes
answered by (5k points)

Not a real answer (I can't leave comments on questions) but Dani recently ran a few very interesting tests and then we tweaked the ESPaper to get a longer uptime on a single charge: https://thingpulse.com/esp8266-monitoring-power-consumption/

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