Does the ESPaper enclosure have enough room for a battery larger 800mAh? What is the power usage during sleep mode?

Question

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.

Answer 1

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.

Answer 2

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.

Answer 3

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/