search

endico / PurpleAir-for-MagTag

A PurpleAir Dashboard For MagTag
12 stars 3 forks source link

When should the "Battery Low" warning appear? #1

Closed endico closed 3 years ago

endico commented 3 years ago

Ideally it would be nice to have the battery warning appear maybe 12 hours before the MagTag dies due to low power. That should give plenty of time to notice the problem and recharge the MagTag.

I originally had the warning appear when the battery reached 3.8 volts but that guess is way too high. I think the MagTag has lasted a week so far since the warning appeared. I have a battery testing script running and 3.3 is about the point where the battery drain accelerates so I'll set it there for now but I may lower it some more later when testing is complete.

https://io.adafruit.com/endico/feeds/battery https://github.com/endico/Magtag-Battery-Test

endico commented 3 years ago

The battery I'm using is the 3.7v 420mAh Lithium Ion Battery https://www.adafruit.com/product/4236

endico commented 3 years ago

I guess 3.3 Volts is good enough. In my battery test script the battery ran out about 8 hours after it hit 3.3 volts.

endico commented 3 years ago

I'm going to leave it so the battery low warning is displayed at 3.3 volts. I've realized that it doesn't matter if I'm warned of a low battery in time to recharge it since I rarely noticed the message in the 8 hours before the battery dies. All that matters is that the screen says 'Low Battery' when the battery is dead.