Battery Model?

[RKBoss6]

Since the Bangle.js battery percentage is voltage-based, it's not exactly linear in percentage display. By comparing it to the manufacturer's provided discharge curve, we can get a linear percentage, and it's something I want to try working on to make the default percentages more reliable. To do this, I need the model of battery used so I can see if the manufacturer has a data sheet for the battery.

Thanks!
Edit: This is for bangle.js 2 btw

[gfwilliams]

https://www.espruino.com/Bangle.js2+Technical

XK302627

That really won't help you though. We already do apply a curve correction based on real-life data of Bangle.js battery discharge - you could attempt to change that but I think it's pretty good.

If anything what's needed is correction for temperature as well, but it'd be very easy to make the situation worse rather than better as you're talking 1% difference in battery voltage at times.

[RKBoss6]

Hmm, how would I go about adding temp correction? For me it seems like the battery drains slowly from 95% to 70%, then drains much quicker until 15%, which then drains extremely slowly, and this can mess up readings from apps that use average battery drain tracking...

[gfwilliams]

Well, first, I'd ensure the Bangle is fully charged (leave it all night on charge), then go to settings->utils->calibrate battery - that might really improve matters for you.

But if that doesn't work, maybe set up some code that does analogRead(D3) a few times to get an average, and does it every minute. Then have something that draws a modest amount of power (maybe turn the LCD backlight on) and then leave the Bangle logging for the ~10 hours it'll take to run the battery down.

So then you can get a graph of the actual discharge over time - then you can update this code based on what you see: https://github.com/espruino/Espruino/blob/master/libs/banglejs/jswrap_bangle.c#L3015-L3020

[RKBoss6]

Alright, thanks! I'll report back here once I have any updates!