Shutdown at approx. 26% battery

Hello,

My BangleJs 2 seems to power off long before it reaches 0% of the battery, after about a week or so. When I plug it back into charge, the battery begins around 25%, suggesting that the watches metrics for power use are a bit off.

It's not a huge deal, but figured I should report it, if for no other reason than to keep any eye on possible vendor related hardware issues.

Thanks!
Amos

If HughB agrees, I will quote his answer in another Thread

HughB
There's a whole thread on this a while back, I'd have to look back to find it. About a month ago.
The battery usage as shown by % is not linear. The last 40% will shoot down in 1 day. The first 60% may take 3-20 days depending on what things you have configured.

The best is to think about charging your Bangle when you approach the 35/40%

Hi,

Sorry about this - the battery power is measured using a 'potential divider' which is two resistors, but most resistors are only ~10% accurate. The battery voltage changes by about 10% between 90% charged and 10% charged, so while I try and set values that work with most watches, on some it's just not good enough.

There's a thread on this at http://forum.espruino.com/conversations/371254 and you can upload something that will fix it for your watch pretty easily if it bugs you.

I'd been hoping that I wouldn't have to do this, but it may be that I'll need to store a per-watch calibration value for the battery in the settings file... It's definitely something that can be fixed in a firmware update

The calibration might be a good idea... My watch, with my current setup, takes about 6 days to reach 50%, and then it's dead 7 hours later (actually reaches 0-ish % before shutting down).

The best is to think about charging your Bangle when you approach the 35/40%

I always treat anything below 50% as a must charge today.

When I plug it back into charge, the battery begins around 25%

I would expect this as well. If you unplug it at that point it will drop very quickly.

Hi,
I've been experiencing a slightly different issue, I do not see any real change in the battery indicator for about a week (it looks like its 100% full or not perceptibly less) but then suddenly the watch is dead and I need to plug it into a power source and it will reboot.
Any thoughts, please?

Check the link @Gordon posted in post #3. It sounds like exactly your issue...