Pebble - rePebble

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Why Pebble?

Always-on e-paper screen (it’s reflective rather than emissive. Sunlight readable. Glanceable. Not distracting to others like a bright wrist)
Long battery life (one less thing to charge. It’s annoying to need extra cables when traveling)
Simple and beautiful user experience around a core set of features (telling time, notifications, music control, alarms, weather, calendar, sleep/step tracking)
Buttons! (to play/pause/skip music on my phone without looking at the screen)
Hackable (apparently you can’t even write your own watchfaces for Apple Watch? That is wild. There were >16k watchfaces on the Pebble appstore!)

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infinitevalence@discuss.online

Battery % going up after charging? (lemmy.zip)

submitted 2 weeks ago* (last edited 2 weeks ago) by MrTolkinghoen@lemmy.zip to c/pebble@discuss.online

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Yesterday i charged my pebble c2d for the second time. Got the watch at 80% charged it to 100% then drained to 30% over 12 days, then charged it up to 62%.

What's weird is after charging, my reported battery kept going up even when not on the charger. It was at 74% 8 hours later. I restarted the watch and it showed 88% immediately and then has since dropped to 87%. Anyone have any idea what happened here?

Edit: Guess I can answer my own questions with some research. Love having access to the source. Older watches use a linear voltage table with some debounce logic. These new nrf based devices use Nordic's fuel gauge library with coulomb counting. So, it's an adaprive algorithm that learns over time. Only issue is calibration takes discharge cycles, but with a watch that discharges over weeks, not days, that can take a while as I'm on only my second discharge cycle, and even then not a 100% cycle. Oh pebble problems ;)

I'm guessing if i had waited for a full charge that also would have helped.

Source: src/fw/services/common/battery/nrf_fuel_guage/battery_state.c

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[–] infinitevalence@discuss.online 3 points 2 weeks ago (1 children)

So the battery % is actually calculated from the battery voltage, its possible that the reported voltage had some delay in being read and calculated.

Meaning it could look like the battery % was going up after being removed from the charger because last voltage read was delayed.

[–] MrTolkinghoen@lemmy.zip 1 points 2 weeks ago* (last edited 2 weeks ago) (1 children)

I'm using gadgetbridge, so it's just reading what the watch tells it. Shouldn't be any delays there. Also the watch ui was reporting the same with the % slowly going up.

Feels like for some reason the warch was reading the wrong value. 🤷

[–] infinitevalence@discuss.online 1 points 2 weeks ago (1 children)

That number is direct from the watch firmware, you can see it in the code.

[–] MrTolkinghoen@lemmy.zip 1 points 2 weeks ago* (last edited 2 weeks ago)

Yeah I mean what I meant is that the voltage for some reason was reading incorrectly at the hw level

[–] LodeMike@lemmy.today 2 points 2 weeks ago (1 children)

Battery % is estimated based on a voltage measurement tool across the terminals of the battery and data that is tuned to that specific battery.

Lots of things could be happening. Likely if you're not experiencing battery or petformance issues is that the measurement hardware is degrading.

[–] MrTolkinghoen@lemmy.zip 2 points 2 weeks ago

Yeah the watch is performing just fine and given that a reboot fixed it... Idk. We'll see if it happens again. But yeah sounds like something hardware related if it repeats. Doesn't really matter as long as I can accurately know when the battery is low. Esp with 12+ day battery life. Hopefully it was just a fluke.

Was mostly wondering if there was a known reason for it to happen .