Italian teardown translated by google.  Notice battery 190mAh
https://www.tuttoandroid.net/tag/amazfit-bip/#specifiche

Amazfit Bip Hardware

Amazfit Bip offers a complete data sheet, especially in relation to the price at which it is sold. In addition to Bluetooth 4.0 LE connectivity, which allows you to connect it to the smartwatch to synchronize the data collected and to receive notifications from the smartphone, we have an accelerometer, an electronic compass, a green light pulse detector and a GPS module.
We also find a vibration motor for alarm and notification functions and a 190 mAh battery that guarantees exceptional autonomy. If the GPS module is not used and the continuous detection of the heartbeat is not activated, it is easy to exceed the month of autonomy. The GPS module is very precise and increases the attractiveness of a product that stands out compared to the proposals of the competition.
One of the strengths of Amazfit Bip is undoubtedly the 1.28-inch screen. While not offering a particularly high resolution, equal to 176 x 176 pixels, it is perfectly visible in direct sunlight thanks to the transflective technology  At night or in dark environments the screen takes advantage of the LED backlight to ensure a good visibility.

My bip easily lasts a week in normal use.  That’s 190/7 = 27mAh / day.  It takes about 2-3 hours to charge properly.
A supercap like this has about 24mAh capacity.  Datasheet.  The charge time at 1C is 64 minutes.   At 10C it is 6 minutes, but it has to be charged at 240mA.

Six minutes is not my aspirational time,   I was hoping for ~ 1 second, but perhaps it fits into some daily routine TBD.

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