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  • The ESP32 power saving design is fine, its the board designers that let it down. For example, the light sleep current of the ESP32 itself is 20-40 microamps, however, the T-watch only manages to reduce to 2.5ma. The active current can be reduced by introducing sleep in the idle loops, but this is not currently supported in the Espruino port. However, turning on the Wifi drains the battery fairly quickly! Using it simply as a watch with on time between 5 and 30 seconds, I get about three days battery life which is OK.

  • However, turning on the Wifi drains the battery fairly quickly!

    Also turning on Bluetooth Low Energy drains the battery fairly quickly. However one guy managed more than one day with BLE 'on' by runing BLE advertising every second (yes 1 packet sent each second) Then the horrible power drain with BLE turned on averaged into something reasonable.

  • I completely agree that the ESP32 Bluetooth consumes a lot of power. I noted above that it seemed to require 40ma even if not active and so I removed it completely. This post­ues/947#issuecomment-500312453 would seem to indicate that Bluetooth on current ESP32 hardware is a lost cause as you need an external 32.768Khz crystal to get effective low-power performance (yes, it uses 1 second advertising!).

    Overall, I think the T-watch is great as it has a large bright touchscreen but it would be of much more practical use as a smartwatch if it was based on low-power Bluetooth SoC such as an NRF52840. (I have a P8 - NRF52832 - on order! )


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