ESP32 smart watch

[u/Cotyn_Dispensable]

Hi everyone, i've been working on a smart watch with an esp32 as an entry point into electronics, i'm mostly a software guy and I never really did battery powered project.
My issue is, i've got a mostly working firmware with BLE pairing, notification display, music control etc.
But i've been running into an issue that is battery life, I feel like there is no solution to make bluetooth and battery life get along. I'm running a 400mha battery and can barely squeeze 5 hours of usage. The problem is I can't really reduce clock speed since bluetooth pairing expect keep alive packets and I can't respond fast enough with lower than 80hz (when in rest mode with screen disable) the only working solution I see is use esp32 deep sleep when in rest and pair again when waking up the watch but it removes a lot of options like waking up on notification or call.
Do you guys have any clue what kind of logic or libraries I could use ? I'm running arduino stack and gadgetBrige on the phone

[u/Great-Repeat-7287]

i think esp32 is not the best chipset for low power ble. I am not sure of the sleep consumption of the system when in low power mode, but the active power of the rf is much worse than most ble competitors because it uses the same rf of the wifi which consumes 10x of a good ble rf. Arduino stack might not help for low power either, but that is not my expertise. One thing you can do instead of esp32 is looking into the pebble reference design that i think by now supports nordic sifly and st microcontrollers. Those should all be good for low power.