not about the battery life though. My understanding is that applications must be updated to make the life of the battery manager easier. But that's just guessing on past articles read here and there.

Right now, on Mobian, you will get more or less 2-3 hours of screen on time, with everything enabled (modem, wifi, bluetooth, max screen brightness and doing stuff with it

If you just let it sleep (modem on registered to the network, allowing for voice calls, all the rest of the phone suspended), you'll get about 24 hours of runtime.

I think there's still more power management fixes that can be done, mostly in BT/Wifi, but it's not bad at all for a phone that's still tagged as "dev"