Achilles heel: Battery life

Hey folks, I have a PinePhone Beta (running Manjaro + Phosh). Overall very happy with the phone, but battery life is really disappointing.

My PinePhone barely survives 3-4 hours in (mostly) passive mode. To be fair: I have a SIM-card with real IP and I am running both an XMPP server and a HTTP server on it (although they consume very little bandwidth).

Anyone tried to measure what services/devices eat most of the power? I personally have noticed, that Firefox consumes so much power, that even when I am charging the phone, the percentage won't go up.

Would appreciate very much if you share your experience and/or links.