I made a test this afternoon on the rooted Android in my Gemini:
- Battery 55%, 1 hour standby with lid closed --> 55% (like in zero % used)
- Battery 54%, 6 hours standby " " " without any known WiFi network around--> 44% (~ 2% per hour)
At 42% now it says « 1 day 2 hours left » and « Screen 32% and WiFi 6%. »
So, same --actually rather twice the consumption I got on Debian TP2 suspended.
Yours has something eating its battery like mad. Find out who's the culprit with a System Load that has logging.
EDIT:
I turned off WiFi when device's sleeping as listed in
https://www.oesf.org/forum/index.php?showtopic=34885- Battery 39%, 8 hour standby --> 33% (0.75% per hour), with
Computer power use: 601 mAh
Wifi computer power use: 90 mAh
This would give me 130h battery life in standby.