Battery discharge while Macbook was turned off in 1 week. Possible causes?
These terminal commands will show sleep/wake activity since the MacBook was last powered up.
pmset -g log | grep -e &quot;Wake from&quot; -e &quot;DarkWake&quot; -e &quot;due to&quot;
pmset -g log | egrep &quot;\b(Sleep|Wake*|DarkWake|Start)\s{2,}&quot;

They both extract  data from the power management log and produce very similar output.  Try one or other (or both). The output includes the battery charge level.
You may be surprised at the number of times the MacBook at least partially/briefly wakes whilst you thought it was firmly asleep.