Bjorn guided me to do a few experiments. So we did: 1. Changed TimeLow=12002, TimeCritical=12001, TimeAction=12000 in /etc/UPower/UPower.conf 2. Set UsePercentageForPolicy=false so that the laptop should in principle hibernate immediately (at the time it was showing about 2 hrs of battery remaining) Sure enough upowerd crashed again with all the described symptoms flaring up. Clearly not a battery issue. I am trying to get the bt now.