Unfortunately things are getting more interesting: now ASUI now shows 5% drain per hour also on my new device. But this time I remember ...

...the last things I did:

Upgarde kernel: I could not mount samba drives, because I could not load the cifs.ko module. Apparently it was not compiled for the right version of the Diablo Turbo kernel. So I flashed the latest zImage. This fixed the problem.

Set clock with ntp: My clock was late by several hours. I changed the configuration of openntp so it adjusts the clock by any amount at startup and restarted ntp. That set the time right. Then I don't recall precisely what happened and what I did. At some point the clock was two hours in the future. I restarted ntp again and it set the time right again.

The time leap

The last incident made the device believe that time was jumping backwards. The next morning

• my originally full battery was at 40%.
• ASUI reported 5% drain/hour and
• the graph of ASUI showed the time leap by a horizontal line going from right to left followed by a steep decline

I appears that the drain started right after the time leap. I recall I had similar incidents on my old device (time off by several hours). I also recall that at some point all my alarms were gone and I had to recreate them.

So the problem is clearly a software problem and it seems to be related to Diablo Turbo and time. Does this ring any bells?