I know for fact that many battery bank owners use them incorrectly: Using the internal battery in their UMPC first and after that connecting them to the battery bank to have it charged again. By doing this you are getting less total battery life (Battery Bank + Internal Battery) in about 16% than if you connect your battery bank to your full charged UMPC and wait until it's discharged to start using the battery from your UMPC.
I asked one of my readers at todoUMPC to run two tests: One starting to use the UMPC, once it's discharged connect it to his battery bank and once the battery bank is discharged to use again the UMPC. And here is the result: 330 minutes.
After that I asked him to run another test, using the Battery Bank until it was discharged and then use the internal battery of his UMPC, this time the total battery life was 391 minutes.
As far as I know, this is the first time these tests have been done even when many including me theoretically were recommending to use the battery bank with the UMPC full charged to get more battery life from the battery bank.
PD. is no it good to have a personal translator telling about all these interesting things that are happening at todoUMPC - the biggest forum about UMPC after OrigamiProject.com? BTW, the Second Issue of todoUMPC Magazine is coming mid March with more pages and a very interesting Interview that will be posted here in English!