Yeah, obviously. Some time ago I bought a WeTab portable computer and the machine is wonderful. I can (and I actually do) use it in any way imaginable: it’s a tablet form factor (so it’s my heavy ebook reader) and with Ubuntu installed it is also my primary workstation (for CPU heavy stuff I ssh to a server). But the battery life is 4-5 hours tops. And with the recent ASPM problems in the kernel it got worse. But Phoronix already proposed a solution in the form of a few kernel parameters in a very useful article a few months ago.
Here are the results from the WeTab. It translates to about 20 minutes.