Not a good idea. There are some customized components in the linpus distro. By using yum upgrade from fedora repos you are essentially trying to upgrade your system to Fedora. Better to install Fedora from scratch or use the linpus live update. Yum is only good for installing additional software, with the small risk of breaking something if the installed software has lots of dependencies.
In 3 days, a completely turned off laptop discharges by 6%