TankMaster writes -

Today I was finished with a little project I have been working on. It took about two days of internet searching and ideas The result is a modified USB cable with a SE Fastport connector, I have tested it with my SE phone C510i and it works great with Mintyboost !! With one set of batteries I got approximately a 12 % increase of the battery life, it took about an half an hour to get that.