Some Pure-Fi's has a problem charging 2nd Gen Touch iPod, even when proper supplied adapter is used. You can try pressing the iPod further into the connector and see if it stays charging. If not, you can tilt the Touch slightly forward to make proper charging contact with Pure-Fi's iPod connector.
If you only charge your 2nd Gen Touch in your Pure-Fi, or other devices less thick than the Touch, like iPod Nanos, then you can stick a spacer on the Pure-Fi behind the Touch to always properly tilt it slightly forward. Only space it slightly forward just enough to cause it to charge so as not to stress the connector.
Stick-on chair/furniture protectors work good for this. If they are too thin, stick one on top the other till you get the thickness you need. Do not use any thicker a spacer than needed so as not to stress the connector any more than needed to make charging contact Use thinner stick-ons, like double sided foam tape, to get the final spacing you need.
The added advantage to a proper spacing between an iPod and Pure-Fi, is it relieves connector stress when plugging in and using an iPod while plugged in, since the taller Touch iPod cannot tilt backward. If you place your spacer at the very top of the Pure-if back panel, then iPods thicker, but shorter, than the height of your space can also be used.
Hope this helps everyone with this irritating Pure-Fi design problem.
To view the charging/not charging status on the 2nd Gen's screen, turn off the 2nd Gen and the Charging Icon will show when contact is being made.