A little information for those who may be questioning whether their phone would benefit from this charging system.
I have a Nokia "Touch & Type" phone, part keypad, part touch screen phone (probably very old technology to some) - it was supplied with a USB to Micro USB converter lead - it was this lead that I had anticipated using with BT's Power Pack to give me a bit of charge flexibility at the Moot.
With this (Nokia supplied) lead connected to the Power Pack, the phone screen reads "Charging device not supported!" so I thought I might have forego my phone as I had in previous years.
However, since I am not so far advanced in technological terms as some (no Ipad, no Iphone, no tablet-doohickeys) I was in a position to have to buy a mains/car type charging unit for BT's Power Pack. I wandered into my local Tesco's (other electrical retailers are available) and bought a "multi-input, multi phone charger" for a little over £10. Within this kit was a Nokia converter which connects to a short USB lead, charging via the normal Nokia charging input.
Using this system of connecting my phone to the Power Pack, the phone charges as normal and gives me the ability to charge the Power Pack from mains, car or USB - also I can very likely offer charging assistance to other people who use a range of phones as I have five other adaptors.
In all, I believe that BareThrill's Power Pack, is a little more versatile than he might have thought!
Thanks BT
Ogri the trog