The battery box car based upen an idea from Gambort.
http://www.flickr.com/photos/gambort/2517979228/in/pool-legotrains

I used this 2 pictures to create the box car in some different colors and bought
the Lego bricks direct from http://shop.lego.com/pab/

Cost round about 30eur for the bricks.
8eur for the battery box.
http://shop.lego.com/Product/?p=8881


This is much cheaper than the new lithium power function akku
for 57eur + charger for 25eur
http://shop.lego.com/ByTheme/Product.aspx?p=8878&cn=587


I found out the cable is little bit too short, therefore I used a 'cross
axle extension 2m' to move the machine 2 nobs to back.

Regards
Lars