The bike I chose was the Kudos Tourer with Nexus 8-speed Hub. It's quite an interesting setup, and not very well documented, so I thought it was worth a few notes.
The battery pack slides on to a shelf on the rear pannier. It is a 36V nominal 10Ah pack, which charges up to 42 V open circuit. It has a key switch and the battery management and balancing must be internal. There is a four pin socket on the back, of which two pins are connected, and an RCA phono jack under the handle for charging. The charger is from Sans and its rated output is 42V 2A. My first battery wouldn't charge and my second had an intermittent cutout. Hopefully my third will be reliable!
The battery power comes into a hollow plastic box stuffed with wiring. Tidy it isn't!