Having spent the evening searching for a battery that will charge and discharge, or "a pass through power bank" I've drawn a blank.
The limefuel ones are recommend but only in the states.
What are you using with your Dynamo hubs ?
Cheers.

Anker - have a look at amazon

Taylor wrote:http://www.amazon.co.uk/Patriot-2000mAh ... ot+2000mAh

Cheers. Ordered