Is there any difference in terms of distinct advantages/disadvantages having 2 batteries or just one battery double the capacity?
Trivial question I know. I've been using dynamo lighting for road riding and audaxing for a long while but want to be able to change bikes a lot easier and have an off-road option for night riding. A couple of guys I've ridden (audaxes) with swore by their vision 2's (they had endurance option with a spare battery) as you can just use them on low for most road riding, boosting them up for fast descents and with the two batteries you can get several days night riding out of them. Also the beam pattern struck me as pretty road friendly.