The dynamo sends power to the front and rear LED lights and also a Tout Terrain Plug II USB charging device. I’m going to review the USB device separately, as it would be unfair to judge them both together. And that’s because the dynamo hub does an excellent job of providing power to the lights, when turned on via the rotating switch which circles the oversize hub.
One small gripe here though, you can turn off the front light independently, but not so with the rear as it has no separate switch – so if used with a working USB charger, would remain permanently on. Good bit of kit.
By the time I had arrived in Dieppe, my mobile phone was on just 11% battery. On starting the ride, I plugged it into the Supernova charger and began cycling. A green LED comes on to confirm when it is charging and blinks when it is not. Within a couple of hours the phone was fully charged, despite running my GPS constantly on it. I was pretty impressed!
Their is only a small difference in the resistance felt from the dynamo hub and it can be turned on and off by means of a large circular switch on the side of the hub, a really nice feature. Over this first week I found myself fully charging the phone and then turning off the hub, although as I said the resistance feels quite minimal.
I knew that the lowest speed the hub worked at was around the 5 mph mark, anything slower and not enough current is being produced. What surprised me was that their also seems to be a top speed it will not work above, about 40-45 mph. This was not really a problem until my final 20 km’s on Sundays stage, where I was climbing and descending constantly through a forest. The phone was not being charged on the uphills or the downhills and it actually ran out of juice, not good when you are relying on it’s GPS! As it happens I had my backup laptop battery to charge from, so was only inconvenienced for one of the long climbs.
I intend contacting Supernova to discuss this with them and I’ll report back their comments. It does concern me when you look at some of the mountain routes I will be taking.