I agree with TT. Been running Oxford HotHands for a couple of years or more now to make the winters easier, and at 12v it's do-able. I reduced the headlight to 35/35 halogen. Those particular grips need about 35W, so that's 70W gone. The dynamo is good for about 80W continuous at 12v using a DVR2 in my case, so it's a near thing with tail/speedo as well. Not a lot left for battery charging. The ammeter shows we're breaking even or a bit better on the open road, but in town it's not so good. However, without all lights blazing, no problem at all - and she runs all day like that when it's cold. My fingers think they're great, I haven't fried the dynamo so far, and the battery I'm on at the moment seems to be holding up OK too.