Hello there!
I actually posted this on two different forums a few weeks ago, and although it pertains to a mod I made to my bike, this is just as relevant to riding a scoot. Furthermore these have been the most effective method of keeping my hands warm yet, so I thought I'd post it here. Anyway, it's a good value for money option on E-bay £35, and frankly of all the "ideas" so far for warm hands, these rock! With a decent set of winter gloves these keep your hands well toasty, IMHO better than heated handlebar grips, or the battery heated gloves. I've got heated grips on my scoot, which are good, but not as good as these. Plus there is no thermostat to go wrong, or to cut power to the grips when you most need them... Power drainage is supposed to be a maximum of 18 watts, so nothing too heavy... They do make the handlebar grips a little thicker, but if anything this makes it more comfortable. Note, the inside of the grip is rubberized so they don't slip when you twist the throttle.
http://cgi.ebay.co.uk/OXFORD-HOTHANDS-HEATED-MOTORCYCLE-OVER-GRIPS-HOTGRIPS_W0QQitemZ360115626671QQcmdZViewItemQQptZUK_Motorcycle_Parts?hash=item360115626671&_trksid=p3286.c0.m14&_trkparms=72%3A1301|66%3A2|65%3A12|39%3A1|240%3A1318
I treated myself after reading this USA review.. (you can get these in the States too)
http://www.webbikeworld.com/r3/heated-motorcycle-grips/
And the review is quite accurate, they are excellent, and IMHO even better than BMW's own super expensive fitted grips. Alas on mine the little LED doesn't work, but otherwise the switch is fine. I'll get a new one under the 2 year warranty when its warmer weather and I don't need them on the bike...
Ten minutes to fit, and another 30 minutes to find a convenient route for the wiring harness.... However, dependant on which scoot you ride routing the wiring harness from the battery may take a bit longer if you decide to remove bits of tupperware to get to the best "route." On my bike it was easy. From the battery and with judicious use of several cable ties I ran the main wire up under the right hand side of the tank, under the right of the head stock and up to the right hand handlebar, to under the switch cluster. The grips velcro over the handlebars, and have their own little wiring harness that was easy to wrap around the existing wires and cables on the handlebars. I mounted the on off switch on the top right handlebar, on top of a bit of rubber to stop it sliding about.
As to the block connectors joining the main harness to the handlebar grips, I left them loose under the right handlebar switch cluster so it's easy to access. To stop them flapping in the breeze and to keep them safely tucked away and out of sight I wrapped them in a small piece of thick anti slip matting, and stuffed them up underneath the switch cluster. They are well protected there especially with the wind deflectors (Laminar Ears) I fitted to the fairing a few weeks ago.
An added bonus is that the connectors are the same type that my Optimate battery tender uses. So I can also use the connection for connecting the battery to the optimate.
For £35, and 40 minutes of your time, (give or take!) these have got to be one of the most value for money options for keeping your pinkies warm over the winter months.....
If you really want to go for super warm toasted hands, (though this IMHO is overkill, unless you ride in really cold climes) then you can also get some of battery heated gloves on E-bay..... For even as little as £10-£15 you can get them, including those whose heating element runs across the back of the hand. However they are not "bike gloves" so a good overmitt is needed if it rains.....
On a final note, don't forget, that with these grips, it takes minutes to take them off... So in the summer if you don't want your super cool looking handlebar grips to be hidden by a thick layer of ugly heated velcro, well no problem... Just take em off...
Happy Riding!