Lithium battery replacement for automobiles and motorcycles
Lithium starting batteries, about 1/5 or less than the weight of lead acid.
When I buy an ATV I would like to try one of these. If I ever get real crazy about weight reduction in my car I might install one.
Edit: started looking around on there web site and found this:
http://www.lithiummotorcyclebattery.com/gallery.html
Note the picture with the caption "29 lbs 250cca vs 2.5 lbs, 300cca"