Hey everyone, I have a battery powered heated vest that currently uses a sealed acid 12v/7ah battery that attaches to your belt. As you can imagine, this battery becomes a beast to have to pack around all day. It is basically a motorcycle battery, the same as flyers use in thier field boxes. Being the battery illiterate type, I need help finding out if it will be possible to convert to a lighter lithium type battery with the same voltage/capacity that will save my back! Again, I am clueless to new battery technology, so any suggestions that will give me an equal or better replacement (and charger) will be greatly appreciated. Price is negligible.

Thanks ahead of time!