Many years ago, a brainstorming friend of mine was talking about making an electric blanket vest to keep him warm during a particularly cold tramp (there was no way as you would have required a very large battery to keep it going ... let alone charging the battery).
Wonder how long before we start seeing hi-tech clothing with USB ports :-)
The website states up to 8 hours before needing to be re-charged. Bit difficult in the middle of nowhere and no electricity supply. Curious about how much weight the electrics add to the garment? Don't think I would care for the extra weight.