By now we should be holidaying on the moon, right? That's not going to happen anytime soon when we can't even charge a phone without a connection back to a power station. Surely there should be a way to get enough energy to charge a phone and a light whilst away from the mains? I keep looking into this and it's surprising that there is still no solution. Oh, there's some things... Solar power - Might work with a big panel in full sun in a hot country for a whole day for just enough energy for a half a phone charge. In the UK? Forget it. Stove chargers - Either built-in like Biolite or bolt-on like Powerpot. Either way, you need fuel for a couple of hours to charge a phone, even then you'll be lucky. Fuel-cells - Been a few on the market and they have all failed. They are either stupidly expensive, stupidly heavy or just don't work. Usually the latter. Wind-up - The clue is in the name. You can crank one of these until your arm drops off and you might be able to make a 20 second call. And that's pretty much it. Well, apart from carting along something approximately the size and weight of a brick that has enough power to charge your phone twice. Am I missing anything here? Surely someone sells a UL RTG (https://en.wikipedia.org/wiki/Radioisotope_thermoelectric_generator)?