I happened to find a bag of 50 tea lights for 10 cents each yesterday. I got them and set up two as the heat source for my thermo generator. The tea lights probably only put out around half the heat of the bottle cap filled with ethyl alcohol, but they have the advantage of being safer, easier to use (I don’t need to monitor temperature as closely), and most importantly, they last a lot longer. With two lights, I set up the rig outside in the snow. Filled the cooling tray with snow and water and ran the power leads under the door back into the house. After letting it stabilize, I was pulling 1.6V at around 250mA. By itself, that’s pretty lame, but the temperatures were stable, and I let it run for quite a while spinning a large motor. I expect I *might* be able to pull that 1.6 up to somewhere between 1.7 and 2.0 with better cooling techniques. With that kind of voltage and that kind of current, I *might* be able to boost it to 5V for USB power. I’m in the process of building that booster now. If it doesn’t work, I may need another thermoelectric module. That would put me at a very solid 3V, and probably more. At ~30$ a pop though, they aren’t cheap. So I’d like to see what I can do with one first. The other thing to consider is that the module I have is actually rated to 5W (which I find difficult to believe). The temperatures used to get that much power (and the massive cooling involved to keep the differential high) are more than I can reasonably achieve in the package I’m working with, and they’re more than I’m willing to shoot for. The heat source almost has to be candles. They’re easy, safe, long lasting, and they do burn quite hot, but not 5W hot.