The electronics module also houses a lithium-ion battery, a fan, and a microcontroller circuit board. In the cutaway drawing, you can see the copper probe jutting into the fire chamber attached to one side of the TEG. The other side of the TEG is attached to a large finned heat sink. The fan draws in relatively cooler air across the heat sink, keeping that side at a much cooler temperature than the side attached to the copper probe. The greater the temperature differential between the two sides of the TEG, the greater the electric current that will be produced.

The primary purpose of generating electricity through heat is not charging your smart phone, it is to run the fan.

The steel combustion chamber consists of three layers. The outermost is a honeycomb perforated heat shield. The middle layer is a solid piece of stainless steel sheet, but with a port to allow in fan air. The innermost layer has a series of strategically placed air jets at the bottom, middle, and the top sides of the fire chamber that circulate fan air to promote very efficient combustion of the wood.

This type of a stove is known as a wood-gas stove. I guess that I never understood how inefficient an open wood fire is. When wood burns it emits a flammable gas. When a fire smokes, that is basically unburned wood-gas plus flammable particulates that are not being burned, but just escaping into the atmosphere. Besides oxygenating the fire, the fan of the BioLite stove recirculates the wood gas and fine flammable particulates back into the combustion chamber where they ignite and burn. As a result, this little marvel burns wood practically smoke-free.

Once the fire gets hot enough for the TEG to produce enough electricity to fully charge the fan battery, the excess electricity is made available to the USB port so that you can charge your smart phone. This is signaled by a LED on the front panel turning from orange to green. The fan has two speed settings, controlled by a single pushbutton switch located above the USB port.

To start the stove, you loosely pile a fistful of twigs into the fire chamber. You can use scrap wood from your household woodworking projects just as well. Fuel sticks of about 3” to 4” long, up to about ½ inch in diameter seem to be optimum. Hardwoods are best, but softwoods work fine. Softwoods just burn a little dirtier and need replenishment more often. The drier the wood, the better. It helps to have a pile of prepared fuel prior to starting the burn.

For starting, BioLite includes some fire starter sticks with the stove. But here I have to reverse myself from something I said in last month’s story. I mentioned Vaseline-soaked cotton balls as a fire starter, but then I said that I prefer solid fuel tablets as tinder. Those fuel tabs work great for starting a camp fire, but I can heartily recommend Vaseline-soaked cotton balls for starting the BioLite.

After rubbing in a generous amount of Vaseline into a cotton ball, I pulled it open to expose the maximum amount of surface area. I then skewered the cotton onto the end of a 4” long wood sliver. With one spark-showering-scrape of a ferro rod onto the cotton it immediately ignited! I then grabbed the other end of the wood sliver and placed the flame among the awaiting twigs in the BioLite’s fire hole. We have fire!

At first, you let the fire get going with no fan-assist. If the flame is still weak, you risk blowing it out if you turn on the fan too soon. You may get a little smoke at startup. When enough wood catches, you can press the fan button once to start the fan on low. This will begin circulating air around the fire chamber and you will see the fire turn into a mini fire-tornado. Any smoke will now clear up as the fire starts to burn cleanly.

To really get the fire roaring, keep feeding the fire, and push the fan button once more to high speed. But here’s the thing: At high speed, the rather small pieces of wood are quickly consumed and you basically have to continually feed fuel into the voracious maw of the beast. Plus at high speed, the fan noise becomes a small irritation factor, and the fan consumes more electricity. The higher temperature compensates for that by creating more electricity, but I prefer to keep the fan at a soft whir on low speed. You still have to keep feeding the fire every 5 minutes or so. You cannot just walk away to attend to other camp chores.

And that explains how to turn off the stove. Basically, you just let it run out of fuel. It doesn’t take long. The fan will turn itself off when the stove cools down enough that the microprocessor decides that it is no longer needed to protect the TEG. When all done, you will be amazed at the tiny amount of ash that remains at the bottom of the fire chamber. The BioLite burns wood very completely and efficiently.

The literature says that the stove can boil a liter of water in 4½ minutes. I have not timed it myself, but I have no reason not to believe that. So far I have cooked up some Ramen noodles, roasted marshmallows, and warmed up some hot chocolate with it, all in my back yard.

So really, why did I want this thing? That’s a little hard to answer. First of all, the fuel for it is free, everywhere, and unlimited. No buying propane canisters or liquid fuel – ever.

Then I have to admit that I am fascinated by the marriage of modern electronics with one of man’s oldest survival technologies. It is very fascinating to see the flame jets of wood gas that come out of the holes at the top of the combustion chamber. The fan pulls the wood gas into the air space between the walls of the stove and re-injects it into the top of the fire chamber where it ignites and burns, looking a lot like a propane flame.

The ability to charge a smart phone is cool, but it certainly was not the big draw for me. I guess the biggest draw for me was looking forward to firing it up in the pre-dawn or during a snowstorm while sitting in a hunting blind freezing my ass off. I’ve been there too many times. It is a perfect little portable campfire. And to be able to warm up some hot chocolate at the same time? Sublime!

For storage and transport, the electronics module unhooks from the side of the combustion chamber and can be placed inside once everything cools off. With the legs folded up and the power module stored inside, the whole unit is about the size of a 32 oz. Nalgene bottle.

It is not a light backpacking stove however. It weighs just over 2 pounds. Backpackers may shun it for that reason, but that’s not too heavy for me to consider packing it along in my ATV, or throwing it in my pack when planning to sit in a hunting blind all day. If I was planning a day of just hiking the hills, I would probably leave it behind. But on second thought, a warm lunch might be nice.

I also received the BioLite KettlePot with the stove. The KettlePot has a 1½ liter (6 cup) liquid capacity and also doubles as a kind of hard case for the stove, as the stove will nest inside. This makes for a rather bulky and even heavier assemblage, probably too much for your daypack, but fine for basecamp. Both the stove and the kettle come with nylon drawstring storage sacks.