A portable stove that burns wood that can charge your phone sounds an interesting idea. And with Biolite stoves very, very really coming up for sale here I turned elsewhere. I went searching on AliExpress. And found a Flamecube. A TEG and fan equipped wood stove with a 2500mah battery. I haven’t had the chance to test it yet as I want to wait for daylight light it for the first time and daylight is currently in short supply here. I’ve also got to hunt out some dry wood. the box the contents of the box. The stove, nylon storage bag, “multiplier”, USB cord for charging the battery, and the instructions. The stove in cubed storage mode and opened up for use. USB output port the TEG unit and battery are removable to make it easier to empty the ashes or use it as a unpowered wood stove. the base of the TEG unit has the port for the charging cable the “multiplier” plugged in. A bag you fill with water and connect to the fire with silicone hoses. I expect it works as a thermosyphon radiator to cool one side of the TEG.
I wonder if the battery in it is more user replaceable than on the BioLites. The design seems to pack a bit more compactly.
The instructions say not to use pellets. I guess because of the open grate. I'm looking forward to it stopping raining so I can give the stove a test.
I brought some dry wood and it stopped raining so I had a chance to test the Flamecube. The wood I got was sold as kindling at the supermarket and so is likely to be pine (pinus radiata) since it was machine sawn. I chopped it down further so it would fit into the stove. I'd partially charged the battery and it had two of the five bars when I started the stove. Once the stove was lit and established I turned the fans on. There is two speeds to the fan. The high setting only stays on for a short time. It is obviously intended to keep the fire burning cleanly when restoking. The lower setting goes all the time so as not to damage the TEG. Once the charging lights started flashing I plugged my phone in to see how quickly it charges. Not quickly is the answer. With only 3.7 - 4.5W of output from the TEG it is going to take some time. A better use is to use the stove to slowly charge the battery and then use the battery as a powerbank when the stove is out. I put the kettle on and it brought it to the boil fairly quickly. It is not a gassifier stove so there was a reasonable amount of soot deposited on the kettle with the wood I was using. The fans mean that it does burn cleaner than just a folding woodstove and there wasn't much ash left when it had burned down. After making my cup of Rooibos I decided to see how long it took to charge the battery up using the water cooling multiplier. The multiplier is claimed to increase the TEG output to 5.5 - 6 W. Without my phone plugged it it still took quite some time to get the battery charging. I put my bigger 2L kettle on and it brought that to the boil. I burned a bit more wood but was getting hungry and cold so stopped before the battery was fully charged. It took about a total of over an hour to get the battery from the 2 bars i started with to just into the 4 bars, including some time charging my phone. I'm not sure the multiplier is worth faffing with unless you are desperate to charge something. It's an open topped water container that has no taps on so you have to either tip the whole stove and multiplier to empty or quickly unplug it and move the stove away from the outlet.
A good idea to not put a phone, or device, directly connected to a fluctuating charging system. It can result in damage.
Further testing of my Flamecube today. I plugged the water booster in, filled with cold water and lit the stove. After making the obligatory cup of Rooibos I kept feeding the stove more wood. I also cooked dinner on the stove later on. It took about 2 hours of continuous burning to get the battery from flat to 3 bars. So that's the battery just over half charged. I'm sure it would be quicker plugging the stove into the power socket to charge. During that time the water in the heat exchanger booster has gotten hot so I'm not sure how much the booster is now working. If you had to, and had enough wood, it would eventually charge the battery enough to recharge your phone. I think it is slightly more of an interesting idea than a practical one.
