My Biolite Mk1 and Cookstove have proved their worth as practical stoves, wood-fired grill (with the attachment) and, as I found at our CCS gathering at Newark chatting round one of them into the night and inside our ‘Fettler’s Arms’ event shelter, as a controllable camp fire providing warmth and somewhere to gather round and stoke with fuel. Inevitably, I felt compelled to save my pennies to buy the Campstove 2 to try out, which I’ve soon concluded incorporates the strengths of those other two versions - an abilty to charge a phone (like the Mk1 but much better) and a larger-capacity battery than the Mk1’s (which the Cookstove benefits from). Progress in product development, certainly. Comparison, the power units side-by-side, Campstove 2 on the left. Campstove 2 has a bulkier thermo-electric generator probe, made out of cast aluminium and not copper this time. The TEG is apparently inherently more powerful, with a greater output than that of the Mk1’s. Coupled with the larger capacity battery, the Campstove 2 can charge a phone very effectively and even when there’s no fire burning - provided there’s sufficient charge in it’s battery to power an external device. The Mk1 was very hit-and-miss as a charging device, though burning for several hours contiuously at Newark (as a camp fire) I charged a nearly discharged phone to full capacity. The stove body has a variation on the hexagonal-hole pierced heatshield (tilted hexagons now). Gone are the ladder-section feet ... ... and the ability to remove the inner firebox liner once the central screw’s undone has gone. No need to remove it in actual fact. Pre-charge of battery on the turquoise-coloured cable (here just to illustrate where it goes) output from the USB port on the front of the unit. Charging of the phone in progress. Couldn’t do that with the Mk1 unless the stove was fired up and hot enough after the fire had been burning for a couple of minutes. Mk1 battery pre-charging done on the yellow cable, USB at either end of the cable. Same port for the output, once attached to the stove and TEG output and battery charge sufficient to power the fan plus an external device. Relative air gap of fan unit to stove casing on Campstove 2 (left) and the Mk1 A gap I reduced on my Mk1 by crafting a silicone spacer, giving better performance The instructions, English and Spanish (plus other languages on the reverse) Irrespective of its improved charging ability, the performance of the stove as a stove is very good. Four fan speeds as on the Cookstove (handy to have), a state of battery charge array and a column of LED’s on the left of the facia to indicate the intensity of the fire at any given moment. It adds to its ‘watchability’ as a camp stove I suppose, but even with a pot on board it’s obvious anyway when the fire’s dying down and needs topping up with fuel. I’d got a hot fire there, looks like this ‘in the hole’ Brew time! John
Great review there as always John. Must look at TEGs for the ND wood burners. Something for the future development project. What would be the feed in tariff do you reckon as an earner for the micro nation?
Lower threshold for FIT than in the world at large for sure! We’re talking 3 watts of power here and not megawatts, but small beginnings ... Build a (large) TEG into that wood gas stove that Terry entrusted us with at Newark and you’re getting a viable resource to qualify for a FIT.
no pennies - he's got zillions of pounds though! good to see the mkII really is an improvement on the mkI and not just a 'facelift model' anyone tempted to buy a discounted mkI would clearly benefit by spending more and getting the improved version
@Rickybob I think as John as mentioned previously, the USB power charging was a little over sold. The fact it will drive the fan in use is good on it's own, which is the limiting feature on the cookstove without the ability to recharge. Just picked up a small solar charger/powerbank for £12.99 to see how that performs, look for BSAMZ. It arrived yesterday and charged overnight, Now need to cycle it to see how the panel performs recharging itself. 10000 mAh. @presscall A very quick look for TEG's last night would suggest they are not cheap. Need to look at ratings and mounting arrangements.
Thank you John. The negatives of the MK I are mostly taken care of in the MK II. I will wait to find a used one. I do think that is less likely now that a MK II will show up used, as they seem to be a much better stove, and those that buy it will more likely be happy. That surprises me. I had trouble keeping the charge light lit. (Is this MK I the one that you modified?) But, I did not imagine sitting around a BioLite as a campfire. Very 'outside the box'.
@snwcmpr It was the one I’d modified, Ken, yes. That helped I suppose but primarily it was down to the fuel - a large stock of pre-prepared kiln-dried hardwood offcuts for fuel of the right length and finger-thick - and the fact that we were sat around the stove and methodically feeding it with fuel on the ‘low’ setting (mostly), so the fire didn’t have a chance to die down momentarily and the stove stop charging. I’ve taken some photos of the internal components of the Mk1 (on the left) and Mk2. The upgrading of the battery on the Mk2 and the larger heat pickup spike are obvious in this shot. So, more heat gets to the ‘hot’ side of the TEG, while the bigger cooling fin array (more fins and more surface area) ensures the cooling of the ‘cool’ side of the TEG is maximised. There’s no obvious phyisical difference between the two TEG’s themselves, so if the TEG in the Mk2 has been upgraded it’s not on size but internal specification. Maybe with the more efficient transmission of heat to the TEG and the corresponding increased efficiency of the cooling on the opposing plate, that was sufficient to up the power output by 50% as claimed? Aluminised foil heat insulation on the Mk1, stainless steel pressing to do the job on the Mk2. John
interesting to see the edge of the teg cell is visible - the individual elements appear to be exposed - I will take a look at my mkII but I would prefer to see some sort of insulating goo applied around the edge that might be a worthwhile mod - the teg on the tegger stove is insulated with goo
it is as I suspected - not even a coat of lacquer bio wotsit to the left tegger to the right I think that is downright shocking for an item intended for use outside I will use a heatsink compound on the 'cold' side of the cell but first I need to get some goo around the edge of that teg cell is maplins still open? - i'm off to the bus stop
saved myself a bus ride - maplins has closed for good so I will order some dielectric compound online because I am not using it like that they could argue that leaving the edge unsealed helps to cool the cell but that is bs if water gets in at the very least it will play up I could run a bit of epoxy round there but I will wait till I have the right goo
@Rickybob, you have buses running round your way on a Sunday. Could I ask a favour while you have yours in bits, do the TEGs have any reference info printed on them? Eg part numbers. In have a few weeks work ahead to understand what might be achievable (affordable) to construct something for natural draught/TLUD purposes. Simon (in public transport isolation)
Sunday buses subsidised by local council - use 'em or lose 'em! teg stove on the left bio wotsit on the right which seems to be bonded to the hotplate - I am reluctant to prise it off for fear of breaking the ceramic backplate which is segmented so may be fragile - so no id visible on that one I have seen similar looking cells ( to the left one ) on ebay for about $5 each including p+p from china thinking of getting some just to tinker with - they got different output voltages available
West or North Wilts? Looks like the useful info is glued on the other side. Output will be approx 5.2V and if earlier info is correct in optimal situation they are rated at 3W. A bit will be going to the fan, and they appear to have improved the temperature gradient. My previous quick reading suggests 150deg c on the hot side, the Mk I may not have been achieving that under normal user situations. Hence the better heat probe on the Mk II.
@Rickybob and @Simes. Thanks for this additional information fellas. Most interesting. Incidentally, I’ve noticed that on my Campstove 2 there’s no slot in the heat probe as I’ve seen on some examples, such as yours RB. I’ve emailed Biolite support to ask why. Theoretically doing away with the slot reduces the surface area to absorb heat from the flame. Maybe not by sufficient margin to warrant the machining/forming expense?
How much larger around is the Mk2 heat probe? The increase in diameter could have easily made up the lost surface area, some measurements and calculations would tell the tale. I bought a couple of those Chinese TEGs to play with, had plans for a kerosene powered cellphone charger. One of those "round-tuit" projects that's been sitting for two years and will likely continue to sit for a goodly while longer. Also had an idea for making the pellet stove in my shop self sustaining, vs. requiring grid power.
I found a Biolite Campstove 2 on a discount for the scratches and dents it has. In original package (damaged also). Only 90.xx USD. And returnable if not satisfied. I like the words John has said about them. The improvements over the MK I. I still refuse to pay full price for one. Stubborn that way I guess. I have no need to use it as a source of power unless the SHTF, and I suppose then I will have more problems than just that.
The comparison I’m drawing is between the two types of probe (one with a slot in it, the other without) on the same Campstove 2 model. Looks like they have a probe of the same length and diameter, but differentiated by the slot in the (earlier?) production examples.
I’ve used it a lot this week Ken and it’s done consistently well. I cooked rump steak yesterday on the grill attachment and stove and grill ensured it was beautifully cooked - seared at the outset on both sides on a grill got really hot on the highest fan speed and a good stock of oak sticks in the firebox to maintain the heat. ... then cut back a bit to the 3rd speed and a slight reduction in fire output (one less LED illuminated on the heat output indicator) and finally down to the lowest speed and a charcoal glow of embers for a ‘resting’ period while basting the steak with a teaspoon of honey and what was left of a soy sauce, ginger and garlic marinade. Pre-sliced to serve with salad. As that was going on I had my phone linked up and it had gone from 68% charge to 84% and the charge indicator on the stove was still showing full charge (I’d pre-charged to full). So it had more than maintained its output to the fan at full speed for a good part of the time as well as to the device plugged in to it.
Well, nevermind then. I could see problems transmitting heat from the tip of the probe through the narrower edges of the slot to reach the the main body of the probe and the TEG. Increased surface area sure, but I can see how it may not add as much as it seems. I imagine they have some pretty serious testing jigs, finely controlled flames or possibly electrically heated hot air blower, to find the right mix of probe shape, TEG output, manufacturing cost, etc. Guess the slot wasn't worth it. THAT is a very serious improvement. That's the difference between "self powered forced air stove w/ toy-like possible charging ability" to "all the previous, plus the charging is now a real world useful tool." Well done Biolite!
