I had seen some favorable reviews of the S Boston, but it did not fit into our criteria of 'affordable'. But what caught my attention was the claim it can reach 167F. As I'm overjoyed to get a Chinese model with rebuilt head past 140F, I thought I'd give them a try. (Remember that higher heat is not just about keeping your pocket cavity warmer. More importantly, the extra latent heat means that your handwarmer does not go out as easily because your reservoir body does not get cold shocked below the boiling point of the Naphtha as easily). The engineering on these certainly seems to be much better at least.
Update: In Nov of 2017 I finally did a review that was a little more comprehensive in scope then those existent on Youtube to date. In that review I also determined it is possible to replace the catalyst head on the S-Boston. The review can be seen below.
Of course I have no interest in anything that is so perfect, that I can't hack it and make it better. After all, She Who Must be Obeyed has applied that strategy to me, and look at me now - the unsung and undisputed Handwarmer King in a town of 6,500 residents.
So here's me looking at the S Boston videos on Youtube. And I have the following thoughts:
- AAA batteries? The problem with this rather dated form factor of battery depends on which chemistry you select. A 'AAA' alkaline cell does not perform very well in cold weather at all - the very place and time you really need it to work at the top of its game, so forget about using them in a handwarmer. AAA 'primary' lithium cells such as the energizers work well in the cold, but are very expensive, not rechargeable, and when placed in series, their high voltage can damage some circuits. NiMh LSD rechargeables (such as Eneloops) kind of work, but because they have a very high self discharge rate, and low capacity, as well as low voltage, they are not the optimal choice for this sort of application (one reviewer noted he had trouble starting his S Boston handwarmer with low voltage batteries). So, we could do much better with a rechargeable LiFePO4, 10440 cell (same size as AA but chemistry is Lithium Iron Phosphate, same as Tesla uses). Alternatively, perhaps 10440 Li-Co's (same chemistry as what's in your phone, laptop and camera). The plan is to test all of these rechargeable alternatives to see which one works best. (At this point I don't even know what sort of method exactly that the 'electronic ignition' uses and what its voltage threshold is, but that will be an important factor in determining the very best battery chemistry to use. )
- Cotton in the reservoir? I think it could benefit from at least a carbon felt strip under the catalyst head, so the plan is to add that to this value-added offering.
- Speaking of catalyst. The deal breaker on these for many is inability to replace the platinum catalyst. In the video below, we see that it is possible, and easy, to replace the catalyst.
Our S-Boston Review: