If you recall, I looked at electric hand warmers for Care Package 3.0 but the ones I saw at the time offered pitiful run times of around two hours. I did a little more digging and discovered the higher end electric hand warmers have a (claimed) run time of as much as six hours.
Now that's more like it. Still only half of the whopping 12 hour run time of a normal Zippo hand warmer that runs on lighter fluid, but it's rechargeable from USB. They can plug it in to charge wherever they charge their phones, for free. Lighter fluid costs money.
The next factor to consider is that this electric hand warmer functions as a power bank. That's both a plus and a minus. On the upside, it means the ability to carry energy with which to recharge a smartphone, in the same unit that also warms your hands. This takes up less space in the care package than separate power banks and hand warmers.
However, it means they'll have to choose between staying warm and recharging their phone. It's 5,200mah which is nothing to sneeze at. They can probably use it for both without much trouble. However putting lithium batteries into something that heats up seems unwise, as at the very least, the heat will diminish the longevity of the batteries.
Is it worth a 50% reduction in runtime to combine the power bank and hand warmer into a single unit, eliminating the need to buy lighter fluid? That's going to depend on two factors: Whether it heats as effectively, and whether it really runs for 6 hours.
So I bought one for testing. At $21 it's a couple bucks cheaper than the combined price of the $13.47 regular hand warmer and the $13 or so it costs per single 18650 power bank. It doesn't heat as long as the regular, fuel burning hand warmer but it does store nearly twice as much energy as the power bank I included before.
It just got here today, so I have to charge it up first. But then I'll test out how long it actually heats for, on the highest setting. If It lives up to what the Amazon page promised, and you guys think it's a good idea, I may substitute this for the fuel burning hand warmer and single 18650 in Care Package 4.0.
Stay Cozy!