Reusable hand Warmers??

Santos · **on:** January 22, 2022, 02:33:05 PM

For the record, I always thought the chemical hand warmers were only available in a single-use disposal variety.
So naturally, I hated them with a passion.

Moments ago I came across a reusable one and it blew my mind. Suddenly the applications seemed appealing.
Who here uses one? How many reuses do you ridiculous get out of a 'quality' unit. I see it as a great thing to add to my canyon first aid kit or take travelling. (I generally layer properly this is not meant as a substitute!)

This leads me to the second thought, what would be more reliable and last long term. a RECHARGEABLE USB heater element off a small power bank or a chemical hand warmer?
The USB one would certainly be easier to reset in urban environments whilst the chemical one has simplicity in just boiling it.

I have been musing a small solar power bank with built in led light for travelling, but part of me is really concerned about the reality of leaving a lithium battery heating up in the sun from a safety and batterylife standpoint

Tasky · **Reply #1 on:** January 22, 2022, 11:19:16 PM

Well....

There may be other kinds, but the only reusable chemical one I know of is the one where you bend a metal plate to make the crystals heat up and go solid, and then you boil it to reset it.
I have had some of these before and they're OK. Not especially hot and don't last that long.
I've not had any 'wear out' as such and in theory your reuses are infinite. Most manufacturers suggest 2-300 uses, as you're more likely to tear, split, puncture or just wear through the casing. This is the biggest issue if you're an active outdoorsy kind of user, as you need to keep it well protected when it's stowed in your kit - Sharp stuff can pierce it, crushing movement can burst it and even a hard impact can trigger the 'snap' reaction that heats it up, meaning it's useless when you come to actually need it.

Over the years I stuck with ye olde charcoal stick warmers for many of the above reasons.

USB hand-warmers have the advantages you mentioned, plus the ability to just turn it off and save some battery for later... and most have different heat settings/levels too, which the chemical ones do not.
Not sure about number of recharges and I think it would depend on the batteries they use - For example, the 18650 cells I use in various bits of other kit are rated for at least 500 complete recharges.
I got a Zippo one for Dad-in-law, who has Reynauds, and that came with a 2-year warranty so presumably it'd have to do for up to 700-odd uses...

No idea about solar charging, but if the powerbank is designed for it, I don't imagine much of a problem.

Vidar · **Reply #2 on:** January 23, 2022, 02:37:38 AM

Various tool manufacturers make heated jackets and what not which are compatible with the batteries for their tools. The 12v variants shouldn't be too chunky I imagine.

I've tried various warmers over the years. So far nothing beats bringing an extra layer of clothes and or suitable hand/ feet/ head add-ons as needed. No charging necessary, always works, and just keeps working. That is when you can roughly predict the need in advance. Then there are situations like emergencies or task which prevents you from using the (potentially bulky) warm enough clothes. And for those I think a setup driven by a battery back should be better than a chemical reaction - it can certainly be better controlled.

Santos · **Reply #3 on:** January 23, 2022, 10:23:25 AM

Tasky, You have more faith in the product development team and I do!

One issue for equatorial and southern hemisphere region is the sun is stronger than european/ North American and a black battery bank is going to soak up all that heat. My mobile phone when charging in direct sunlight often give me a warning that its stopped charging due to excessive heat and i am not confident even brand names have

I also have seen so many solar things that just don't have the ooomph to charge a battery. If the battery is full it will trickle charge but when battery is empty it is not going to anything even if left for days. The feedback on the chemical ones help. I like the charcoal warmer idea too, may look into that for wilderness trips or when air travel isn't part of the overall trip.
world
Currently looking at a compact HRD900 hand crank radio to use as a powerbank which has a easily removable 18650 battery.

a tad bulkier than say Uniden UPP80S Solar Powerbank

but i can swap the mystery BS '2000mha'battery for a quality Panasonic 3500mha one (and keep the other as a charged hot swappable spare) and not worry about the solar aspect.

Vidar, agree with you completely on packing the right layers and not relying on a power source. Almost everything I wear is merino from summer through to deep winter weights. Recently i have started embracing alpaca, still not sure about the claims its warmer for less weight over merino but it works at least as well as the same thickness in wool.

Someone I subcontract for bought one of those AEG heated Jacket and i thought they were the smurfiest thing ever. A cheap synthetic windbreaker with a battery pack lots of wires and heating pads? So many failure points that a Thinsulate or Wool layer would eliminate. The one he got was AEG brand and as i predicted it he only used it a few times before replacing it under warranty and I'm confident he willkeep having problems. For one just the range of movement is going to create breaks in the wires and the battery just doesn't last full day and will deteriorate under the current draw. Small batteries+ large current load = short lifespan.

Vidar · **Reply #4 on:** January 24, 2022, 03:26:11 AM

Quote from: Santos on January 23, 2022, 10:23:25 AM

Vidar, agree with you completely on packing the right layers and not relying on a power source. Almost everything I wear is merino from summer through to deep winter weights. Recently i have started embracing alpaca, still not sure about the claims its warmer for less weight over merino but it works at least as well as the same thickness in wool.

Not sure about alpaca, but on the exotic side here mosk ox wool has a good reputation. As the animals have the unfortunate combination of aggressive behaviour, not being afraid of humans, and simply being huge, the wool can be hard to come by. Keeping an eye out for the nearest tree and bringing food and drinks to potentially stay up there for a long while is supposedly part of the charm.

It is typically merino wool for me all through winter. Sometimes in combination with a more moisture transporting inner layer if the activity level is high.

Santos · **Reply #5 on:** January 24, 2022, 06:37:30 PM

Quote from: Vidar on January 24, 2022, 03:26:11 AM

Not sure about alpaca, but on the exotic side here mosk ox wool has a good reputation. As the animals have the unfortunate combination of aggressive behaviour, not being afraid of humans, and simply being huge, the wool can be hard to come by. Keeping an eye out for the nearest tree and bringing food and drinks to potentially stay up there for a long while is supposedly part of the charm.

It is typically merino wool for me all through winter. Sometimes in combination with a more moisture transporting inner layer if the activity level is high.

Something better moisture wicking than wool? Sounds synthetic!

Would love to try the Brinje Woolnet or Aclima Merino mesh 'fishnet' underlayers but it is so expensive full price with shipping to Austalia. I imagine they would breathe amazing as the underlayer.

Vidar · **Reply #6 on:** January 24, 2022, 07:38:23 PM

Brynje is very nice but also expensive - even in Norway. More on the work side wool fleece tends to work well and is far less expensive. (And will from experience surround weld droplets that goes through your outer layers in melted wool balls. Much preferable to them being stuck in melted skin instead).

Personally I raided New Zealand for lots Icebreaker stuff some 15 years ago or so. Back then they were half price to the Norwegian ones, and I liked them better than the alternatives back home at that time. So I filled my luggage with those and some Australian wool socks. I still consider that a most successful shopping spree. The tops are still in regular use, while the long johns got replaced by some Swedish and Norwegian stuff some years ago.

Anyway, how hard can it be to make a heating element that can plug into any common power bank or USB plug? (Or cell phone for that matter). It wont keep you alive in cold as such, but it might provide a bit of comfort to hands or feet for a while.

Tasky · **Reply #7 on:** January 24, 2022, 07:50:48 PM

Quote from: Santos on January 23, 2022, 10:23:25 AM

One issue for equatorial and southern hemisphere region is the sun is stronger than european/ North American

Sun? What's that?
I'm from the UK... where The Sun is nothing more than a tabloid newspaper!

Can you not get a separate solar charger that just has the solar panel, and thus charge the hand-warmer/battery bank somewhere out of any direct sunlight... maybe inside a backpack, with just the lead going out to the solar panel?

Vidar · **Reply #8 on:** January 25, 2022, 02:05:50 AM

The solar panel concept wouldn't do much good around here. Winter season here is cold because of little to no sun for months. Which would leave the solar panel heater nice for the summer season when you don't need it.

Santos · **Reply #9 on:** January 25, 2022, 02:50:54 AM

Feel like i may have fallen into the gadget trap. You know the one, where you keep deviating further and bulkier from the compact starting poitn.

Two small power banks that use 18650 a single battery each probably are lighter and easier to carry. Keep them both charged and swap them out. there is a kit on ebay with led flaashlight for AU$7.50. I can get genuine Panasonic or Sanyo 18650 super cheap through a friend who works in a battery shop.