The only heated earmuffs I could find were ugly traditional ones with a long cable that goes down to a battery pack you carry in your pocket. What the hell is that shit? I knew I could do better, integrating a single cell 18650 based power bank on the earmuffs unit itself.
The single NCR18650B keeps it running a surprisingly long time. I started it running an hour ago and it’s still going strong as I write this. I don’t imagine a more substantial battery than this is needed unless one plans to be out in the woods in the dead of winter for multiple hours.
Here’s where the wire goes to the heating element. You can see where I cut an opening with scissors to stuff it in the space between the two layers of fabric. There’s also some stiff wire in there to clamp it securely to your head and some sort of dense circular pad.
Here’s the heating element. Each one is actually two wired in parallel so I’ve just folded them over on themselves. Unfortunately this means it’s sucking down twice as much power as it actually needs to, and it currently gets uncomfortably warm.
I’ve ordered a replacement set of heating elements that aren’t parallelized in this way which will still get plenty warm but cut the power consumption by 50%. I also need to figure out how to shorten the wire, I don’t want all the extra bulk. On something that hangs onto your head by gentle compressive force, every gram of weight matters.
Bonus pic of the unit warming my cat:
As you can see, I zip tied the cable bundle to the battery compartment. It works, but it’s ugly and needlessly bulky. To do: Shorten cable, replace heating elements with single lower wattage ones. Stay tuned for more!
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