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1. On December 8, 2023 at 12:08 pm, xtphreak said:

   Different usage, but I’ve been using electrically heated clothing for roughly 20+ years on motorcycles.

   At first a home-made vest using some carbon-fiber pads I bought off eBay sewn into a cheap fleece ski vest (total 24 watts) controlled by an on-off switch, then I bought a gen-u-wine factory-made jacket liner (heated chest, back, sleeves and collar) total 75 watts controlled by a solid-state variable conroller.

   Heated glove liners (thin polypropylene liners with a 26 AWG Teflon wire in the seam following the periphery) each 7.5 watts or 15 watts for the pair controlled by a switch.

   Heated grips 35 watts the pair controlled by Hi-Lo switch.

   Heated sox (forget the brand) I opted for the ones with thin wiring that covers the toe area and foot base because that big toe gets coldest sticking out in the breeze controlled by a switch.

   I had the manufacturer replace the jacket liner controller three times for failure, so I use a modified (home-made) PWM (Pulse Width Modifying) DC motor speed control circuit for a controller for the jacket liner and another for the sox.
   Only has 9 components and for the application is way over-engineered and under-stressed.
   Cost is <$8 plus about 30 minutes of my time to build.

   It uses an LM555 to pulse at about 15 Hz, duty-cycle controlled by a 50K Ohm pot, driving a STP100NF04 MOS-FET transistor (T-220-3 package) rated at 120A continuous drain current with a drain-to-source resistance of 4.6 mOhms (0.0046 Ohms).

   All that means it produces almost no internal heat (< 0.04 watts from the MOS-FET with a 100 watt output load) to cook the components which are encapsulated in potting compound.

   My prototype has been in use every winter since 2006.

   When the lithium-poly batteries came out, I looked into using them since the potential instantaneous short circuit current is absolutely crazy (and using the PWM controller would be perfect), but why carry multiple batteries and recharge them when the 12 VDC battery and alternator on the bike will produce all the power needed as long as it can convert gasoline into electricity?

   Which is when you are riding and the wind chill from 70 mph at 30 deg F works out to about +9 deg F.

   I've used the little chem heat packs when hunting, but this has me thinking I can buy a lithium-ploy battery and try the gear I already have.

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