Electrically heated vest

I've found an electrically heated vest (6 AA) on line at a good price.
It uses the carbon fiber heating elements.
Does anybody have any first hand experience with these?

6 AAs can't make much heat for long.

Still, it might be better than nothing.

Can you link the product in question? I've been curious about self-heating clothes for some time.

Fallingwater said:

6 AAs can't make much heat for long.

Still, it might be better than nothing.

Can you link the product in question? I've been curious about self-heating clothes for some time.

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heated vest

I remembered it wrong and it's 8 AA. Nicer as this will allow a 12V source with little problem.

Alkaline batteries are a pretty poor storage medium for energy to be used as heating.

The human body is already a 100W+ heater. It would be more practical to invest the engineering (and money) in a jacket that insulates better.

Thats the first battery powered vest ive seen. There are heated vest/jackets that are used when riding a motorcycle and those plug into the bike

I have a Gerbing heated liner.

http://www.gerbing.com/Products/Liners/heatedJacketLiner.html

It is meant to be worn under a bigger jacket but I wear it in the spring and fall by itself. It runs from 12v, but I have made up an adapter to use 6 AA's in each inside chest pocket balanced for weight) wired in parallel for twice the run time. The jacket normally pulls 6.8 amps at 12v or 80w, but on AA's it is running about 7 volts at 3 amps or 20 watts. It runs for about 90-120 minutes on NiMH's. It is more than warm enough for me in 20F weather. The batteries do warm up a bit adding to the heat

On a side note Gerbing's makes a really neat "thermostat" what it does is switch on and off at different rates to adjust the warmth. From being on 100% to about 1/16 of the time, it pulses in about a second interval. I had to get it because I couldn't wear the jacket plugged in to the car on full for more than 5 minutes.

Having said all that they are pricy, but man at 80 watts on full, they get really really warm.

:twothumbs on Gerbing's.

I bought my vest for motorcycle use and it has been the best product of its type that I have used. I liked the vest well enough that I later got the sleeved model (jacket liner ?).

Mine have been used in unheated trucks and tractors, but I never considered that they could be run on a portable power supply. Nice idea.

asdalton said:

Alkaline batteries are a pretty poor storage medium for energy to be used as heating.

The human body is already a 100W+ heater. It would be more practical to invest the engineering (and money) in a jacket that insulates better.

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Let's borrow some NASA ideas. Put a layer of metalized plastic film, but thicker (and quieter) than a normal reflective blanket in the jacket and you'll have a tremendously light jacket that's also extremely warm. NASA uses 10 layers of metallized foil with dacron between on the space station. That insulation is less than 1/4 inch thick and provides a 250˚F temperature differential, so a single or double layer of metallized foil would be alright for earth.

LukeA said:

Let's borrow some NASA ideas. Put a layer of metalized plastic film, but thicker (and quieter) than a normal reflective blanket in the jacket and you'll have a tremendously light jacket that's also extremely warm. NASA uses 10 layers of metallized foil with dacron between on the space station. That insulation is less than 1/4 inch thick and provides a 250˚F temperature differential, so a single or double layer of metallized foil would be alright for earth.

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In the late 60's 3M did a TV add showing a cup in a beaker of boiling water.
You heard a peep, peep, peep, every once in a while as they discussed the technology. At the end they pulled the cup out, tipped it over and a baby chick walked out.
But where do I buy such a jacket today?

I'd want three layers at least. I have a very expensive and massive down coat that is adequate for me in 40 degree weather...
I've always run on about 40 watts and a number of my friends have commented that "I met Mike in the summer and he was wearing a jacket."

I think that the problem with using a reflective heat barrier with the human body is that it's also impervious to moisture. Condensation is something that you definitely don't want in cold weather.

asdalton said:

I think that the problem with using a reflective heat barrier with the human body is that it's also impervious to moisture. Condensation is something that you definitely don't want in cold weather.

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That depends on the system. The army's "Mickey Mouse" Boots keep your feet warm even when they are wet. (So does wool or a wet suit). The boots are the only thing that have ever kept my feet warm. They were invented during the Korean war and essentially eliminated frostbite.
As long as there is no exchange or evaporation, you stay warm and it has been argued warmer than a system that allows evaporation.

The downside is that for just a jacket it would have to seal at neck and waist and you might have damp cloths on when you took it off.