Author Topic: 12 Volt DC car rear window heaters  (Read 6281 times)

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David HK

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12 Volt DC car rear window heaters
« on: January 13, 2011, 01:34:46 AM »
These days many car rear windows are fitted with 12 Volt DC heaters to "burn off" condensation and if hot enough snow - I think.

They appear as a few dark horizontal lines on the screen which seems to be a plastic sheet base.

Why can't these be peeled off and somehow reused as wraps around underground water supply pipes for hydro turbines etc.

Has anyone ever experimented?

Is it a viable option? What are, or could be, problems?

I am sure comments would be of interest to all the forum viewers .

David in HK


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Re: 12 Volt DC car rear window heaters
« Reply #1 on: January 13, 2011, 06:57:43 AM »
Even if you do get it off its not going to work on a metal pipe.
If you can get it off the glass.


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Re: 12 Volt DC car rear window heaters
« Reply #2 on: January 13, 2011, 08:01:27 AM »
I do not believe it can be removed from the glass.

They are not very Heavy Duty.  Very common to have some of the stripes not making heat after a few years.

25 years ago, they were sold in kit form.  I looked for the kit a couple years ago and nobody ever heard of it.  Almost all cars (here) now come from the factory with it installed.

They make quite a bit of heat.  It does not take very long to melt 1cm of ice, or 6cm of snow.

"Pipe Heat Tape" would be a better solution for pipes.  High voltage AC.  Common (meaning cheap) and easy to get here.
Probably best with a battery system anyway, because the distance from the battery to the pipe is usually quite far?

You can be sure, if I was him, that hydro pipe would have pipe heat tape on it before long. 
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Re: 12 Volt DC car rear window heaters
« Reply #3 on: January 13, 2011, 12:22:00 PM »

Rear screen heaters are printed onto the glass, so peeling it off is a none starter. As already stated you could buy a plastic film with the element printed on to that, but modern cars heated rear screens are standard equipment, in fact some cars have thin wires built into the glass on the front screen as well. Look in auto jumbles for the units from the 60s which were a stand alone element in a frame that stuck to the screen with rubber suckers. (for a while)

Most screen heaters are around 100W, and you can buy on EBay little 12V 100W blower heaters for de icing locks.  100W at 12V is nearly 10 A so you would need a lot of surplus power to make anything usefull.



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Re: 12 Volt DC car rear window heaters
« Reply #4 on: January 13, 2011, 12:54:16 PM »
I remember JC whitney used to sell the kit years ago. Was a peel and stick application.
Might see if they still sell the kits.
I used it on an old 67 VW beetle and it worked great.

Here I found it

Hope it Helps David



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Re: 12 Volt DC car rear window heaters
« Reply #5 on: January 13, 2011, 09:22:35 PM »
Man, wouldn't it be nice eh?

Like the other gentlemen have said, it's a long way from the batteries to where the heat would be needed on most systems. Mine is 450ft from the house, where the batteries live in insulated comfort, so, if anything, an AC heat tape would be the way to go. I'm  sure thinking about it right now, cuz I HAVE dug twice!
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Re: 12 Volt DC car rear window heaters
« Reply #6 on: January 14, 2011, 08:58:32 AM »
Those 120 volt ac heat tapes will work with dc volts. you might try using  a car alt  and a mower engine to power it just bypass the regulator and they will make  plenty volts .I have used them to power 120 volt ac-dc grinders.You will half to use a battery just to run the field. and keep it isolated from the alt output.


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Re: 12 Volt DC car rear window heaters
« Reply #7 on: January 16, 2011, 05:41:04 PM »
If its steal pipe you could connect power directiy to it (low voltage). we have used a welder to thaw pipes. adjust the voltage to get the heat you need.
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