Harbor Freight sells a small plugin electric heater that is designed to set on your dash - 156 Watt. http://www.harborfreight.com/12-volt-auto-heater-defroster-with-light-61598.htmlPerhaps this would suffice.
-- David On Tue, Jan 21, 2014 at 8:28 PM, Ron Frazier (TECHC) < [email protected]> wrote: > On 1/17/2014 8:20 AM, Jim Lynch wrote: > > On 01/16/2014 10:49 AM, Allen Beddingfield wrote: > > This is my Facebook status this morning, but I thought I would throw it > out here for people to discuss :) > > With all of our technology, why do we not yet have an instant-on source of > heat for defrosters in cars? Sure, the manual in the car says that modern > engines don't have to be warmed up, etc... what good is that if I still > have to let the car sit for ten minutes to warm up the coolant enough to > make the defroster blow warm air? Otherwise, the windshield and windows are > just going to fog up completely about a mile from where you start? If the > engine is running, couldn't we generate enough electricity to power a > heater pointing at the windshield for long enough for the engine to warm > up?! > > My guess is no. An idling engine doesn't put out all the current the the > alternator can produce. I'll have to run the numbers but even if it's 15 > amps (which I doubt) that's only 180 watts. Compare that to a space heater > at 1500 watts. It would be a drop in the bucket. > > Install a tank heater and plug it in at night. The engine coolant will be > warm in the morning and take less time to get up to temperature. You will > get warm air from the vents right away, albeit not enough to do much > warming of the car. > > Jim. > > > I think Jim's right. Running a 1500 W heater electrically in the car > would require 125 amps. Many cars have less than 100 amp alternators. I > think my 81 Mercedes has a 55 amp alternator or something. I think more > modern cars may have a 90 amp unit or something, but I'm not a mechanic. I > don't think they have to be running at full speed, but they don't do much > at idle as Jim said. I did put a space heater in a car once with an > extension cord on a very cold morning when the car heater was > malfunctioning. Even with that, it took 10 - 15 minutes to get the car > toasty, although I think I had it on low power. Someone told me once that > the climate control system of a car has to be as powerful as the heat pump > on a small house. It takes a surprising amount of energy. Not only that, > the manufacturers are under tremendous pressure to meet emissions > requirements. My mechanic said they essentially build the car around the > emissions system. So, I'm speculating that they want to warm up the engine > and catalytic converter as quickly as possible to minimize emissions rather > than sending heat to the heater core. Having said that, it should be > possible to send enough instant heat to the defroster to defrost and defog > the window, maybe a 20 amp circuit providing 240 W or something. > > Sincerely, > > Ron > > -- > > (PS - If you email me and don't get a quick response, you might want to > call on the phone. I get about 300 emails per day from alternate energy > mailing lists and such. I don't always see new email messages very quickly.) > > Ron Frazier770-205-9422 (O) Leave a message. > linuxdude AT techstarship.com > > > _______________________________________________ > tech-chat mailing list > [email protected] > http://lists.linuxmoose.com/mailman/listinfo/tech-chat > >
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