anyone thought about using a electric car heater/ heaterbox to run the defrost and footwell ? not much room in my car after i installed my ecotec and w/c t5 tranny into my car..only passenger foot well has space left , my thought this would be easier than trying to design a heater/ heater box system tapping into the coolent system.
Years ago I tried a 12v defroster in a VW beetle. It did about as good of a job as a medium size cat farting on the windshield. That was 30 years ago though, there must be something good out there now.
There just isn't enough electricity available in your car to do the job. Suppose your alternator can make an extra 30 amps beyond what you're using now. At 12v, that gives you 360 watts. For comparison, the little 120 V electric space heaters are about 1800 watts. So you could maybe get 1/5 the heat of one of those. It's just not enough.
There probably isn't enough power to compete with hot water, but maybe worth experimenting. Many newer cars (especially higher end diesels) use electric heat modules to start warming up the cabin while the engine takes its time getting to temperature. 2012 tdi Passats had this as standard, others with automatic climate control may as well.
Better to heat the humans directly with heated seats. Doesn't solve the windshield problem, though.
Using hot water for heat has an elegance to it - that's wasted energy otherwise. But it's fairly flexible, so I'd keep working on trying to package that. Maybe you could trunk mount a heater and run ducting forward or something similar. The "heater" in an air-cooled VW bux is a duct that runs the length of the van, underneath, and carries warm air from the engine bay. You couldn't do any worse :)
Find the Binky episodes where they designed the airbox. I don't think you would need it to be as complicated as what they did but may give you some ideas for packaging.
I did one of these. Pretty small, the fan is a bit week, and the speed control let out the majic smoke after about 30 mins of use. I just put it in a switch. Anything less than full blast was useless for air movement anyway.
The one I had was not 3 speeds, it was fully variable.
Kubotai said:There just isn't enough electricity available in your car to do the job. Suppose your alternator can make an extra 30 amps beyond what you're using now. At 12v, that gives you 360 watts. For comparison, the little 120 V electric space heaters are about 1800 watts. So you could maybe get 1/5 the heat of one of those. It's just not enough.
There are commercially available electric heaters out there, but as said they don't have much power. Here's one, it's only $50 but it's also only 300 watts. https://www.grainger.com/product/33NU85
The rear heater/blower combo used in minivans and suburbans is something to look at as they are compact
Heated seat covers , or 12v blanket ?
or a German Eberspacher gas heater
There are quite a few electric heater/demister options out there. Not much in the way of wattage but they are similar to this
https://www.demon-tweeks.com/us/demon-tweeks-12v-600w-ducted-electric-cab-heater-tsddech/
110CFM and 600 watts isn't going to warm you up to quickly but it should keep the windscreen clear.
If you find the right alternator you may get the power you need. I'm thinking about my buddy's 74 T'Bird ( It hasn't been around for over 30 years) that monster had some weird set up for defogging that made for super expensive windows and required lots of electricity. The alternator had a 120 volt plug on the back.
Our Tesla has a resistive heater and it pulls enough power to noticeably affect range even with that monster battery. Toasters just aren't a good way to heat air.
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