Building a 12v heater for my car

Join the discussion
Ask a follow-up here, or get your own question answered by working scientists, mathematicians and engineers — people, not an autocomplete.
Real named experts · corrections over time · the nuance an AI answer skips
1 reply · 4K views
glhx
Messages
1
Reaction score
0
I am trying to upgrade my antique car while still keeping the factory look

The rear defroster is a blower motor that sucks in cabin air and blows it onto the back window. The air in the cabin has to get warm before the windows will defog.

I am thinking of helping that a little by installing a 1 to 2ohm resistor rated at 200 watts. It will run around 7 amps and will use 12 gauge wire. The blower will blow air over the resistor and heat the air.

Will this work?...the only thing i don't like is how big the resistor is...its 7x3 inches

i really would like something to do the same job at 4x1 inches as space is limited or really as small as i can get and still have some good heat...im replacing the hose that goes from that blower motor to the duct work with metal pipe...so all of it needs to fit into that space

is there any other more compact way to do this that i haven't thought of?

i did find something like this
http://sunelectricheater.com/ that was 1/8 inch wire that got red hot to 1400°F need something like that that gets to 150°F
 

Attachments

  • rear Defroster1.JPG
    rear Defroster1.JPG
    16.7 KB · Views: 598
Engineering news on Phys.org
you might try a little Halogen 12V 100 watt lamp, or a couple 50's. they're easily replaced and you can get sockets for them... look in lighting dept at hardware or auto parts store... they sell them for closets and off-road lights.

but put in some precaution against fire if your air intake gets blocked. fusible link?