The heater core in my truck needs replaced and I might not have time to change it out before winter. I was wondering if I could run two 12v heater/defrosters for the windshield or if that would be too much voltage for the cigar lighter and 12v power point? the 12v defrosters are 180 watts each.

 

Let me know how that works. I don't have heat in my truck. What a pain. I think my blend doors are stuck. The two heaters will provide minimal heat to you. I'm not sure if the cigar fuse will handle two though. It is not the voltage that will increase with two heaters but the amperage. You may have to wire up one on the factory cigar fuse and wire up a separate one that hooks up to the battery with 12 gauge wiring and a 20 amp fuse.

I know its been getting colder here. I don't even care about being able to adjust my heat to cold. I just want the blend doors stuck to heat lol! I even thought about buying a mr heater propane indoor heater. But it is a high risk to use inside a vehicle I'm sure lol. The cold is just driving me nuts

 

Okay I just did the math. Remember voltage x amperage = watts.
So 180w ÷ 12v = 15 amps. (12 volts for battery voltage with engine off)

And at highest battery voltage 180w ÷ 15 v = 12 amps.
So you would be safe with a 20 amp fuse to each heater.

Also how are you so sure your heater core is inop? Maybe it is just clogged with sludge? Or another problem

 

I smelled antifreeze thru the vents so I bypassed heater core and smell is gone.

 

You'll freeze your butt off.

Go get a 200 watt light bulb and leave it turned on in your truck on a cold overnight and see what difference it makes.

 

I tried one of those heaters in my VW for defrost . A waste of money . Cleared a 4" circle and no more . I ended up repairing the defrost channels . If you know how air cooled VW's were , you know why I tried the electric one !