How do car cigarette lighters work?

[everybest]

Anybody know how these things work? I think they heat up even when the car is turned off; does that mean it doesn't use any batteries?

 

[belliott4488]

No - it does use the car's battery - that's why it only works (in most cars, anyway), when the key is in the "Accessory" position so that the lighter is powered. I don't know if maybe some cars are wired so that it's always connected. In any case, it definitely doesn't work if your battery is dead.

 

[Dr Transport]

Mine works when the car is off, I use it all the time for charging my cell phone.

 

[everybest]

I actually don't have a lighter myself, and but my cell phone charger doesn't work when the car is off. My friend says his lighter works when the car is turned off though.

 

[belliott4488]

I don't even have a cigarette lighter any more - I have 12V accessory outlets, and now that you mention it, I think they might work in my 2006 Honda Element with the key out, but in my 1997 Honda Prelude, I have to turn the key to the accessory position to charge my cell phone.

I wonder if it was considered dangerous to have "live" outlets when there were hot little ignition devices plugged into them, but convenient to have them now that we're more likely to charge cell phones than to light up a smoke. (?)

 

[Shahil]

It's purely car dependent and works in the same way as your radio does. I wired my radio so that it works even without a key whereas most only work when the key is in the ACC position. My lighter though (I have a Fiat) doesn't work if the car is off. I'm guessing you can just refer to the complete manual for your car (not the one that comes with it! A technical one) and then change how it acts if you desire. I'm not sure what it will do for the warranties though

 

[Integral]

My 06 Chrystler has 1 outlet always on, another switched. My other car can be configured either way, depending on which slot the fuse is in.

 

[Shahil]

Nobody here actually has addressed how these actually work! I'm guessing it works similar to a bar heater at home - electrical energy to heat energy via those filament type things inside the lighter. Quite simple really!

 

[K.J.Healey]

Yes, it is 12v. The cigar heater, you push in so the ends make contact with the leads, it goes through a filament wire that heats up due to the electrical resistance.

Some cars are on the battery, through a fusebox. Others are on the accessory circuit, where they only work if key is on.

 

[binzing]

The bloody thing works like a coil! Hook up a wire to a 9V battery and it will get hot, there's your answer.

 

[Danger]

They also have a thermostatic system that trips a spring to pop them out once they're hot.

I remember when I took a nap in my '66 Falcon. I awoke in serious pain, only to realize that my knee had been pressing the lighter into its socket. Since it couldn't pop out, it heated up to the point that the plastic knob had melted itself into the fabric of my pants.