Cigarette/Cigar Lighter Amperage?

Frank.Rizzo

New Member
Dec 23, 2003
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Central Oregon
I know it takes a 20amp fuse, but does anyone know what the actual amp output is for the cigarette lighter? I want to hook up an accessory wire off the cigarette lighter and can test the voltage (it's 14.5 VDC), but don't have an amp meter to find the real amperage.
 
Since the circuit is fused for 20 amps, one could assume it can handle that much current (and generally circuits like this are not configured for burst outputs, so the wiring should be able to handle a continuous load).

One might assume you can handle about 240 watts on the entire circuit.

It sounds like you have a DMM. If so and it can handle a 20 amp load, put the meter in series in the circuit and depress the lighter and note the peak reading. That would give an idea of how much power the lighter element draws.

Good luck.
 
Since the circuit is fused for 20 amps, one could assume it can handle that much current (and generally circuits like this are not configured for burst outputs, so the wiring should be able to handle a continuous load).

One might assume you can handle about 240 watts on the entire circuit.

It sounds like you have a DMM. If so and it can handle a 20 amp load, put the meter in series in the circuit and depress the lighter and note the peak reading. That would give an idea of how much power the lighter element draws.

Good luck.

Hey JT,

I knew you would see this sooner or later . . . I probably should have just PM'd you in the first place! My problem is that I'm installing a little cooling fan assembly that can't handle more than 10.5 amps, so I'm trying to figure out what the circuit provides without just burning up the fans and I didn't want to guess. Maybe I'll try to borrow an amp meter and figure it out next week. Thansk for the help! :nice:
 
Hey brah.

I might not be following (happens more than I care to admit).

Remember, an item only draws what power it needs. For example, you could hook your fan up to a 15 amp circuit or directly to the battery and it will draw the same amount of power (it's like a horse drinking from a large trough or a lake. The horse doesnt drink 100 times more water or drink it faster because the body of water is a lake).

If your fan has a rated spec of 10.5 amps, do you know if that's continuous draw? Some fans can have a start-up draw of 100-300 times their rated-continuous draw (and on the flipside, they become generators when powered-off but still spinning).

In any case Frank, consider using a relay if you want. You can then choose any power source you desire. The chosen power source (i.e., the cigar lighter) will turn the relay on (the draw of turning on a SPDT/SPST relay is about 1/4 amp). Then the fused battery power to your relay will power the device itself.

Alternatively, if this fan will not be used when the HVAC fan is on, that's a 30 amp circuit which could be used. Note that it is only hot with the key on however.

If I totally missed the boat, post up and I'll get it right. :nice:

Good luck with the project. :nice:
 
It'll work fine. The actual lighter draws a lot of current while heating up. I highly doubt a cooling fan will draw more than that thing. I wouldn't worry about it. If it blows the fuse, it's drawing too much and it costs you a couple cents for a new fuse if your fuse cover doesn't carry spares.

Frank Rizzo . . . That name brings back memories, I used to love listening to the Jerky Boys.