How strict is the 120W limit on most cars' outlets?

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Doppel

Lifer
Feb 5, 2011
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I am going to buy a power inverter. It seems a lot of cars have a 120W limit on their outlets. Is this strict? Will the fuse go even with a temporary peak of 150 or 200?
 

Gillbot

Lifer
Jan 11, 2001
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You will probably pop the fuse, depending on how "temporary" that peak is.
 

Gillbot

Lifer
Jan 11, 2001
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Why are there 300W inverters?

There are much larger than 300W inverters out there. Just get one that satisfies your load requirements and not even worry about the rest IMHO. I have a 120w built into the dash of my truck, a 300w cigarette plug in one and a 2000w I keep that hooks to the battery directly in case I need to run power tools or something.
 

Throckmorton

Lifer
Aug 23, 2007
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There are much larger than 300W inverters out there. Just get one that satisfies your load requirements and not even worry about the rest IMHO. I have a 120w built into the dash of my truck, a 300w cigarette plug in one and a 2000w I keep that hooks to the battery directly in case I need to run power tools or something.

Yes but I mean why are there 300W cigarette lighter invertors if most cars only support 120W output? Or are we talking about the newfangled cig outlets that don't allow you to use a cigarette lighter therefore the manufacturers cheaped out with wiring?
 

olds

Elite Member
Mar 3, 2000
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Yes but I mean why are there 300W cigarette lighter invertors if most cars only support 120W output? Or are we talking about the newfangled cig outlets that don't allow you to use a cigarette lighter therefore the manufacturers cheaped out with wiring?
Unless I am missing something, the car isn't outputting 120w. The inverter is.
 

MrPickins

Diamond Member
May 24, 2003
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Unless I am missing something, the car isn't outputting 120w. The inverter is.

The power has to come from somewhere...

As for the 300 watt inverters, they're probably only for use in cars that actually have a lighter, not just a power port. My 99 Ranger has a 25A fuse, IIRC. My wife's 2012 Mazda3 has 15A fuses.
 

Gillbot

Lifer
Jan 11, 2001
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Unless I am missing something, the car isn't outputting 120w. The inverter is.
Yeah, I'm not following you either...... Probably as stated below though. Older cars had higher amperage for an actual cigarette lighter which can be many many amps allowing higher wattages.
The power has to come from somewhere...

As for the 300 watt inverters, they're probably only for use in cars that actually have a lighter, not just a power port. My 99 Ranger has a 25A fuse, IIRC. My wife's 2012 Mazda3 has 15A fuses.
 

phucheneh

Diamond Member
Jun 30, 2012
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12v x 15a = 180w (or a little over 200w if the car's running)

That's probably a good pair for something rated at 120-150w. I'm not sure what efficiency is like on those small units.

A lot of cars now have more than one 12v outlet on the same circuit, though, often protected by a 25 or 30a fuse. So you've got quite a bit more room, as far as the fuse is concerned...those are still some awful small wires, though. I doubt anything has bigger than 16ga feeding the outlet.

I use my outlet with a cheapo inverter to charge my laptop, run a drop light, and other things...but I'm only ever doing one of them. If you want to plug in all kinds of crap at once, I's say it's worth wiring in a dedicated unit.
 

LTC8K6

Lifer
Mar 10, 2004
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The built in 115V outlet in my Jeep is limited to 150 watts.

The three 12V outlets each have 20A fuses.
 

phucheneh

Diamond Member
Jun 30, 2012
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The built in 115V outlet in my Jeep is limited to 150 watts.

The three 12V outlets each have 20A fuses.

Yet more proof that Chrysler is completely retarded.

A 20a device designed to plug into a cigarette lighter seems pretty much nonexistant.

...might be more common than a household device that consumes less than 1.3a, though.
 

Doppel

Lifer
Feb 5, 2011
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What are you plugging in that has a 150w peak?
No idea, but as another mentioned it's possible now to get pretty powerful ones that go to the cig lighter, not the battery, and I expect a lot of them would blow the fuse.

I should probably check fuse size, but my vehicle says 120W combined on all outlets.
 

olds

Elite Member
Mar 3, 2000
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The power has to come from somewhere...

As for the 300 watt inverters, they're probably only for use in cars that actually have a lighter, not just a power port. My 99 Ranger has a 25A fuse, IIRC. My wife's 2012 Mazda3 has 15A fuses.

Yeah, I'm not following you either...... Probably as stated below though. Older cars had higher amperage for an actual cigarette lighter which can be many many amps allowing higher wattages.
My bad. The word outlet is right in the title but I thought the discussion was about the output from the inverter. :oops:
 

LTC8K6

Lifer
Mar 10, 2004
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Yet more proof that Chrysler is completely retarded.

A 20a device designed to plug into a cigarette lighter seems pretty much nonexistant.

...might be more common than a household device that consumes less than 1.3a, though.

Actually, I think there are quite a few items, especially in the RV/trucker world. Coffee makers and such. Lots of appliances.
 
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