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Will Laptop+ Inverter + Cigarette Lighter = Disaster?


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I know this has been mentioned before but I'm going on a camping trip next weekend and I'd like to take my laptop along for the kids to watch movies on.

I've got a pretty low wattage inverter I was going to use. Will the in-dash cigarette lighter be okay? I'm worried the dash will catch fire out in the middle of nowhere with a wife and carload of kids.

 

Also, I've heard of people suggesting to use the "one in the back". Where is this second lighter? I don't think my car has it (2000 OBW).

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The outlet will run the inverter and laptop fine. That isn't too much of a draw. The outlet is fused anyway so if it is too much load it will just pop the fuse. I have an '00obw too; I think I did see another outlet way in the back but I can't remember for sure.

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The outlet will run the inverter and laptop fine. That isn't too much of a draw. The outlet is fused anyway so if it is too much load it will just pop the fuse. I have an '00obw too; I think I did see another outlet way in the back but I can't remember for sure.

my inverter - 400w - has an alarm built in which sounds when i pull more juice than it can put out. occasionally the alarm will sound, but i've never had a problem with the lighter fuse.

 

when i bought it i was worried about the wiring in the car because the inverter came with battery clips and heavy duty wires. have you seen the wires that feed the lighter? they are tiny.

 

W = V x A; 400 Watts = 12 Volts x 33.3 Amps ( i think mine is 400 surge watts, not 400 continuous watts.) what's the fuse on the lighter. my old laptop worked fine at idle, my new one needs the car running a little faster.

 

i read some great advice, here i think, regarding the use of an inverter for lights in your home when the power fails, use the new low wattage flouresent bulbs, you light many more bulbs / rooms than with incandescent.

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I'm not sure what the lighter socket fuse is; probably like 10A or maybe 15A. So it should be able to run say up to a 100W inverter pretty well. Most of the small inverters for laptops are maybe 40-70 watts. A 400 watt inverter, well, that is a little different story when loaded up, and that is why it has clips to hook directly to the battery.

 

Also the inverters are not 100% efficient so they need more input power than the power they are putting out.

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I just checked, my inverter is 150W. Not sure what my laptop draws- its' an older Dell Inspiron P4, the ac adapter for it says 12v / 4.5A, which does not seem like a whole lot. I can tune the laptop down also. Right now it's in performance mode. I think there's a setting for "battery" or energy saver or something like that.

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agree with earlier reply, your cig ligher is fused, so if you over load the circuit, it will simply blow the fuse. There is no concern of starting a fire.

 

The cig style outlet on my 99 Oubback wagon is in the back cargo area on the driver's side wall. It is circular, covered with a plastic cap. Pulling off the cap exposes the outlet. That outlet is great place to plug in my 12V small air compressor that pumps up the tires. I use it for that every few months. You must have the ignition turned on to get power to the outlet.

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150Watts is good to go for a laptop. I did it for a 5000mile camping roadtrip out west last spring and had the same concern. You dont want to use that inverter for anything but a laptop, a battery charger, or similar small device.

 

Yes, the cig lighter has a fuse on it, but if you actually look at the wire to the lighter it is ungodly thin. I forget the gage, but it heats up if you push her. Typical for foreign cars I've found. So just a word of caution, but I really wouldn't worry. Though, I would never even think of running a 400Watt inverter off the cig lighter as stated above. That is downright dangerous, and you even run the risk of messing your ignition relays.

 

I ran a tap off the fuse panel for an additional plug (because I had multiple small devices running) and with a thicker wire and noticed it didn't get warm. Note this would give you the option of running something to the trunk or back seat if you needed it and know how to use the correct gage. (longer the run the thicker required).

 

Probably doesnt apply to you, but if you need to run anything big you need a bigger inverter wired directly to the battery and be cautious to not drain it.

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Also if you're going to use your 12V power outlet(s) often and/or for multiple items, you could install a couple of good quality auxiliary outlets and run them fused right off the battery with nice wire like 12ga or even 10ga.

 

There are a couple OEM Subaru kits available that replace the ash tray with two outlets, or replace the coin holder near the parking brake handle with two outlets depending on what Subaru model you have.

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I use mine for laptop work with no problems, even on the older soobs. The extra draw is an extra load on the system, so it could conceivably shorten the life of your alternator or battery depending how often it's used. Moderate use would be fine, but constant use could affect the life of those components. Someone more knowledgable than myself can comment more about that.

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A portable DVD player costs about $60 and runs right off a 12vdc connector.

 

I know this has been mentioned before but I'm going on a camping trip next weekend and I'd like to take my laptop along for the kids to watch movies on.

I've got a pretty low wattage inverter I was going to use. Will the in-dash cigarette lighter be okay? I'm worried the dash will catch fire out in the middle of nowhere with a wife and carload of kids.

 

Also, I've heard of people suggesting to use the "one in the back". Where is this second lighter? I don't think my car has it (2000 OBW).

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Yes it will be fine. My outback has a second lighter on the left hand side by the jack compartment, not too sure about yours.

 

 

nipper

 

I found it, it's in the back INSIDE the jack storage compartment :banana:

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I run a 300w (peak) inverter. It's powered from the P/O amp wiring. I run a 25a fuse in the "monster" fuse holder under the hood. This means it's wired straight into my batt, but fused for your protection, and "0" guage for her pleasure. I run my Lappy & cell phone charger from it on trips.

 

Unibrook, that depends on the saw's current draw, or power demands. If you have an Amp rating or watt rating, you can find if the 100W will carry it. Remember though that most inverters are rated at PEAK output. They can only sustain peak for a few seconds at a time. After that you let out the magical smoke that makes all electronics operate.

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I want to run a 4" circular saw off of my 2001 Forester. Can I do it with a 100W inverter plugged into the socket in the cargo bay of the car?

 

 

Probably not. If the saw draws even 1 amp (120vac X 1amp = 120watts), you're over the limit, especially when a inverter will add losses from stepping the 12vdc from you car's battery up to 120vac for you tool(s).

 

A useful calculator (there are many out there, just google):

http://www.csgnetwork.com/ohmslaw2.html

 

(on a side note) check out that website's calculator(s) for automotive functions: http://www.csgnetwork.com/automotiveconverters.html :cool: ;)

 

I don't think I've seen a inverter larger than 400watt output for direct plug into a cigarette lighter. Most car manufacturers don't wire and fuse their 12volt plug-ins to carry high power capacity (though a 400watt inverter is fairly substantial to run many things). Power tools tend to draw more amperage than other devices. Any inverters larger than 400watts will usually require direct connect to the battery via aligator clips, or a custom installation.

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You have to be careful though in all that that you don't blow the lighter socket itself. Two times in a row, my dad blew the socket in his 97 Toyota Camry courtesy of a 90w inverter.

 

That's a good point, though with typical car 12volt sockets having a 15amp fuse in the box for that circuit (allowing 180watts) you'd think they would have spec'd the socket itself to handle above that. But never assume..... I'm sure it has something to do with the heat dissipation from the cigarette lighter itself, as to make sure the entire socket body never gets hot enough to start melting the surrounding plastic dash trim :eek: :-p Most of the sockets have a special thermal fuse on their back for that type of protection. Your Dad's may of been more sensitive to that. It took the full output of a 350watt inverter to melt the socket wire on my 96 OB.

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I want to run a 4" circular saw off of my 2001 Forester. Can I do it with a 100W inverter plugged into the socket in the cargo bay of the car?
Highly unlikely that saw draws less than 100W unless it's a rechargeable type and you just want to charge its battery. Look on the nameplate for the device, it should say the power draw. You really need to know the VA (volt-amp) draw of the device (since the motor is inductive, it will require more VA than watts). Also the inverter would need to be able to handle the surge/inrush when starting the motor.
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Highly unlikely that saw draws less than 100W unless it's a rechargeable type and you just want to charge its battery. Look on the nameplate for the device, it should say the power draw. You really need to know the VA (volt-amp) draw of the device (since the motor is inductive, it will require more VA than watts). Also the inverter would need to be able to handle the surge/inrush when starting the motor.

i spent 20 in the construction industry. and back in 1975 all circular saws drew 80% of 15 amps (12.0 amps). that was / is the safety cutoff of a 15 amp house circuit breaker. the breakers had a 80 % max cutoff and wiring had a 133% max (20 amp). so the breaker popped before the wire failed.

 

maybe a rechargeable saw could be used on an inverter, but a standard circular saw uses 1400 watts. no big motors, no heaters, no toasters.

 

although someone makes a small gas powerewd blender for tailgating at your favorite football game.

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  • 12 years later...

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