Can a laptop be charged from the 12v car jack while running?

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tybert7

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I have seen plenty of adapters that will fit the car connection and give a standard AC outlet to plug a laptop power adapter into, but the output voltage seems lower than the amount listed for my notebook. The output from my notebook power adapter reads as :

19.5 V ~6.15 amps
 
It's certainly possible to run it in your car (though it would pose a safety hazard to have it on while driving). You'll just need a power inverter of sufficient wattage to run the laptop. Not all inverters are created equal.
 
No. A world of no. The laptop needs the precise correct voltage, and -- unless your car's manual explicitly states that the accessory socket can handle a long-term 10 amp draw (hint -- it can't, unless it's a work truck, in which case it'll have a built-in inverter and A/C sockets) -- your car's electrical system will gleefully catch fire if you try.
 
That may be too high of a power draw for your accessory socket to both charge and run the laptop at the same time, even if you had a higher power adapter. There is usually a fuse or breaker protecting the accessory socket, and it working correctly will limit draw to 10A/15A/20A before blowing or cutting out, depending on the type of vehicle. A regular passenger car usually states 120W max from the accessory plug.

Trying to use an adapter that doesn't have enough output power could be interesting. :p Its magic smoke may appear.

FWIW, I've used a 135W soldering gun on a 165W max inverter plugged into a regular car accessory plug and nothing blew up. YMMV.
 
As XenIneX said, no. Even though the power brick is most likely auto switching. You'd need about 75Vdc to power the brick. Also, realize that a car's 12V output is actual ~14.5V while running. Still not enough to satisfy the 19V requirement. The current will rise and very possibly blow the fuse. Using Ohm's Law, this is what you'll experience;

Required volts - 19.5

Current draw - 6.15A

multiply the V x A and you get 119.925W

Now replace the 19.5V with the 14.5V you have from the car.

Knowing you need to get 119.925W of power and the voltage is now 14.5;

119.925W / 14.5V = 8.25A

I know that the cigarette lighter in my car has a 5A fuse. Then POW! Now you're thinking,"My car has 12V power points with 15A fuses. I'll be fine" Well that extra current will create extra heat. And we know the heat and electronics don't like each other.

Just my 2¢.
 
Ok, so I think what I hear most of you saying is that I need to wait until I get an electric car before I start using it as a week long battery extender. Let's hope in 6 years they will be under 30k for something that does not look like the leaf with a range of 500 miles.
 
No, just buy a quality power inverter and charge your laptop as you normally would do. I keep a 400W inverter (800W in-rush) in my car for such an occasion.
 
I have a 500w inverter in my car just for such an occasion like when I go camping or cross country driving.
 
When I first worked for Verizon, we were issued Panasonic Toughbooks. We all had the laptops plugged into the trucks all day long. Sometimes more than 10 hours a day. No one's truck burned up. The power packs were vehicle specific as they had 12 Volt plugs. The bricks were standard voltage bricks one would find with any 120 Volt charger. I kept an inverter with the truck since I would use it to charge drill batteries and the one time my vehicle charger for the laptop failed. The inverter kept the laptop going for a few days while the PC support people would issue out a new charger.

For what it's worth, I don't foresee any issue. I would make sure the inverter and brick don't get hot. If you want to get super anal, toss on a quality surge protector before the power brick.
 
shaggy77 said:
When I first worked for Verizon, we were issued Panasonic Toughbooks. We all had the laptops plugged into the trucks all day long. Sometimes more than 10 hours a day. No one's truck burned up. The power packs were vehicle specific as they had 12 Volt plugs. The bricks were standard voltage bricks one would find with any 120 Volt charger. I kept an inverter with the truck since I would use it to charge drill batteries and the one time my vehicle charger for the laptop failed. The inverter kept the laptop going for a few days while the PC support people would issue out a new charger.

For what it's worth, I don't foresee any issue. I would make sure the inverter and brick don't get hot. If you want to get super anal, toss on a quality surge protector before the power brick.
Click to expand...

News Flash! They do make laptop chargers that run on 12V. But the OP does not have one. His intention was to connect 12V from the car directly to the charging plug of the laptop sans power brick.
 
tybert7 said:
I have seen plenty of adapters that will fit the car connection and give a standard AC outlet to plug a laptop power adapter into, but the output voltage seems lower than the amount listed for my notebook. The output from my notebook power adapter reads as :

19.5 V ~6.15 amps
Click to expand...

wra18th said:
News Flash! They do make laptop chargers that run on 12V. But the OP does not have one. His intention was to connect 12V from the car directly to the charging plug of the laptop sans power brick.
Click to expand...

The OP is clearly looking for an AC inverter, not to plug his laptop directly into the lighter outlet sans power brick. His only problem seems to be that he didn't know it was called an inverter.


Honestly, this thread should have ended with my first reply. It contained the information the OP needed, and none of the following misinformation he did not need.
He needs a decent power inverter, that's it. /thread
 
I had a 120W Kensington 12v DC-DC laptop adapter (meh, left it in a rental car in Dallas). Those are great because it's more efficient than an inverter+laptop charger. If the OP hasn't purchased anything yet, it's worth considering.

oh wait, let me do the douche-y thing here because obviously anyone who dares disagree with me or suggests something else has a worthless opinion: /thread :rolleyes:
 
You'll be fine, just make sure you get a power inverter that rated at at least 150W and has some form of cooling, they can run rather hot. I've got 200W power inverter for my setup. Its rather large and has an AC and DC input ports on it.

I can't recall the exact power draw of my old Dell e1705 or Dell 9300 laptops, both with "gaming" GPUs and overclocked, I wanna say they were in the 130 - 150W range. I've used it from South Mississippi to Myrtle Beach, SC continuously (13 hours) with no issues at all.

...and whatever you are doing in your car most likely wont stress the laptop to it's full power draw anyway.
 
pxc said:
I had a 120W Kensington 12v DC-DC laptop adapter (meh, left it in a rental car in Dallas). Those are great because it's more efficient than an inverter+laptop charger. If the OP hasn't purchased anything yet, it's worth considering.

oh wait, let me do the douche-y thing here because obviously anyone who dares disagree with me or suggests something else has a worthless opinion: /thread :rolleyes:
Click to expand...

I find this the most useful post here. I didn't know something like this existed. I've only ever heard of people using power inverters.
 
Yeah they exist and since you aren't wasting power by going from DC to AC and then back to DC, it's a lot more efficient. Never used one though since laptops aren't the only thing I use mine for.
 
There are car chargers you can get for specific models but they wont power the hungrier laptops at full pelt.
 
Op,

Most cars are limited to 15 amps or 180 watts of DC power through an outlet which will be fine for many laptops, but not all laptops. As mentioned you can use a DC charging cable or an inverter. If you go the inverter route I would recommend bypassing the DC socket and hardware it to the 12volt battery system, then you can run a 1000 watt inverter no problem.

Or if you're lucky enough to have a hybrid, like a prius, you can tap into the traction battery that sustain 3000-4000 watts. Then you can go camping and power all your toys for a week on a gallon of gas. :)

Forgot to mention, make sure the inverter is a pure sine wave, and not a modified sine wave. It will cost more, but you must have pure sine wave for computer equipment. Modified sine wave is fine for power tools and such, but now what you need.
 
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I have a toughbook plugged in a kubota rtv utility vehicle 40hours per week. No problem at all
 
Yeah... laptops rarely draw the full 90 or 120 watts from their PSU, especially these days.
You have to be stressing the CPU and GPU 100% with WIFI on... max screen brightness... playing music at max volume...

You can use this http://www.pbus-167.com/ turn off the screen and set everything to lowest power while charging the battery to see how much power you actually need (just to charge the battery) or use a kill-a-watt if you have it

I did some searching and I couldn't find any tests of charging 120 watt laptops but I doubt its very different from 90 watt laptops since the batteries are pretty much the same. I think it will draw under 90 watts probably about 70 while off and charging.

Especially with sandy or ivy laptops that CAN consume over 120 watts, as long as they aren't CF or SLI without optimus or enduro or something, you don't need the original 150, 180 or 230 watt adapter to use it for most tasks. Some HPs and Dells refuse to let you power it on or charge it with a lower wattage, but others even have power plans and software to let you use it with a 90 watt.
 
You will have no problems charging most laptops except for the most power hungry desktop replacements from a cars electrical system. The people talking about lighting your car on fire simply don't know what they are talking about.

You just need the right power adapter to connect your laptop to the output in your car. You can check your manual to see how much current the port can supply in your car, it is more than likely enough. If it isn't the worst thing that will happen is you will get a blown fuse. Your car WILL NOT catch on fire because you plugged in a laptop.

Source: I worked on cars electrical and communication systems for 3 years.
 
wra18th said:
News Flash! They do make laptop chargers that run on 12V. But the OP does not have one. His intention was to connect 12V from the car directly to the charging plug of the laptop sans power brick.
Click to expand...

unless the OP's laptop is designed for it, it wont work.. I have a dell air/car adapter and it works just fine got my Vostro 3460 and 1440
 
Don't you mean unless the charger is designed for the OPs laptop?

FYI Sager/Clevo, MSI and some Toshiba laptops use the same type of chargers
 
You need the right connector and voltage.
 
Erasmus354 said:
You will have no problems charging most laptops except for the most power hungry desktop replacements from a cars electrical system. The people talking about lighting your car on fire simply don't know what they are talking about.

You just need the right power adapter to connect your laptop to the output in your car. You can check your manual to see how much current the port can supply in your car, it is more than likely enough. If it isn't the worst thing that will happen is you will get a blown fuse. Your car WILL NOT catch on fire because you plugged in a laptop.

Source: I worked on cars electrical and communication systems for 3 years.
Click to expand...

^ All correct.

Note: almost all laptops use 19 or 19.5V supplies. Of course plugging in 12v won't work but proper adapters for an input voltage of 12-14VDC do exist. And just about any car can put at least 10A to the cigarette lighter. Some do 15A. 20A is rare but completely unnecessary here.
 
pxc said:
I had a 120W Kensington 12v DC-DC laptop adapter (meh, left it in a rental car in Dallas). Those are great because it's more efficient than an inverter+laptop charger. If the OP hasn't purchased anything yet, it's worth considering.
Click to expand...
That'd be the answer. DC-DC is more efficient. If anyone can find such a device meant for their laptop. It would provide a boost from 12V to 19V for several amps. The laptop can't be directly plugged into the car's 12V because it is not a constant voltage (alternator) and not high enough voltage to both power and charge the battery.

This would do the trick, but it's not setup as a finished product. I couldn't find the kensington one.
http://www.ebay.com/itm/150W-DC-DC-...785?pt=LH_DefaultDomain_0&hash=item415e3f2501
It would need a cigar lighter cord, vented housing, a cord with a tip for the laptop, a multimeter to set it, and probably a dummy load like a power resistor while calibrating.
 
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On the other hand, if someone actually knew how laptop battery charging circuits worked, you could for sure make an external battery charger that ran on 12v. Like this but with 12v input: http://www.ebay.com/itm/External-La...=Laptop_Adapters_Chargers&hash=item56471d7eb3

Someone should take one of those apart already.



Meaker said:
You need the right connector and voltage.
Click to expand...

You need the right brand too sometimes (E G Dell & HP adapters are the same except for the 3rd sensor wire)
 
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When I used to use my old Acer in the car I ended up wiring my own 12V barrel plug for the inverter, I used 10 gauge wire straight to the battery. Didn't have any problems out of it.

Not an option for everyone, but, if you REALLY want to run you lappy all the time.. the only way to go.
 
No one has addressed the real issue. If the DC input asks for 19 volts, do no plug in 12-14 volts as a substitute. The results will be unpredictable. Any thing from not doing anything, to charging only to a certain point, to taking FOREVER to charge, to burning out a DC-DC circuit inside the laptop that draws a whole lot more amps to compensate for the voltage.
 
This is what I was saying, you likely want to match the input voltage, there is a lot of power regulation in a brick for a reason.
 
westrock2000 said:
No one has addressed the real issue. If the DC input asks for 19 volts, do no plug in 12-14 volts as a substitute. The results will be unpredictable. Any thing from not doing anything, to charging only to a certain point, to taking FOREVER to charge, to burning out a DC-DC circuit inside the laptop that draws a whole lot more amps to compensate for the voltage.
Click to expand...

Not to mention there are far worse things on a cars electrical system than the power fluctuating between 12 - 14 volts. I have literally blown up voltage regulators putting boards through the automotive electrical testing. The load dump is particularly nasty (simulates a bad battery connection, if the battery gets disconnected while the alternator is running you get a huge surge of energy) and is usually what makes things go poof. If you don't have something that is designed to be plugged into vehicle power and has the proper front end protection for that power environment you could be inviting trouble.
 
niffcreature said:
On the other hand, if someone actually knew how laptop battery charging circuits worked, you could for sure make an external battery charger that ran on 12v. Like this but with 12v input: http://www.ebay.com/itm/External-La...=Laptop_Adapters_Chargers&hash=item56471d7eb3

Someone should take one of those apart already.





You need the right brand too sometimes (E G Dell & HP adapters are the same except for the 3rd sensor wire)
Click to expand...

I've taken a few laptop batteries apart, and all it was was a bunch of Li-Ion Cells wired in series/parallel to get the required voltage and current ratings (the last one had two banks of three 3.7v "18650" cells to get 11.1v @ 4400mAH). Those were connected to a smart circuit of sort that monitor individual cell voltages, temperatures, and total current output. If necessary, that circuit will disconnect the battery from the outside world (overcharging, bad cell, high or low temperatures, etc). Charging them is controlled by the system's embedded controller and operating system based on output from the battery's smart circuit.

If you were endeavoring enough, you could get a Li-Ion cell charger and mod your laptop battery so that you could replace the cells as you needed.
 
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That smart charger can also kill the battery totally if a cell voltage drops to 0.
 
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