# laptop charging on 12v?



## chrisgog (May 17, 2005)

As someone who blew a Roberts radio by using wrong adaptor for charging off cigarette lighter can someone tell me if I have to buy a special adaptor for charging up a laptop from cigarette lighter and also digital camera.

Do not want to ruin anything.Not planning to get these expensive inverters really and would prefer to use 12v if possible?
chris


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## sallytrafic (Jan 17, 2006)

Not all 12V equipment can handle the 11-14V swing of your '12V' socket. However plenty of people have plugged 12V stuff into the these sockets and report that they have had no problems.

My camera has a 12V charging lead but there is a series regulator in the plug. I don't think I would trust a laptop to a naked '12V' supply.


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## gm6vxb (Nov 3, 2007)

Maplin have a couple of power supply/ chargers in their range. Have a look at
http://www.maplin.co.uk/module.aspx?ModuleNo=36836&doy=18m3 which is the one I use.
Make sure first though that the unit has the correct plug for your laptop. 
Dell laptops may not work.
Martin.


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## DABurleigh (May 9, 2005)

chrisgog said:


> Not planning to get these expensive inverters really and would prefer to use 12v if possible? chris


One is tempted to ask, why and why, when it is no more expensive, often cheaper, more flexible and often more efficient. However, as long as you appreciate these:
http://www.motorhomefacts.com/ftopicp-385221.html#385221
Doug runs:
http://www.action-replay.co.uk/Computing/laptop_power_adapter.htm
http://www.motorhomefacts.com/ftopicp-385243.html#385243
http://www.motorhomefacts.com/ftopicp-385507.html#385507

Dave


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## 2kias (Sep 18, 2006)

gm6vxb said:


> Maplin have a couple of power supply/ chargers in their range. Have a look at
> http://www.maplin.co.uk/module.aspx?ModuleNo=36836&doy=18m3 which is the one I use.
> Make sure first though that the unit has the correct plug for your laptop.
> Dell laptops may not work.
> Martin.


I use that one aswell. Never had a problem. Forget the invertors!


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## geraldandannie (Jun 4, 2006)

chrisgog said:


> Not planning to get these expensive inverters really and would prefer to use 12v if possible?


Hi Chris

T'other side of the coin here. With my £15 (off Ebay) inverter which plugs into my cigarette lighter, I can charge up my laptop (Apple, so 19V dc or something), our mobile phones, our cameras, iPod and another MP3 player, rechargeable razor, and batteries for portable radio / MP3 speakers, just using the chargers we already have.

See :: this thread :: for some good technical discussion and opinion.

As always, diff'rent strokes for diff'rent folks.

Gerald


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## sailor (Aug 23, 2005)

In answer to the original question different laptops have different requirements. Mine uses input of 20v and 6 amps, 120 watts. No way would that work directly from a 12v socket, but through an inverter it does work sort-of. The inverter really needs to be connected dirctly to the battery as much car or van 12v van wiring will not support 120watts. (which of course is 10 amps at 12v).

Check your laptop power supply, it will tell you what it delivers. If it is 12v and a low enough wattage you might have a chance.


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## geraldandannie (Jun 4, 2006)

sailor said:


> Mine uses input of 20v and 6 amps, 120 watts.


Are you sure about that? 8O

You need to check the laptop itself, rather than the power supply. The PSU is always rated higher than the laptop.

We had the discussion on the thread quoted earlier :: here it is again :: about 'rated' power and actual power.

Gerald


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## johng1974 (Jan 17, 2007)

My desktop doesn't use more than 100W with 3 disks , a power supply (and it's fans) etc.. sure a laptop would be half that or less... ?


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## sailor (Aug 23, 2005)

The laptop itself is also marked as 20v and 6 amps. Certainly the amps will be a max as it will of course vary depending on what is going on at the time.

This also ties in with my inverter experience - the laptop charges OK with the inverter but does not run well when plugged in to the inverter, which keeps cutting out. The inverter is nominally 300w, but the supporting wiring is , I think, 100.

There is a huge difference in the current depending on the power of the processor and other accesories, not especially the disks. Mine is quite old now, its a P4 3.2gh. and it has a separate mobility radeon 9200 graphics card. 

A celeron based system at around 1.5gh will use much less. Not sure about the later dual core processors.

JeffO


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## johng1974 (Jan 17, 2007)

hmm..

I guess the screen must nick a bit of wattage too..


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## chrisgog (May 17, 2005)

Thanks everyone. A simple question has produced some sound advice, Thanks for highlighting other posts Dave.
Will get my techy brain in action and decide what to buy from all this info.
Thanks all
chris


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## rowley (May 14, 2005)

I would definitely go for a pure sine inverter. Then you can safely plug in any 230v item. Subject of course to the capacity of the inverter.


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## geraldandannie (Jun 4, 2006)

sailor said:


> Mine is quite old now, its a P4 3.2gh. and it has a separate mobility radeon 9200 graphics card.


Okay, that's some serious laptop - not your 'normal' £400 job :wink:

My iBook PSU is rated at 45W max, so runs and charges on a cheapo inverter without a problem.

Gerald


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