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Powering a Laptop on 12 volt

For all things Electrical.

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Powering a Laptop on 12 volt

Post by ausyota »

Im setting up a GPS nav setup with a laptop and was wondering what would be the best way to power it.

Is a a laptop cig lighter adaptor a good thing or would I be better off running an invertor and plugging the 240v adaptor into it?

The invertor seems the ass about way of doing it but means I can run other 240v stuff too (not that I ever really need to).

Are the 12v adaptors any good?
How do they convert 12v into 19v?

Does anyone know where I can get a 12v laptop adaptor from cheap?
I saw one in a computer shop on the weekend that was $105 :shock: surely they can be had cheaper than that!

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Post by pcman »

try jaycar for a generic laptop adapter but there not cheap $105 sounds like a good price to me

i paid 130 for a 240v adapter for my laptop :(
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Post by BigMav »

I got a ciggy lighter adaptor to run my laptop but i think that the better option is an inverter off your second battery to run all the time. The problem is when you turn the car off the power is lost to the laptop, the battery on my laptop is stuffed and doesn't last long without power going to it. I've lost waypoints and stuff on oziexplorer a couple of times because i forgot about it. A small 300w inverter doesn't cost much off ebay.
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Post by marin »

i run mine on a 300w inverter, $86 including postage from ebay, just need to run cable from battery, cauz it complains a little bit when trying to charge from the lighter circuit, not enough amps, but it is fine otherwise
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Post by Utemad »

I used to use an inverter but it blew up part way through my trip around Tassie (good reason to carry paper maps too). So I got another inverter from work and even though it is a larger capacity one and supposedly a better brand it won't run my laptop. Just makes the power supply go 'click, click, click". So I bought a 12v laptop power supply from Jaycar.

If you do buy an inverter make sure it powers your laptop first. The cheap ones on Ebay lately have been Jaycar ones anyway so take your laptop to Jaycar and ask to check their inverters with your laptop.

If you have an ABN try using Electus. Same as Jaycar but wholesale prices.

http://www1.electusdistribution.com.au/

Electus wrote:STOCK-CODE: MP3462 RRP: $89.50
Qty 1+ $57.28 Qty 3+ $52.80 Qty 5+ $49.22 +GST

2.9A Laptop Computer Universal Switchmode DC-DC Multi-Voltage Car Power Supply


Electus wrote:STOCK-CODE: MP3466 RRP: $119.00
Qty 1+ $76.16 Qty 3+ $70.21 Qty 5+ $64.26 +GST

5A Laptop Computer 120W Switchmode DC-DC Multi-Voltage In Car Power Supply

Plug this multi voltage car adaptor into your cigarette lighter socket and charge up your laptop computer. Star Burst:
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Post by Tas_Dean »

What voltage is the laptop that you plan to use? IE what does the charger/adaptor say on it for OUTPUT? If your laptop is 15 volt or less, just get a plug that fits the laptop and wire it straight to the battery. A few of my mates have been doing this on boats for about 5 years. One mate of mine has had the one laptop running this way for 5 years, and no sign of damage to the laptop. His laptop is a 15V Toshiba.

Otherwise, I'd run it off a cheap invertor, I can't see the sense on spending the money on an expensive 12v adaptor. I run my 19V laptop from a $50 invertor, it runs fine!

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Post by walker »

It's better not to use an inverter to power your laptop. Without being too technical, most inverters create a "square" sine wave which means you get a lot more heat and the power is not real good for you laptop.

A DC to DC convertor is the best way to go such as people were talking about from Jaycar. You should be able to buy one with multiple voltage outputs so you can use them with different laptops. I picked up mine from a place in Perth on Ebay for $55.
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Post by Tas_Dean »

walker wrote:It's better not to use an inverter to power your laptop. Without being too technical, most inverters create a "square" sine wave which means you get a lot more heat and the power is not real good for you laptop.

A DC to DC convertor is the best way to go such as people were talking about from Jaycar. You should be able to buy one with multiple voltage outputs so you can use them with different laptops. I picked up mine from a place in Perth on Ebay for $55.


Switchmode supplies tend not to worry about square waves, they may get a little hotter, but I've never actually seen any problems. Switchmode supplies don't look for the sinewave, only the frequency change, therefore they generally don't care.

By the way, a UPS is a battery and an invertor!

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Post by pjhsv »

Tas_Dean wrote:What voltage is the laptop that you plan to use? IE what does the charger/adaptor say on it for OUTPUT? If your laptop is 15 volt or less, just get a plug that fits the laptop and wire it straight to the battery. A few of my mates have been doing this on boats for about 5 years. One mate of mine has had the one laptop running this way for 5 years, and no sign of damage to the laptop. His laptop is a 15V Toshiba.

Otherwise, I'd run it off a cheap invertor, I can't see the sense on spending the money on an expensive 12v adaptor. I run my 19V laptop from a $50 invertor, it runs fine!

Cheers, Dean


I'd seriously reconsider connecting a laptop up like this...for the relatively small price for an invertor, a cigarette lighter adaptor, or at the very least, some form of circuit protection, you could save yourself $1000+ on a laptop if your alternator regulator shits itself after a water crossing sometime, and frys your laptop. Hell, you could even make a quick diode protected, regulated power supply using a few diodes, a couple of capacitors, a couple of resistors and a transistor from dick smith for the princely sum of about $6 if you really don't want to spend any cash..
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Post by Ferwoaza »

Though I'd just throw my 2cents in here since I've just done this.

Old Toshiba Tecra 750DVD.

I have a GPS mouse connected to it via the USB port and run Oziexplorer with the NATMAP 250,000:1 Standard Raster Maps.

I use the Cigarette light to 15v (5amp) adapter available from Jaycar, works perfectly. I also have installed a TFT from Jaycar (yes I do work there) and use one of their VGA to video converters to output from the Laptop to the TFT screen on my dash which is wired straight to 12volt from the car.

If you have a dual battery setup (my next project), simply wire in a new cig plug from the second battery and use that for your power requirements, then you can run it all the time with no worries when stopping. I find the battery in the Laptop keeps it going anyway for around 30 minutes (thats what Ive set it too) during stops.

It's a good setup, runs well, laptop sits under my seat all tucked away. Next setup will be to add the new laptop keypads we are getting in a week or two, and using macros in windows, I should be able to control all the functions I want, without having to open the laptop.
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