auto 12v laptop power

abrady · 05-04-2009, 07:22 AM

I have an older laptop that does not operate on batteries, 110v adapter only.
If I determine the polarity of my adapter, and I make an auto (cig lighter) connection, will the high auto amperage make laptop toast?

farslayer · 05-04-2009, 07:39 AM

could always use an inverter then plug the laptop power supply into the inverter..

http://shopping.yahoo.com/p:Targus%2...ter:1991536822

pixellany · 05-04-2009, 07:50 AM

The power adapter for my HP puts out 19volts (Not sure if AC or DC without checking). Car is 12 Volts DC, so a convertor would be required.

So, the first thing you need to know is the VOLTAGE put out by the adapter and whether it is AC or DC.

The current (amperage) is a derived property. A car battery is capable of supplying several hundred amps of current, but the actual current depends on what the device load is.

pixellany · 05-04-2009, 07:51 AM

Quote:

Originally Posted by farslayer

could always use an inverter then plug the laptop power supply into the inverter..

http://shopping.yahoo.com/p:Targus%2...ter:1991536822

That is indeed probably the safest and easiest solution........

farslayer · 05-04-2009, 10:42 AM

Now if you were building a mini-itx PC for use in the car, for say a Media player, to play all your .ogg files...

you could get a DC to DC converter 12vDC to ATX
http://www.bigbruin.com/reviews05/re...picopsu&file=1

Slick little units.

abrady · 05-05-2009, 06:09 AM

I thank all you folks. I was unclear (what's new).
My adapter puts out [12volts, ?ma.] and I wanted to hook direct to auto. The laptop is 12v DC as is the car. Pixellany, am pretty sure your unit is 19v DC.
Thanks again.

abrady · 05-05-2009, 06:14 AM

Farslayer: I see the logic (and safety!) of your approach. this Old (originally Win 2K) isn't much. I would not try this with a good one. thanks for your time.

farslayer · 05-05-2009, 07:26 AM

We understood your intention of tying directly into the Vehicles DC power, but were offering safer alternatives. Hate to see good kit go to waste.

Keep in mind Automobile power is NOT 12v DC.. Mine is around 13.5-13.8v when the vehicle is running and there is noise on the line from the ignition system and alternator.. At the very least you should construct a 12v DC Regulator with a noise filter, so then at least you know for sure what you are pumping into the laptop..

Best of luck.

michaelk · 05-05-2009, 08:02 AM

The power supply might have the output current rating listed on its sticker. You should put a fuse on the input however the problems lies in what voltage variations the computer can handle. Nominal alternator voltage output is ~13.8 but it can peak as high as 14.5. Without knowing if any internal components work directly off the 12VDC I would be reluctant to plug it directly into the cig lighter.

pixellany · 05-05-2009, 02:51 PM

Quote:

Originally Posted by farslayer

At the very least you should construct a 12v DC Regulator with a noise filter,

and a current limiter or fast-blowing fuse.......

But a regulator to take you from ~14volts to 12volts takes a little care to design.....

Did someone say "get an inverter and use the exisiting laptop power adapter." .....

alanabbott · 05-05-2009, 05:54 PM

There are plenty 12V input notebook power adapters with up to 4.5 A output, in the market place, just google-it and avoid roasting you notebook. (price range of u$s 30)

pixellany · 05-06-2009, 02:58 PM

There are also plenty of 12DC to 110VAC inverters--starting at around $30+. If you get the inverter, it will maybe be useful for other things than just running the laptop.

abrady · 05-07-2009, 06:02 AM

All good input. Many thanks, now perhaps we should get on to real linux issues?
I get so much information from your answers to others questions I don't want to disrupt that further. (So much new turf for me to cover).