Feeding my laptop with 12v DC

[thalassobiote]

Hello mates, I watched out for threads about this same topic but could not find any.

I am planning to set an old laptop which is going to be used as a nav station.
I did that already years ago for a friend's boat. We bought an old HP Compaq and everything was smooth and easy with Opencpn etc.

I wanted to bypass the 110/220v power supply so we tried to power the laptop with a multi voltage power supply set to 19v (powered by the 12v battery). We cut the original plug on the HP power supply and tried to give straight 19v to it.
I remember the plug had three contacts on it, meaning three wires came from the 110/220v power supply. Believe or not I was not able to define the couple of wires to be used for powering the laptop. Only one of the three was clearly defined (as a negativs if I remember), the other two giving weird signal to my multimeter (something like AC if I remember).

QUESTION: before buying a laptop for the purpose I'd like to know: any of you know about this strange features of a HP power supply?

I still would like to bypass the 110/220v thing!

[Pete7]

Dell as well, if I remember correctly the laptop knows if you are using a genuine manufacturers charger or not from the signal on the third wire. You get a snotty message on a Dell telling you off.

I am currently using a £20 charger on board which has the third connection. Any chance you should look again at a generic charger. Alternatively look for a car charger for the laptop on e bay.

[Suijin]

I bought a charging cord for my MacBook that has Apple's proprietary mag connector on one end and cigarette lighter adapter on the other. Works great.

I'd assume that similar are a available for any PC laptops with proprietary plugs.

[sy_gilana]

We use one, and the BIOS on some machines are programmed to look for the "correct adapter, and it will slow down the processor if you use a "non-original" adapter.

Cheap ones are available on Amazon.com, or eBay, and Dell make the 12v adapters too.

Under windows you can run a program, rightmark, I think, or like us under linux, you can tell the manufacturer to take a walk, and run the processor any dang speed you like.

[liveaboard60]

Most laptops offer power adapters which run off of 12vdc.. You might look to see if there is one for your model of laptop..


flk k

[Sailorlady323]

Bought a power supply 12 volt on line.Readily available. Plugs into lighter receptacle.
Straight 12 volts. Eliminated need for inverter use.
Very happy.

[briblack]

Lund Electronics makes 12V chargers for the common laptops. We went that way. And with a usable, 3-year warrantee!

[Rock-Head]

Originally Posted by thalassobiote

Hello mates, I watched out for threads about this same topic but could not find any.

I am planning to set an old laptop which is going to be used as a nav station.
I did that already years ago for a friend's boat. We bought an old HP Compaq and everything was smooth and easy with Opencpn etc.

I wanted to bypass the 110/220v power supply so we tried to power the laptop with a multi voltage power supply set to 19v (powered by the 12v battery). We cut the original plug on the HP power supply and tried to give straight 19v to it.
I remember the plug had three contacts on it, meaning three wires came from the 110/220v power supply. Believe or not I was not able to define the couple of wires to be used for powering the laptop. Only one of the three was clearly defined (as a negativs if I remember), the other two giving weird signal to my multimeter (something like AC if I remember).

QUESTION: before buying a laptop for the purpose I'd like to know: any of you know about this strange features of a HP power supply?

I still would like to bypass the 110/220v thing!

Crux of your issue is the pc wants 19v and you're only giving it 12. Step-up transformer is what you need there.

Sent from my SM-N900V using Cruisers Sailing Forum mobile app

[sailorchic34]

One thing to watch out for with 12V laptop chargers is current draw with the typical Cig adapter. I melted several as my HP laptop can pull over 10 amps at 12.4V (morning) when the laptop battery is at 10%.

My solution was to hard wire the 12V adapter to the panel breaker. Then no more melted plastic or fire issues.

[PuttingDoctor]

Originally Posted by Pete7

Dell as well, if I remember correctly the laptop knows if you are using a genuine manufacturers charger or not from the signal on the third wire. You get a snotty message on a Dell telling you off.

I am currently using a £20 charger on board which has the third connection. Any chance you should look again at a generic charger. Alternatively look for a car charger for the laptop on e bay.

HP make an adaptor with a cigarette lighter plug. Not sure the availability but I'd you PM me I know I still have it. The computer while still in my possession hasn't been powered up in a few years. Let's make a deal.

[jdazey]

Originally Posted by sailorchic34

One thing to watch out for with 12V laptop chargers is current draw with the typical Cig adapter. I melted several as my HP laptop can pull over 10 amps at 12.4V (morning) when the laptop battery is at 10%.

My solution was to hard wire the 12V adapter to the panel breaker. Then no more melted plastic or fire issues.

Good point. Many thanks.

Cheers,

[Dave22q]

I power my old Dell B830 laptop with a 12v power supply I found on Amazon. Am pretty sure you could find one for just about any popular laptop model. It uses a standard cigarette lighter plug.

[lordgeoff]

Buy a 12V cigarette lighter socked accessory for the Laptop. I know Dell has them. Works a treat for me. Draws pretty much zip power.
I also have put 12V sockets all over the boat and use USB 12V sockets for phones IPad tablets. Etc.

[buzzstar]

Another thought, based upon an almost total lack of specific knowledge. Since laptops run off batteries, might it not be easier to separately charge the battery (having two or even three could be great) and keep the computer protected? I do not know if it is feasible to separately charge a computer laptop battery.

[Ramona]

I use a Toshiba Tectra laptop that uses a step up transformer 12v to 19v. The battery is removed and it is mounted permanently on the chart table with a wooden mounting that utilizes the empty battery compartment. Current draw is much less with out the battery.

Previously I used an older Toshiba that ran fine direct off the 12v ships battery. Its power requirement was 15v but seemed happy with 12v.