cancel
Showing results for 
Search instead for 
Did you mean: 

Battery powered PC?

Community Veteran
Posts: 14,382
Thanks: 713
Fixes: 10
Registered: 01-08-2007

Battery powered PC?

Anyone know of small but functional PC setup that can run of a 12V car battery for say a week or even two?
I'm looking to put one in a remote location that has no power. It doesn't need to be anything fancy, doesn't even need a monitor or anything in truth, just a bare headless unit that I can plug the odd USB device into and access it remotely via a LAN or 3G connection.
Anyone know of anything?
I need a new signature... i'm bored of the old one!
24 REPLIES
Community Veteran
Posts: 17,766
Thanks: 1,603
Fixes: 19
Registered: 06-11-2007

Re: Battery powered PC?

Any PC can be used, depending on the Power rating of the PC.... you will need to have an Inverter, similar to those featured on this page
http://www.maplin.co.uk/search?criteria=inverter
However.... you WILL need a HEAVY DUTY battery to be able to run the PC for any length of time...
How long do you intend to have it running ? Will you be able to replace the battery with "like for like".... i.e.  one in service and one on charge...?
The alternative would be to use a cheap secondhand Laptop, which would draw less current from the  battery, thus making the battery replacement period longer.....
Community Veteran
Posts: 38,460
Thanks: 1,030
Fixes: 62
Registered: 15-06-2007

Re: Battery powered PC?

Just buy a car laptop power adapter and a dead cheap laptop or notebook
You may need to parallel a number of batteries to get the life
Community Veteran
Posts: 14,382
Thanks: 713
Fixes: 10
Registered: 01-08-2007

Re: Battery powered PC?

Quote from: shutter
The alternative would be to use a cheap secondhand Laptop, which would draw less current from the  battery, thus making the battery replacement period longer.....

I also wondered about this as I have a couple of old dead laptops upstairs (dead HDDs) which would be perfect for the job but there is no way I could squeeze that amount of life out of a laptop battery.
So, is there a way to get a laptop to run from an external battery without an invertor? (I don't want to use an invertor due to the wasted energy). I was hoping to find something that could just plug in somewhere and be connected directly to the 12V.
@OldJim, yes I always have a spare car battery floating around somewhere and if need be, I can obtain more of them but its the actual connection to the computer itself without an invertor that concerns me. Ideally I need battery life of about a week to two weeks.
Basically I need to monitor a site remotely via a camera and thought a webcam would do the job. Then by USB I can also activate a door lock via a usb switch card I have.
I need a new signature... i'm bored of the old one!
Community Veteran
Posts: 17,766
Thanks: 1,603
Fixes: 19
Registered: 06-11-2007

Re: Battery powered PC?

As old jim says,.... a car laptop power adapter would suit.... instead of the "cigar plug" you just need to make sure which is the Positive lead, and clamp it onto the positive side of the battery..
Two car batteries, (one on service, and the other charging)... but you would need to visit them every 4 hours or so, to make sure they were still powering the laptop... Not sure how much drain there would be, you would need someone to do the maths for you... and that would give you an idea of how long you could leave the battery running the laptop before needing to change them over....
VileReynard
Seasoned Pro
Posts: 10,980
Thanks: 265
Fixes: 11
Registered: 01-09-2007

Re: Battery powered PC?

You could try one of these http://en.wikipedia.org/wiki/Raspberry_Pi when it comes out.
Power consumption is 2.5W, so a 12v battery is ample.
It's not a very powerful PC - but you could possibly use its USB connection to drive a relay to switch on an inverter.

Community Veteran
Posts: 17,766
Thanks: 1,603
Fixes: 19
Registered: 06-11-2007

Re: Battery powered PC?

Just a point, regarding the 12v car adapter... best thing is to google your laptop make.... and check that the power requirements for the laptop before you make a purchase....
My Dell laptop runs on 19.5v at 3.3 amps.... ( you can also find this info on the back of the mains supply adapter block).
You then need to make sure your car adapter can deliver the same voltage and amps....
Also check the size and shape of the power connector plug/socket on the laptop....
My laptop has the "normal" round type, but my wife`s Dell has a octagon shape and is larger than mine ......
pierre_pierre
Grafter
Posts: 19,757
Registered: 30-07-2007

Re: Battery powered PC?

I have a 12V car/Plane block that outputs up to 24V for laptops. Its a NIKKAI  A56HY input 12V @ 14A, output 15 to 24V @5A
My Asus netbook takes 19.5V at 2.1A
thought that number looked familier it Maplin at £19
Midnight_Caller
Rising Star
Posts: 4,143
Thanks: 7
Fixes: 1
Registered: 15-04-2007

Re: Battery powered PC?

Quote from: A
You could try one of these http://en.wikipedia.org/wiki/Raspberry_Pi when it comes out.
[Snip]

Thanks for the link wen the Raspberry Pi comes out I will be buying 1 or 2 of them
alanb
Grafter
Posts: 459
Registered: 24-05-2007

Re: Battery powered PC?

Sprite, a vehicle computer DC PSU should be a good match with car batteries. I don't mean a laptop adapter, but a proper ATX compatible PSU with a 12v or 24v input. See here for examples: http://www.mini-itx.com/store/?c=10#int
These types of PSU normally have lower wattage ratings than desktop PSUs, but will be enough to power a basic PC. Expecially if you use them with something like a mini-itx motherboard. The Jetway JNF94-270 motherboard, for example, has an idle consumption of only 16 watts rising to about 25 watts peak consumption. I run a similar board with a hard disc and slimline laptop-style DVD on a 60 watt PSU.
Another good site for such components is www.linitx.com
alanb
Grafter
Posts: 459
Registered: 24-05-2007

Re: Battery powered PC?

I forgot to mention that there are also mini-itx boards with onboard PSU circuitry that just have to be supplied with 12 volts.
Community Veteran
Posts: 14,382
Thanks: 713
Fixes: 10
Registered: 01-08-2007

Re: Battery powered PC?

@alanb: Any idea of the lifespan of one of those running from a 12V car battery? - Any chance of getting a week out of it?
I need a new signature... i'm bored of the old one!
alanb
Grafter
Posts: 459
Registered: 24-05-2007

Re: Battery powered PC?

I've never tried doing it, but I doubt you'd get much more than a day from one car battery. I'm no expert, and the theoretical calculation of battery duration is not straightforward. However, a very rough calculation would be to divide the current drawn by the computer into the battery's Ampere-hour rating to get a crude estimate of the number of hours of available battery life.
For example, if the PC consumed an average of 30 watts: that is 2.5 amps at 12 volts. A typical car battery is rated at 40 or 50 A-h: 40 divided by 2.5 is 16 hours, 50 divided by 2.5 is 20 hours. A diesel car battery might get you more than 24 hours. A golf buggy battery rated at 120 A-h might last 48 hours under the same conditions, but would be expensive.
My understanding is that the A-h rating changes depending on the current consumed. If you discharge a battery slower than it is designed for, the A-h rating can actually increase, but then the rates of internal self-discharge can become more important.
If your application would allow you to shut the PC down (by suspending/hibernating the box perhaps), the battery life could be extended significantly. Incidentally, I think it could be possible to get the average power consumption of a computer down to less than 20 watts with the right motherboard and using a large memory card as a disc drive. Maybe a lot less with a SBC like a Gumstix, a Beagle Board or a Cotton Candy stick. None of which I have ever used so, I can't offer any experiences sadly.
Community Veteran
Posts: 17,766
Thanks: 1,603
Fixes: 19
Registered: 06-11-2007

Re: Battery powered PC?

On the other hand.....
instead of using the "normal" heavy duty * car battery, you might consider purchasing what is known as a "leisure battery".... which is designed to power caravan lighting and similar low power requirements, therefore more "life" in the available ampere hours...
* Heavy Duty - this refers to the "duty" called upon by the vehicle`s starter motor.... and not the length of life in the battery...where the starter motor requires a significantly larger current drain at the start of the "duty" cycle...

whilst this page is one of  the pages you get when you google "leisure batteries" it is given as a guide.... click on the "go" beside each battery to see the prices.
http://www.advancedbatterysupplies.co.uk/lucasgelleisuremarinebatteries.html
whichever "supplier" you choose from those given by google, there is no reason why you could not contact them and give them your requirements to see what they recommend.... Wink
VileReynard
Seasoned Pro
Posts: 10,980
Thanks: 265
Fixes: 11
Registered: 01-09-2007

Re: Battery powered PC?

You could always stick a big solar cell on the roof to trickle charge your battery...