Low power computer for the boat

**Ceasar_Choppy** · 11-07-2006, 08:02 PM

Thought I'd revive the Boat forum with a question or two.

I'd like to build and install a mini-ITX based computer with a 10 or 12" touch screen on the boat. Unlike a car, however, I don't necessarily have the space issues, but I would have the environmental issues.

Comp would mostly be for navigation, (chartplotting and AIS monitoring) and some system monitoring software while underway. I'd also like to run DVDs etc., wouldn't do that very often underway.

My biggest concern is amp draw @ 12v. From what I can piece together after reading through here and other sites is that I'm looking at a 2.5A - 3A draw with the itx and touch screen. With this type of draw, is really worth going this route or should I just get a laptop with a DC-DC power supply and if I want the touch screen, add that to the laptop?

I do some racing and extensive cruising so draw on the batteries without having to charge the batteries every hour is a concern for me. I've got other systems that are already drawing an average of 5 amps which allow me to run for about 24 hours before I need a recharge.

Anyone have any idea what a laptop draws normally for comparison?

Thanks!

**miwise** · 11-11-2006, 11:04 PM

Depends on the laptop. Mine draws around 3 to 4 amps (but that's considering the 15" monitor). Some draw less, some more. Biggest variable would probably be the cpu. AMDs I believe tend to draw more current (at least they used to) than the intel line, but it's not going to be significant. I would probably say at least 2.5 amps, though, if you consider the monitor. The bottom of my laptops say 3.15 amps.

**Ceasar_Choppy** · 11-13-2006, 10:46 PM

Thanks miwise. Hmmm. It is tough to get any info like this for laptops, but I guess I can start based on the CPU.

When you say the bottom of your laptop says 3.15A, what are you referring to?

**terryking** · 03-02-2007, 07:38 AM

Hi Choppy, The continuous power issue is one I am looking at too, in sailing cruising. Do you have any onboard wind or solar power?? You need to actually measure the current drawn by your laptop or ITX. A decent digital multimeter will measure up to 5 to 10 amps (My Elenco does 10). Then you can see what happens as the system slows down / powers down the hard drive etc... Right now I'm looking for info like that on some VIA Mini-ITX boards...
Regards, Terry King ...On The Mediterranean in Carthage

****FOUND this: Take a look at:
http://www.epiacenter.com/powersim/p...mulator_v2.htm
for a 'spreadsheet-like' calculator for the VIA boards...

**jbors** · 03-20-2007, 01:08 PM

Why not to use PDA like AXIM x51v for instance ? It has 640x480 video output and you can use its touchscreen to control things.
Will not be able to use DVD though

**Evergreen** · 03-30-2007, 01:56 PM

What I am finding with my installation is the CPU is only a portion of the power equiation. The more you are hoping to use this computer for the more power it will take. Do you want to watch the occasional DVD, play MP3's, connect to a SSB for email, Satphone, WIFI, cordless keyboard, MUX, AIS, the list goes on. With and AMD Geode 1750 mini-itx board, 120gb laptop drive and 1gb sitck of ram I draw about 3.9 amps. Some of that might come from USB attachments, I am looking into how to power them down with out unplugging them as some will not be needed offshore.

**Extide** · 09-04-2007, 10:50 PM

I just booted up my carpc with my multi meter watching the current -- 2.5A-2.9A while booting up and ~1.6A-1.7A idle/playing music/FMRadio

Its an Intel Pentium M 1.5Ghz
i915Chipset Mobo
1Gb DDR2
60GB 5400RPM laptop HD

I am also running lower than stock voltage on the cpu (~0.86v as opposed to 1.35v)

Not Bad