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Old 14-12-2008, 07:02   #1
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Anyone using a low power draw laptop?

Hi all! I would like a laptop that I can run off 12VDC, and has a low amp draw. Ya know... something with a giant screen, all the bells and whistles, can edit video, chart, and play DVDs, but still draw .5 amp. Seriously though...anyone out there have a newer model that is low draw? Thanks, Chris

PS; I have an inverter, but I don't want to run it for this purpose...
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Old 14-12-2008, 08:56   #2
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I don't know of anything that will draw as little as 500mA apart from a PDA. I did a survey on machines that operate from 12 Volts and most draw about 3 Amps. I settled for an Asus Eee PC 900 and have loaded Maxsea 10 navigation software on it + CM93 charts covering the whole world. I am planning on using a separate larger LCD monitor for watching videos or a 10" LCD for use in the cockpit. I already have a 10" ex POS LCD monitor but it is not bright enough for outside use. Next job: rip it apart and replace the backlighting with bright white LED's! (More current to find!).

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Old 14-12-2008, 13:45   #3
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About 2 years ago a friend and I rounded up a few notebooks, all HP ones, one a home type multimedia and the others all mid range business machines (top end machines will draw more). We got approx 2 amps for all of them running a nav program once the batteries were charged. The ECS I use is writing continuously to the hard drive (like all the time as it logs every NMEA sentence it receives from all sensors) and draw was 2 amps approx (in fact a little under). One cannot go by the rating on the external power supply as it includes for charging, efficiency loss and fudge factor.

The impression I get is often when people quote current draw for the machines they include battery charging - which is wrong because even if one does charge the battery using the boat's supply and that draw is, say, 4 amps it is not lost energy except for the small conversion loss in transferring the energy from boat's battery as storage to the notebook's battery as storage.

Notebooks I and friends have tried that have cell configuration in their batteries that are around 12v (actually comes to around 11.4-11.8v for Li-Ion and is found written on the battery pack - these are normally, but not always, 6 cell packs with 2 banks of 3 cells in parallel) which covers most except the high end machines have run fine on just 12v from the boat's supply straight into the machine. I would not do this though unless one has a good quality DC supply on the boat with spike protection. Obviously the notebook's battery won't charge so I take it out - that may be a problem if powered off the same batteries as used from engine cranking as the notebook probably will die on the volt drop when cranking, but I haven't (and wouldn't) tested that. Of course, charging voltages will not worry the machine as most have 18+ volts stuck into the back of them if on their own power supplies.

Some few notebooks "swap notes" with their AC power supply and won't run off another supply without some jiggerypokery (I am told this is mainly Dells but I can only comment that it is unusual and I have never had the problem arise myself with HP - just something to watch for).

I carry a DC buck converter power supply to give me the charge volts (ie the 18 or whatever volts) for the notebook so as I can charge its battery without using the inverter, and carry the notebook's AC power supply just in case the buck converter fails (as they can ). A point worth noting is people often claim the buck converters are more efficient than using an inverter because they think there is only one conversion step in them ie 12v to the 18+ volts. In fact they work by taking the 12v converting that to AC then that back to the higher voltage DC, so same number of steps and in similar way as if one used an inverter and the notebooks AC power supply. There are efficiencies due to size though ie not running a 2kVA inverter to run a little 80 watt load. The buck converters being switch mode type boxes can be noisy (winding cables on ferrites usually needed if using SSB) so running the computer direct off the boat's 12v supply avoids that.

I personally like HP as have had no problem with them but mainly because of the the very comprehensive backup they give on their web site and via email alerts if one registers for them - email alerts for all software upgrades and for hardware/operational issues found arising in service together with their warranty status or work around, technical manuals detailing complete dis-assembly of the machine and component details right down to each screw type, etc. I have been a consultant for many years and HP business machines are what I see most with others doing similar - it may be that the level of support is not so comprehensive for non business machines but I have never checked on that. Of course, some other manufacturers may do the same but I have never checked - but something to keep in mind in my opinion.
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Old 14-12-2008, 14:03   #4
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The new Intel Atom based "Netbooks" are available from most major notebook manufacturers now. They all use the 1.6Ghz N270 processor and the GM945 chipset from Intel.

Power consumption is around 10 watts although I haven't put a meter on mine. Most use a 36 watt AC/DC power brick. The input voltage varies with manufacturer. I have an Asus eee Pc with the 10 inch screen. It uses 12 volts and has a 6 cell, 7.4 volt battery pack. The MSI Wind uses a 19 volt input.

The Intel Atom based laptops are priced well, have good computing power, low power consumption and are very portable.

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Old 14-12-2008, 15:55   #5
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Phiggins has successfully converted an OLPC XO computer. This thread is long but discusses all the salient points, including your question:

Quote:
While it was charging the XO battery it drew about 2.5Amps but after it was fully charged it was only drawing .6A when the I was on the lowest brightness setting for the screen and .8A on the highest.
I think that was before he wired it in directly. How is that for low power?

Oh, and they're running the buy one get one program again.

Note, this is not for the technologically faint of heart.
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Old 14-12-2008, 16:20   #6
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Mmmm, if one is happy with all or most of small screen, little keyboard, no optical drives, no hard drive, etc in pursuit of low current then a PDA is surely the way to go .
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Old 14-12-2008, 21:13   #7
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I used an EeePc this summer on the Hawaii race/return. I wouldn't attempt major video editing on it, but it ran Expedition, Winlink/Viewfax, my custom nav monitoring/logging/AIS program, Excel, and probably more that I forget, and it did just fine.

I stuck a USB hub on it for an external keyboard, a trackball, and an RS-232 to USB mux. The EeePc drew about 2A. You need good eyes or glasses for the small screen, though, and the external keyboard was much appreciated. I ran the thing 24/7. I had two -- one as a backup, and these were manufacturer-loaded with WinXP. I didn't notice any RF interference on VHF or SSB, but I didn't do a full survey.
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Old 14-12-2008, 22:32   #8
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In search of Low power performance

You have already gotten the advice to throw away the inverter and do direct DC to DC. So now on to the PC. The biggest power hogs are the display, the drive and then the processor and RAM. There are several new machines out that use solid state drives. Look for these to come down in price next year. The solid state drives use significantly less power. The newest generation (smallest geometry) mobile processors will reduce power, but you will add it back with RAM for the applications you want to run. With the display you are stuck. To have any chance of daylight readability, they use power. There is new tech coming, but not soon. Check out Dell's site. They at least have some cool machines to look at. IMHO, Sony Vaio and IBM are probably still the best in class machines.
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Old 15-12-2008, 02:14   #9
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Quote:
Originally Posted by MidLandOne View Post
Mmmm, if one is happy with all or most of small screen, little keyboard, no optical drives, no hard drive, etc in pursuit of low current then a PDA is surely the way to go .
Well, you bring up some good points.

I would argue the reason why so many laptops use a lot of power is due to the larger screens, the optical drives and the spinning hard drives. The XO is remarkable flexible, but the number of program is limited by the sized of the SD card out there. 32 GB is the largest I've found out there but that is more than enough for a lot of things, except tons music and video, for wich you could use a thumbdrive. The machine has a very sharp screen and a sharp, low-power display with a b&w even lower power daylight-readable transreflective mode.

In terms of functionality per dollar and amps per functionality, it fits the bill. However, it certainly isn't perfect. I don't like the keyboard for reasons you noted. Then again, it's for children or hobbyist adults so it's just some you put up with or attach a keyboard (and mouse, the trackpad is not so hot either) to.
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Old 15-12-2008, 06:31   #10
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Check out ARTiGO DIY computers. I saw one on a dockmates boat in La Paz. 12 volt Neat system. This guy had a wireless keyboard and remote flatpanel set up with his. Small powerful energy efficient unit that was hard fastened in place. Very flexible system for small bucks. This guy bought XP for it, and isn't bothered with all the preloaded crap.

I bought an Asus. Not so thrilled with it. Too much bloatware and it locks up all too often. The ARTiGO looks like a great system. You simply buy what you want, instead of buying debris you don't need.
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Old 15-12-2008, 07:03   #11
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Check out ARTiGO DIY computers. I saw one on a dockmates boat in La Paz. 12 volt Neat system. This guy had a wireless keyboard and remote flatpanel set up with his. Small powerful energy efficient unit that was hard fastened in place. Very flexible system for small bucks. This guy bought XP for it, and isn't bothered with all the preloaded crap.
Thanks for the link. It provides an interesting alternative. The specs suggest, however, that the power consumption would be moderately higher than a laptop.

"At idle, the Artigo we built, which includes 1GB of RAM and a 7200RPM hard drive, consumes just 12W at idle and 8W when in standby mode. We ran portions of PCMark05 just to check power consumption. At full bore, the Artigo was pulling a mere 23W. Again, that's system consumption, with the hard drive spinning, the VGA core pumping out pixels, and the network port live"

Some people have raised the possibility of connecting a laptop via a dummy batery directly to 12v. (not via a 12v plugpack as I do). Has anyone done this? I would be interested in details.
Thanks John
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Old 15-12-2008, 21:00   #12
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If you go to Tom's Hardware site http://www.tomshardware.com, they have quite a few articles about the actual power draw a computer has (both laptop and desktop). The Atom, which is a low power CPU, is saddled with an older chipset that sucks down the power. Lowest power at idle is about 20 W.

Here's an article that will be interesting:
Atom, Athlon, or Nano? Energy-Savers Compared : Which Is The Best Low-Power Platform? - Review Tom's Hardware
Efficiency: Core 2 Nukes Atom On The Desktop : Atom Just Isn’t For Desktops - Review Tom's Hardware


The Atom also seems pretty underpowered for some stuff that I need a computer to do, such as photograph editing/RAW conversion and running Autocad & Rhino.

So I plan to build a Core 2 Duo box, with a mobile desktop motherboard. The Core 2 chip draws more power, but at idle it's pretty similar to the Atom and it's "performance/watts" is quite a bit higher than the Atom on CPU intensive tasks. I figure most cruisers would be ok with an Atom however. I will use laptop drives and an 15" LCD that runs on 12V. The total package will run about 4A (1A for display, 3A average for computer).
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Old 15-12-2008, 21:14   #13
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Some people have raised the possibility of connecting a laptop via a dummy batery directly to 12v. (not via a 12v plugpack as I do). Has anyone done this? I would be interested in details.
If you read my post above you will find that I go into some detail about this. Have never heard of a "dummy battery" and never heard of anyone needing one if connecting to the boat's 12v supply.

You know what RTFM means no doubt? I now introduce to you RTFT(hread) .
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Old 16-12-2008, 00:00   #14
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First of all, whether a low power laptop runs directly off 12V DC, as required by the original poster, is an issue of secondary importance since efficient DC/DC converters, such as the Trust PW1150p, which can be bought for US $40-50 and produces output voltages between 14-24 V, will work with most laptops.

Secondly, my Sony Vaio VGN-UX280p with 1.2 Ghz Core Solo cpu, 1 GB core memory, 30 GB hard drive and Windows XP professional, runs pretty much any software I might want to use as a cruising sailor while typically consuming less than 12 W (if not charging). As the Vaio UX series goes, the 280 is a low-end system. The newer UX systems with Core 2 Solo cpu and solid state drives should use about the same amount of power (sine the higher consumption of the duo processor should be largely offset by the lower consumption of the drive), while offering substantially higher performance,,,,,, at a price, of course.

The Vaio UX is not for everyone, alas. Because of it's 4.5" 1024x600 WSVGA screen. it helps when one is a bit myopic. I can manage to read the screen directly in a pinch, e.g. when linking in to airport networks, but for serious word processing -- let alone audiovisual editing chores -- I connect to a 12V, 8.4" Xenarc SVGA LCD screen (available from KarPC) that also draws approx. 12 W, thus ending up with about 24W total. Some users like to switch to its alphanumeric touch-screen mode (i.e. using a small stylus to select letters and numbers on the screen, PDA-style) but that does not appeal to me.

This is not an inexpensive solution, the low-end Vaio UX systems are occasionally for sale around US $ 1,000 and an 8.4" SVGA Xenarc screen can sometimes be found for around US $ 200. The high-end Vaio UX systems with Intel Core 2 Solo processors and/or solid state drives will be hard to find under US $ 1,500 or so. On the other hand, this season I have been using a Patriot 32 GB flash drive to effectively double my HD capacity at a cost of only US $150.

When it comes to traveling with a computer, however, the Vaio UX is hard to beat. A little bigger than my fist and only weighing 1.2 lbs, it also is very easy to protect on board or underway. e.g. by using a small, sturdy Ziploc bag. Because of it's built-in triple wireless capability (WiFi, Bluetooth and GPRS) one can connect in many hotspots (e.g. to make Skype calls) and it's built in double (forward and backward-looking) webcam allows fast copying of documents.

Have fun!

Flying Dutchman
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Old 16-12-2008, 04:24   #15
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Quote:
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If you read my post above you will find that I go into some detail about this. Have never heard of a "dummy battery" and never heard of anyone needing one if connecting to the boat's 12v supply.
.
Yes I did read your original post and enjoyed it. I donít think I understood it correctly. I assumed when you said:
Quote:
Originally Posted by MidLandOne View Post
battery as storage.
Notebooks I and friends have tried that have cell configuration in their batteries that are around 12v (actually comes to around 11.4-11.8v for Li-Ion and is found written on the battery pack - these are normally, but not always, 6 cell packs with 2 banks of 3 cells in parallel) which covers most except the high end machines have run fine on just 12v from the boat's supply straight into the machine.
that you were feeding the 12v direct into computer using the sockets that normally input power from the battery. Hence the need for a dummy battery. This would seem to be a great idea and would be the most efficient way of driving a laptop. It eliminates the computer trying to power up any circuitry that would be used to charge the battery. It would also be easy to feed the computer exactly what it wants via this input which is as you point out 11.4-11.8v (some simple circuitry to filter the boats power supply should nicely drop the voltage to this level).

I presume as you didnít understand the reference to the dummy battery you actually mean feeding the 12v via the normal power in socket. It is interesting, and useful to know this works. I would be a little concerned that feeding 12V into an input designed for (16 to 18v or as in my case 20V) would lead to some long term reliability problems due to some of the components carrying 1.5 times the current, but if I now understand your post correctly you have found this reliable.
Sorry for misinterpreting your post. In my defense I used to write exam questions for university students, despite a committee of several academics considering the question it was amazing that sometime a large percentage of the students could misinterpret the question in ways we had never considered and they had a serious incentive to RTFM (or RTFQ). Generally upon rereading the question it was seen that the studentís interpretation was not what was intended, but indeed valid.

It also means if I can claim the dummy battery idea as original, but I will have to try it on my own.

On a separate issue I understand you donít feel A DC to DC converter to be more efficient than an AC to DC converter run from a small inverter. With both my computer and my wifeís computer this is not the case in practice. We save about 25% running the DC to DC converter. My inverter is not large at 600W.
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