Laptop Computers: Most Energy Efficient?

paulstamser · October 2010

Hi,

I'm in the market for an energy efficient laptop computer for use in a 12-volt, off-grid PV/battery system.

Any suggestions?

I don't need the biggest or most powerful computer. On the contrary my internet and other computer needs are modest. I need a 14-inch screen but no larger. Most important is low energy consumption and ability to run off a 12-volt PV/battery system.

Right now I'm still using a c1998 Mac PowerBook G3 Series that only uses about 20-36 watts depending if I'm using the internet or not. But that machine is obsolete and it's harder to access the internet with it. I am considering buying a Windows machine (for the first time) and not just a Mac.

Any suggestions? If so, please tell us the make and model and how much power the computer uses in watts. Both while connected to the internet and not connected. The modem and internet connection does take up additional power.

This subject should be of interest to all off-grid and other PV system users as the most energy efficient equipment is always desireable.

Thanks!

BB. · October 2010

Re: Laptop Computers: Most Energy Efficient?

I just got a Motorola Droid X., Includes 5GB of Internet for $30 per month plus $200 up front. --- Hmm, wonder if you find a keyboard and some decent application software (kind of like Open Office, FireFox, and such)...

For Internet access--The Android OS + something like PDANet will work tethered to a Mac or PC (I think you can make it work for Linux too). No tethering charges from Verizon (does not make them happy). $30 per month for "unlimited" Internet (unlimited appears to be 5 GBytes per month in the fine print). At this point, Verizon has no control over Android OS tethering (cannot "break" PDANet at this time). Does not support WifFi tethering (you either need to pay Verizon more money or possibly hack the phone--Root Password is already known and I think people have done that).

Tethering is not bad... Computer powers the phone, and you may get around 1Mbps download and 250kbs upload. Supposed to "be better" in the next year with network upgrades. T Mobile is already showing upwards of 7mbs (if you have GSM service in your area).

I have only tested PDANet a little bit (freeware version---after several weeks turns off https: service until you purchase a password for $20 or so one time purchase per Android phone.

Otherwise, I am using a netbook with a 10 inch screen and around 20 watts. It is an HP (was not very expensive)--But given where HP is right now with quality--I would not recommend it.

Lately, from what I hear, Toshiba Computers are reliable... I also like the Lenovo (aka IBM Think Pad series--but I have only had that one for 6-8 months so far).

I can throw a Kill-a-Watt meter on the Lenovo and crank it down to minimum power and let you know what it reads (if you are interested in a PC type machine).

-Bill

mikeo · October 2010

Re: Laptop Computers: Most Energy Efficient?

I'm in the market for an energy efficient laptop computer for use in a 12-volt, off-grid PV/battery system.

If you don't actually require a laptop, I have a FIT PC Slim that runs linux and draws less the 5 watts and runs off 12 volts DC. They have the more powerfuls FIT PC2 that draws 8 watts. Add a USB keyboard, USB mouse and a standard 14 inch LCD monitor of which most runs off 12 volts DC and you have a system that draws less then 25 watts, works off 12 volts with no adapters and is quite versatile. This is a full pc system with audio, built in WIFI and 160GB of disk.

n3qik · October 2010

Re: Laptop Computers: Most Energy Efficient?

If a laptop is not needed, look at this:

http://us.shuttle.com/barebone/Models/X50V2_spec.html

It is a bare bones, so you will need a 2.5" hard drive, ram and an OS.

I have one. Using it as my home automation PC. It is fanless + SSD = very quite.
Draws about 20-30 watts.

dwh · October 2010

Re: Laptop Computers: Most Energy Efficient?

I'm using an Acer Aspire One ZA3 / 751h.
2g ram, 250g hard drive, 11.6" screen, full-size keyboard.
Dual boot Win7 / Linux.

I chose this one for the full-size kb and the Intel Atom N570 cpu which uses less power (and is a bit less powerful) than the N270/N280 cpu used in most netbooks.

In Linux acpi reports 9w-13w running - depending on cpu throttle 800mhz-1300mhz - and 14w when charging.

I added a 9-cell 7200mah battery, and a decent quality 12v charger (90w rated - does not get hot).

I get 8 hours or more when using it for watching vids or word processing or surfing the net with the internal Atheros wifi card.

I get about 6 hours when using my hi-power Alfa wifi card cranked up to its full 1w output power.

paulstamser · October 2010

Re: Laptop Computers: Most Energy Efficient?

Wow, great responses! Thanks.

I've been assuming that laptops are more energy efficient over other type computers, but after reading some of these posts maybe not. I'll have to read them more closely.

But I do like the laptop because I do sit in my Lazy Boy with it on my lap and it's very comfortable that way. Not hunched over a desk. Right now I'm looking to get another old used Mac like the ones I've been using. But that's just a stopgap solution as they become ever more obsolete.

I am considering going over to a Windows machine if I buy new. And I did look at a couple of netbooks in the store but they didn't seem very energy efficient. Price was right tho. I wrote down the specs from them. I'll dig that info out.

BB. · October 2010

Re: Laptop Computers: Most Energy Efficient?

You pretty much need to bring a kill-a-watt meter and measure the loads in your configuration/usage...

The old desktop computers were real energy hogs... The newer ones are being designed with much of the power savings stuff that is in laptops today.

The screens are a significant use of power... How efficient they are, how much back-light you use, your room lighting, screen time vs background processing, etc. all make can make a 30% or more difference in power usage.

One suggestion--Compare the "matte" screen vs "glossy" screen computers in your situation.

Glossy is popular right now because they look real pretty in a dark room and are cheaper to make. A matte finish screen looks a bit fuzzier because of the matte finish--so the underlying screen has to be better for "equal" visual appeal... But compare the difference between the two when you have lights/light background behind you. The glossy screens are a pretty good mirror of the background behind you.

Pretty much all home class machines are glossy, and all business machines are matte finish. I have pretty much limited myself to matte screens these days.

-Bill

solar_dave · October 2010

Re: Laptop Computers: Most Energy Efficient?

I used a kill-a-watt on my MAC-mini and it showed 18-23 watts , no screen. Pretty efficient for a core2 host with 4 gig of ram and 320 gig drive.

Cariboocoot · October 2010

Re: Laptop Computers: Most Energy Efficient?

My wife's Gateway NV58: 32 Watts at start-up. The desktop unit it replaced: 190 Watts (drives running). I'd say that's a significant difference!

My Acer AspireOne ZG5 (the original version Linux Netbook): 12 Watts.
Mind you it can't do much other than surf the 'Net and a bit of OpenOffice document handling. :roll:

Those numbers just measured with a Kill-A-Watt clone: UPM EM100 (slightly quicker than the K-A-W - sometimes picks up start surges).

RCinFLA · October 2010

Re: Laptop Computers: Most Energy Efficient?

Take a look at the Atom motherboards if you don't need super speed.

You can get one with single DC input that draws about 15 watts. If you want to keep power low, use a solid state hard drive with it.

Don't forget monitor. Best LCD's are 15-20 watts in 19"-20" side. Set your OS to shut down monitor in 5 minutes (or less) of inactivity. Backlight level is 2/3's of consumption. Back it down a bit.

n3qik · October 2010

Re: Laptop Computers: Most Energy Efficient?

Also, some LCD monitors are now LED back lite, most if not all notebooks are now LED back lite. With an LED back lite display, you can turn it off/on in a shorter time span and not shorten it's life. Do that to an older CCFL display, it will not last.

paulstamser · October 2010

Re: Laptop Computers: Most Energy Efficient?

On eBay I scored a couple of used Mac Powerbooks like the ones I'm using now dirt cheap. Hopefully I can get something running properly using cannabalized parts and limp along for a time yet before getting something new. I like to have at least 3 working computers. An internet job. A work (writing) job. And a backup job. Don't ask how many chainsaws and vehicles I own. Still interested in your systems, however, as these old Macs won't last forever.

paulstamser · October 2010

Re: Laptop Computers: Most Energy Efficient?

One website says this about netbooks:

"Many manufacturers are now using solid-state drives (SSD drives) instead of hard disk drives as their storage system, but SSDs are still relatively limited by expense and capacity in comparison. Intel Atom, AMD NEO CPUs are all used as low-power, higher efficiency processors for the ultraportables."

That sounds goods in theory, but their idea of "low-power, higher efficiency" and mine might be vastly different. The netbooks I looked at in the store used some 47.5 watts (10-inch) and 65 watts (13-inch) each.

Of course that wasn't measured power consumption but what it said on the label. I wonder what the actual difference would be between measured power use and what the label says? Any rule of thumb about that?

BB. · October 2010

Re: Laptop Computers: Most Energy Efficient?

To be "flip"... The proper rule of thumb is to use a Kill-a-Watt or equivalent meter to measure charging and steady state power...

My guess is that, once the battery is charged, the computer will use about 1/2 rated capacity of the power brick... During charging, probably closer to rated capacity.

-Bill

n3qik · October 2010

Re: Laptop Computers: Most Energy Efficient?

That is the max power of the power supply. It is rated at the level to charge a dead battery and run the netbook at full power. I have a 10" Atom netbook and I think with a fully charged battery, it idled at 10-15 watts.

paulstamser · October 2010

Re: Laptop Computers: Most Energy Efficient?

Thanks for the info.

Since it's not practical to put on a meter on every computer I'll use the 1/2 power rating of what the label says. That means the netbooks I looked at would use about 24 and 32 watts plus what the DSL modem uses.

My old Mac laptop with 12" screen connected to a DSL modem plugged into a small inverter together use about 31 watts. My 14" job probably uses a little more. With the modem turned off the 12" Mac laptop alone uses about 19 watts. Energywise it's very competitive with the latest netbooks.

BB. · October 2010

Re: Laptop Computers: Most Energy Efficient?

Since the power levels are very dependent on back light settings and what programs are running on the computer--My guess is that your estimate of 24-32 watts may end up being 2x what a "typical" user who does some typing/email/web browsing would see "on average".

The 24-32 watts may represent a 100% screen back-lighting and lots of processing going on (from my small sample size of a netbook and a couple laptops).

Not that over estimating power usage by a factor of 2 is a bad thing to give you some cushion...

-Bill

benthere · October 2010

Re: Laptop Computers: Most Energy Efficient?

My 5-year-old MacBook uses 13-Watts once the battery is charged - using wireless but not processing much while browsing the web or reading/sending email.

A nice thing about a laptop is the ability to load shift. I try to plug it in after the battery bank makes absorb, then unplug it at night after the sun goes down. 13-Watts isn't much, my wife and I each use one almost constantly.

MisterB · October 2010

Re: Laptop Computers: Most Energy Efficient?

Here's a real simple way to look for a energy efficient laptop: Just look at the specs for how long it will run on it's internal battery. If you can run it 5-6 hours on it's own battery, it was designed for low power consumption. I'm using a Thinkpad with a Pentium Mobile proccessor and it draws less than 24 watts under a moderate processor load like web browsing.The more work the cpu does, the more power is consumed. My Thinkpad will draw 36 watts at 100% cpu use which will only happen if I'm using cpu intensive software like 3d rendering software or converting video from one format to another. Desktop replacement laptops tend to be power hogs and I have a Sony Vaio in that catagory with a Pentium 4 processor that I just use for home entertainment and it came with a 90 watt power supply and can easily consume 60 watts and the full 90 if I'm using it and it's charging the battery at the same time. And the battery use rating for it is just under 2 hours with a good battery.

notsobright · October 2010

Re: Laptop Computers: Most Energy Efficient?

not sure if has allready been mentioned but another way to minimize some of the current drain by eliminating the internal hard disc and booting from a flashdrive even though some systems dont support booting USB Ive found it is still possible with PLOP software

kinda of topic mabey but this sort of fits in enough not to warrant a new topic:

is anyone aware of a netbook or laptop that will run directly off 12vdc?

I have an old toshiba that does OK but it was designed to use 15vdc so when my system gets down below 12.6 volts the toshiba switches to its internal battery.

Id like to find something that will run stable directly from my 12vdc system without the need to use its own internal battery.

thanks

bryanl · October 2010

Re: Laptop Computers: Most Energy Efficient?

The first consideration is whether you need the portability of an all in one laptop format or not. If you do, and your primary use is I'net access, then a netbook (or one of the very fancy cell phones) is probably the most energy efficient.

If portability isn't a big issue, the options open up. There are some (as mentioned above) computers that run linux and use very little power, there are the Atom based, standard PC compatible, low power computers like the Asus EEE line, and you can find other slim desktop styles that are very low power. Look for CULV (consumer, ultra low voltage) as a qualifying acronym.

The display options are getting more interesting. I use a Vizio 23" LED backlit Energy Star rated TV with an Asus EEE PC. Together they use about 35 watts (Kill A Watt measured) showing an HD movie from an external USB powered drive. Both will run off an RV's 12v battery directly and should be a bit more efficient without the wall warts but I haven't measured that yet.

dwh · October 2010

Re: Laptop Computers: Most Energy Efficient?

My Acer ZA3 runs off the 12v adapter I bought just fine. Personally, I prefer the adapter since it takes 10-15v on the input and kicks out a nice steady 19v on the output.

Lowering voltage increases amperage, as we all well know. But I see it as a percentage thing. If you drop the voltage and kick up the amperage on a 120v system the few percent difference doesn't hurt anything - but how well do circuit board traces handle the same effect?

dsp3930 · October 2010

Re: Laptop Computers: Most Energy Efficient?

My wife's HP Mini netbook (purple plaid) uses a 12v @ 3A adaptor.
It consumes 10-15 watts while in use per my Kill-A-Watt depending on usage and just over 8 watts with the lcd off/shut.

Lefty Wright · November 2010

Re: Laptop Computers: Most Energy Efficient?

Switching from a Mac to a PC makes me think that the extra time you spend trying to get Windows 7 to do anything may negate the energy savings.

Is it just me or is windows 7 the worst os ever?

MisterB · November 2010

Re: Laptop Computers: Most Energy Efficient?

My general experience with laptops is that I get around a 30% improvement in energy efficiency when I use a 12v DC adapter instead using and AC adapter off the inverter.

I just shake my head at those who insist on using power hungry desktops in an off the grid situation.

To measure current, I use an AC/DC clamp meter rated at up to 200 amps. I can easily measure charge and load on both the AC and DC sides of the system.

n3qik · November 2010

Re: Laptop Computers: Most Energy Efficient?

Lefty Wright wrote: »

Switching from a Mac to a PC makes me think that the extra time you spend trying to get Windows 7 to do anything may negate the energy savings.

Is it just me or is windows 7 the worst os ever?

With a MAC at home and Win XP & 7 at work.

I would rate best-worst:Mac-XP-Win7, Tried Vista in our lab. It was so bad, We did not install it on any of our production machines.

I am using at home an 24" LED Cinema Display with a 13" MAC Book Pro laptop. This setup gives me both desktop performance with the portability and energy usage of a laptop.

OT: I just added a new home server. It is a HP Microserver:

http://h10010.www1.hp.com/wwpc/us/en/sm/WF05a/15351-15351-4237916-4237918-4237917-4248009.html?jumpid=re_R295_prodexp/busproducts/computing-server/proliant-microserver&psn=servers

It is running VMware ESXi 4.1 with 2 virtual machines @ about 40 watts.

notsobright · November 2010

Re: Laptop Computers: Most Energy Efficient?

notsobright wrote: »

is anyone aware of a netbook or laptop that will run directly off 12vdc?

to be more specific, directly off 12vdc without and adaptor. straight off the battery into the computer. anyone know where to find out what systems this is possible on?

lots of good info on this thread!

thanks

dwh · November 2010

Re: Laptop Computers: Most Energy Efficient?

I run Back|Track 4.1 Linux and Win7 dual-boot on my netbook. The main issue is the little GMA500 vidcard. With all of the default Win7 video enhancements turned on, it dogs out, but turn all that off and it works fine.

Same with services - I have always (since NT beta) disabled any services that I can. Every new release of Windows seems to double the number of services running in the background. Kill off as many as possible and it makes a noticeable difference.

I haven't had any real problems with Win7 except that Civ4 had font corruption and also would only run an hour or two before crashing. Compatibility settings didn't help (which really blows, since I've been a Civ-a-holic since it first came out). I'm pretty sure though that that is directly related to the vidcard and not Win7.

I've got a 2g SD stuck in the side of my netbook for ReadyBoost, but I haven't decided yet if it actually makes any difference. Maybe not as my netbook has 2g of ram and a pretty fast 250g drive.

I like Macs - always have (I used to love my hot-rodded SE/30 with Daystar 68040+math co-pro and 64 meg ram). I'll work on them if someone pays me. But I doubt I'll ever buy another. Apple's Jobsian control freakery has always been irritating - nowadays it's just gone too far. I simply am not going to pay someone to tell me what I can and can't do.

I should also note that I wasn't all that happy the first time someone handed me an OSX box that they had lost the password to. I couldn't believe how ridiculously easy it was to hack it and reset the password.

n3qik · November 2010

Re: Laptop Computers: Most Energy Efficient?

notsobright wrote: »

to be more specific, directly off 12vdc without and adaptor. straight off the battery into the computer. anyone know where to find out what systems this is possible on?

I ran my EEE PC 9" directly off a battery. This unit could take up to 13.5 volts.

Laptop Computers: Most Energy Efficient?

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