Best laptop for rv life

[Totem]

One of the great features about these type of forums is a vast amount of information can be exchanged.

On this particulate forum, I've observed a wide range of participants, from absolute new person who knows nothing about a subject, all the way up to and including people who have years of training, information, and experience. I've also observed that if someone posts inaccurate or incomplete information, Its usually corrected or expanded upon in friendly manner.

As I read thru posts, one of the things that I bear in mind, I'm not the only audience or consumer of any particular post or thread, and regardless if something may appear to be "psycho babble" to me, I'd be willing to bet, someone reading the post(s) appreciates the information.

John Mc

88 Dolphin 4 Auto

well said and I agree. we are all friends here; i admit i am guilty of devils advocacy - with a purpose- not just for the heck of it.

didactic logic can at times be tempting to simply prove something can be done or exists; I however prefer to use it to an end; like getting something to work cheaply. I also like to do things right though so i will spend money where it counts (shocks, axles etc.) :-)

[Derek up North]

... if something may appear to be "psycho babble" to me, ...

Or sometimes a psycho babbling?

[Totem]

Totem, You and Stamar are correct. Given the age of the technology in our Toyhouses (1980), Its very easy to find ways to reduce power consumption if you just want to stretch the time or increase the load of the power we consume.

LEDs is a perfect example, they will consume 1/5 the power for the same color and brightness as an incandescent bulb. That means I can run it 5 times longer, OR I can run 5 more lights.

The little Inverter Stamar referenced. I don't want to bore people with babble, but I would recommend checking to make sure it regulates before hooking up a computer. If you have a voltmeter, read the output voltage while the inverter is supplied with low battery input voltage (say 12.0 volts) then start the truck (Input should now read around 14.0 volts) as see if the output voltage changes. Its probably OK, but worth checking so you don't fry an $800 laptop.

ALSO - I noticed the inverter uses a switching frequency of 380khz. When you get it up and running, see if this is interfering with your radio or TV.

Stamar - If you or your Electrical Engineer friend buy one of these inverters and hook it up, give us a report on what you found and how its performing. This looks like it could be a good candidate for other projects that need something other than 12 Vdc. (i.e LCD TV)

John Mc

88 Dolphin 4 Auto

in my case; I'd like more juice to be going to my batteries and inverter during night travel so my kids can watch movies with the small 400 watt inverter not being stressed by the fridge being on. In my rig the fridge is the battery/alternator/inverter killer. I get around it by running propane (which sometimes goes out then it switches to 12 volt and kills everything) or i just turn it off. i had toy'd also with the idea of that 180 am alternator connected to single 12 volt house battery then powering a huge inverter run the rooftop AC during july daytime travel but decided its too dangerous or would fry the inverter.

[stamar]

I'm not buying anything to experiment with it I'm not like that ill be positive it works.

No offense I did try to drop it so it didn't embarrass anyone but someone came out with a preposterous theory that I knew was wrong, I have evidence I've seen with my own eyes and it makes no sense anyway

Then two or three people ran with it as if it were correct, they have heard it, so I ignore the subject maybe doubting my brain.

Totally ignoring that channel of research based on something that's actually ridiculous. No offense but it makes no sense.

The rest of the thread is great I just want to say none of that. There's chiming in with what you know and then there's bsing and that is not friendly.

[stamar]

my project is running a laptop on dc with 12 volts and there was helpful advice about eliminating the inverter and power supply.

I have seen it done with my own eyes with parts you buy at a stereo installer shop. Not ordered but bought off the shelf they are so common.

It is just academic for most part.

What's weird is someone says something that's so wrong it takes no education at all.

Like here's 0 volts, and my 12 volt battery made it 12 volts. Is that impossible? No its not so that's crazy bs. But people are condititioned to doubt their own mind if someone sounds convincing.

Anyhow enough on that I jsut don't want to be telling someone to shut up so I'm doing it preemptivelyy.

[stamar]

in my case; I'd like more juice to be going to my batteries and inverter during night travel so my kids can watch movies with the small 400 watt inverter not being stressed by the fridge being on. In my rig the fridge is the battery/alternator/inverter killer. I get around it by running propane (which sometimes goes out then it switches to 12 volt and kills everything) or i just turn it off. i had toy'd also with the idea of that 180 am alternator connected to single 12 volt house battery then powering a huge inverter run the rooftop AC during july daytime travel but decided its too dangerous or would fry the inverter.

Oh ya I had that figured out with my last toyhome that had the useless roof air. Some sort of blood contract between toyota and honda.

The roof air doesn't need more power than the generator makes, it needs more watts. So its cheaper to charge the batteries and buy a bigger inverter.

But I don't have useless roof air on mine now so I'm not worried about it and I'm not buying one

I have the whole project written down from harbor frieght using the 800 watt generator and a 3000 watt inverter.

[Derek up North]

Anyhow enough on that I jsut don't want to be telling someone to shut up so I'm doing it preemptivelyy.

Me neither.

[waiter]

Sorry Derek, But as I was typing that, I had a vision of Red-Green and your avitar/ ( I love Red Green, )

I like experimenting, especially if it doesn't cost to much. That little power supply could answer some problems of getting wierd voltages to appliances that we'rn't really ment to be in a Toyhouse, laptops, TVs, just about anything that uses one of those "WallWart" power supplies (the little plug in transformers)

If someone gets one, keep us informed.

JOhn Mc

88 Dolphin 4 Auto

[Totem]

It was like 99 degrees all Sumer plus index, so I will be trying to find a way to get mine running while driving next year. I'm leaning towards a small diesel genset from Cali I think to run the AC.

Excited to begin me TEG generator project soon too. All parts are en route. The ammo box stove should be kicking 40-50 watts I hope

[bajadulce]

We have a couple of older laptops laying around, and might try hooking one up to 12v direct even tho the AC/DC adapter reads 18v output. My hunch is that this voltage is not the actual voltage required to run the laptop but rather to charge the laptop's battery? Of course will remove the laptop battery. Just an experiment for fun. Will edit post/report back.

Edit:

Just looked at the laptop's battery. Sticker reads 11.1V @ 48W/H. So would suspect that if supplying 12+VDC to the adapter jack won't run the machine, bybassing the jack via the laptop's battery terminals should. Tho there are several battery terminals on the "pack" which would indicate different voltages and signals being sent to the mobo... to be continued.

* Dissassembled the laptop's battery pack: Looks like there are 6x ~2v batteries and a fancy controller device.

Edit2:

Appears the AC/DC adapter has more to it than just what's described on the label! There is a 3rd core wire showing about 10v? The outter/inner shields are the + and - 19v

Edit3:

Well crap doesn't seem to want to fire up via the single feed. I tried with the 2 negative wires (11v and 18v negative feeds) hooked up as well but without luck. So must be more going on via the jack than the simple run/charge power lol. Will have to do a little more researching. Oh well gave it a try. Prob would have to hook up directly to the battery pack as noted earlier w/ several different feeds/voltage drops etc.

Way way back in the early computing/offgrid days, there was a small circuit board available that would replace the standard AC/DC power box inside typical desktops w/ a 12vdc input. You simply plugged this into your motherboard with the standard male plug and it did all the necessary reducing to 6v, 3v and 12v, etc. This was real popular w/ the mini-itx platforms and I built one myself (came as part of a case actually). So something like this could be fabricated to bypass the internal laptop battery as well (i.e. replace the 12v internal laptop battery w/ an external 12v source).

Edit. Here's that mini-itx circuit board was describing above: link here

[stamar]

Ya for what it matters the ppower consumption in laptops has more or less stayed the same for a decade.

So my big game laptop has an equivelent for sale today as new, and it uses a similar power supply.

The gpu screen etc all use roughly the same amount of power they are just better.

But one thing seems to be breaking is that now the graphcis card can be just turned off, and the intel cpu has a graphics card built in,

So gamer models can be toned down to use power like a basic model.

The cpu on the other hand uses the exact same amount of watts like its a standard. My old laptop has a core duo and I believe the new i5 is three generations removed but it uses 35 watts.

The low power cpu will use 17 watts.

Almost ready to pick one up. Ordering a vizio from walmart of all places.

[stamar]

No laptops from costco only have 90 days.

In theory you could return one every 90 days but that is gonna bite you in the end.

I was thiinking of getting one from costco and returning it and might just for a power rundown test. However I have since discovered that the modern laptop has just about as much draw as any laptop made in the last 5 years not much magical about it.

[stamar]

the most important aspects of a modern laptop via the amount of power they use

1. the screen. the lowest power laptop will have a small screen, 12 inch. theres a big big loophole to this, merely set the laptop to turn off its screen. at idle the screen uses nothing.

so if falling asleep and downloading a movie lets say have the laptop turn its screen off in a half hour of no contact.

it doesnt help when you really want to type a paper. but i came to the realization that even though i want 12 hours a day of laptop time, i only need about 3 4 hours a day of screen time.

2. the gpu, in a sense. in older tech laptops like the one i have the gpu uses a lot of power even when not gaming. and on the alternate side, a laptop without a gpu uses none.

more modern laptops have optimus optionally used to turn of the dedicated gpu and use the cpus internal one ( i5 I7) yet the manufacturer doesnt have to enable this.

asus and lenovo choose not to enable optimus in most of their laptops. forcing you to choose one or the other. for their own marketing purposes. this lead me to disregard their laptops.

3. cpu. The modern cpu uses 35 w, which is what it has used for the most part for years. the ultra low cpu uses 17 or half. It operates at a little more than half the speed. so you say, why not get a good cpu, and then set it for half speed? will that use less power? Yes it will. not quite as good as the u series cpu does.... but not that much worse actually. Overall my analysis of the modern intel cpu is that i could get a good one like a i7 quatro core, and then with a common app make it use less power similar to a low power cpu when its on rv power, and still have it be super fast when on ac power somewhere.

4. hard drive. the biggest juice user is a 7200 rpm hd, and the lowest is an internal msata ( not regular sata ) ssd drive like in a mac air or any super light thin laptop. somme laptops are compatible with both.

most laptops that come with a ssd standard charge too much for it.

5. the optical drive uses a lot of power. in the event you were watching a dvd or something. I wouldnt ever do that.

most laptops the optical drive turns off on battery power.

that said i definitely did not go for the lowest power laptop i could at all.

I will not be the guinea pig. Im getting a laptop that uses a lot less than my other one. its pretty impressive. i plan to upgrade it to ssd . it isnt a low power laptop at all but im ggoing to live with it because its awesome.

[Maineah]

A big group 27 deep cycle battery should run a laptop drawing 35 watts close to 10 hours. One 1156 bulb draws about 25 watts two and you have cut your time greater then 60%.

[zero]

Ya for what it matters the ppower consumption in laptops has more or less stayed the same for a decade.

No it hasn't. You've missed a few key points, I think. The AC to DC power-supply most lap-tops is extremely wasteful. It wastes more then HALF the power and just makes heat. You already stated that you use the AC to DC converter plugged into a DC to AC inverter. You are probably wasting 60% of your power (not actually being used by your laptop). Better converters are available and are a huge improvement over the older and/or OEM supplied ones.

Here are specs a typical lap-lop power supply that came with a new HP 6 month ago. 125 watts IN, and 65 watts OUT. Note there are 60 watts being wasted and just making heat. Almost 50% waste!

A cheap $399 lap-top with a 8.5" X 14" display when run on DC and used to the MAX draws around 4 1/2 amps at 18 1/2 volts DC. That's with the DVD burner going and screen resolution set high. That's 83 watts. A 125 amp-hour deep-cycle battery run down to half-charge can run that lap-top for 7 hours. When the computer is used in an "average" way, e.g. reading files, maybe playing a video it uses around 3 amps at 18 1/2 volts (60 watts). About 9 hours run time on the same battery and that's constant use. Hitting the keyboard or watching videos for 9 hours steady!

The problems you mention elude me. I don't see any problem and have none when I run laptops. In the camper and in the woods with NO camper. Just a portable power-pack.

The search for a more efficient lap-top seems a bit silly. Just use a more efficient way to power it.

HP CQ62

Power supply – 195 watts in and 65 watts out.

120 VAC in @ 1.7 amps – 18.5 VDC @ 3.5 amps out

DVD burner - max draw – 5 VDC @ 1.3 amps (6.5 watts)

CPU –dual core is 35 watts max

Display – 14” X 8.2” 4 watts max

Harddrive – 7200 RPM – 5 VDC @ 800 MA (4.8 watts)

Entire computer MAX rated – 18.5 VDC @ 4.7 amps (87 watts).

A 125 AH deep-cycle battery can run a 4.7 amp draw for 13 hours when run down to half-charge.

[stamar]

I actually have the parts for a dc to dc inverter ready to go made from stereo installation parts for autos. The only thing that's stopping it is the real life test or the amount of current. These are made for far greater draw than a laptop actually.

But the only time I saw them being used for a laptop it was a small low power laptop

I don't need to buy anything and as far as I know its not generally. For sale but I need a line on the power end for the laptop I end up getting.

Something very cheap hopefully. The power end with chamgable tips might be nice for both lapptops

What's sold as a dc to dc inverter in the business world or an airplane cigarette adapter from apple is very small. However it normally powers a low power laptop

I will worrry about this later.

The numbers on the draw a laptop has on a deep cycle don't help me so much here's why, even if the laptop draws half the battery in twelve hours, or a quarter of the two I will. have, how do you replace that much juice every single day? By running the engine?

Well I won't drive that much. Some but not that much.

So running your laptop for a weekend works and then you are back home to ac power or a long drive. That data won't help me I want to run a laptop every day without charging the battery every few days.

So I need the laptop to after twelve hours maybe take the deep cycle to 90 percent

I need the draw to be close to that incadescent bulb.

[stamar]

My laptop with the 180 watt power supply runs a battery to about 25 percent in 4 hours. Just using the internet . But I will be getting one that uses much less power. If your theories ever have problems with reality they're probbably wrong.

This particular project has a whole train of interesting improvements but the biggest one is the new laptop I'm getting. I have a line on the standard ultrabook which is like the macbook air essentially a low power ,machine. That's actually the answer to the question. A n 11inch macbook air.

But I'm going with a more standard laptop that won't in the end use more than. Oh......50 percent more power I think

[zero]

My laptop with the 180 watt power supply runs a battery to about 25 percent in 4 hours. Just using the internet . But I will be getting one that uses much less power. If your theories ever have problems with reality they're probbably wrong.

If your power supply is 180 watts it means you can double your run time just by eliminating it since it wastes 50% of your power. That makes a lot more sense to me then worrying about the lap-top efficiency in itself.

In regard to finding a way to recharge without running the engine? No free electricity around that i know of. If you don't run your engine - get some solar panels AND a fuel-driven bulk charger. Seems running the truck engine is the easiest way. Even a small alternator like Toyota uses will charge 30 amps at idle. If your computer downs down a battery in a few hours by using 60 amp-hours . . . it will take your alternator - at idle speed - to recharge the battery around in half the time it took to discharge it. Install a bigger alternator that charges at 50 amps at idle speed - and recharge time is down to nearly 1/4 the time, etc. &c. Many off -grid people who live off of a battery bank and solar panels use a DC bulk charger. That is the fastest and cheapest way to charge with engine fuel. A car alternator hooked to a little 3 horse engine. Does the same job as your Toyota but with a tiny engine.

I should get you in contact with an old hippie girl I know in the Adirondacks. She's my age and over 60 - so maybe not quite a girl anymore. She got mad at the power company around 5 years ago after one too many power outages and surges. She claims they ruined her computer. So she turned off the power (with no plan). Bought an inverter and few batteries. Ran then dead and then hooked jumper cables to her Honda car and let it run for hours to recharge. She got by that way for a long time. Slowly she started adding solar panels. She still lives that way.

[zero]

I actually have the parts for a dc to dc inverter ready to go made from stereo installation parts for autos. The only thing that's stopping it is the real life test or the amount of current.

This discussion is sort of going in circles - but one more time.

When you use your lap-top with your AC power supply plugged into an inverter - you have 50% waste in the power supply and another 10% waste wth the inverter. 60% waste before any power reaches your lap-top.

When you a DC to DC converter like I suggested - you get 5-10% waste and that is all. Big difference between 60% waste and 5-10% waste and none of that is associated with the lap-top itself.

You stated earlier that my idea of using a DC to DC inverter was no better then what you were doing with the AC power supply plugged into an inverter.

That is simply incorrect. No electron theory here - just easily verified fact.

[Maineah]

The power rating on the laptop supply is max power not what it draws. I have tested two different laptops with a watt meter at the 120 volt input they run max 60 watts charging the internal battery and drop back to 20-30 once it's charged while working the hard drive. Granted if you take two devices out of the mix your power consumption will be lower but once again you are stuck with the 19 volt input. A DC to DC converter would be the most efficient but care should be taken to make sure you are supplying what the laptop wants if you really like the laptop. Get a tablet mine runs 11 hours on a charge.

[stamar]

Ya you're hopelessly lost I guess I'm not actually worried about helping you figure it out but when I have it set up ill picture it. Nothing new actually but more difficult to find in a retail sale than it used to be.

I have plans to have both a low power laptop and a solar panel and a low power inverter. Actiallt this whole little thread forum is mostly the projects I too on and tried to document so the next full time rver has less of a project.

I wish I had direct links to just the correct led bulbs to buy like are in my sig and didn't have to look that up. I'm sure ill throw the correct dc to dc hardware to buy when I buy that sometime in feb march. Ill have the laptop running regularly by then.

The order I'm going in is laptop next , a much lower power draw laptop. When I have the actual real life draw amount ill see what's. The best to expand. I've got the full led set up and the solar panel before I even have the laptop.

[stamar]

I'm not sure but ill put a fuse in the line maineah.

I've seen the power port melt from too much juice. The dc to dc power converter was something I had going years ago I'm going to say 10 years even. I believe the average laptop uses less power than they did at that time I know it does but I don't have anything to look up to compare.

I ran my sony vgn something using a dcc to dc inverter and it definitely ran longer utilizing a standard starting battery.I didn't have an rv back then at all it was a project for using free wifi in my car, and it was pretty commonly done by people who had that pursuit.

The dc to ac to dc inverters they sell now are crap nothing to do with this project.

[stamar]

the tablet is a type of computer theyve been trying to sell us for a looong time and its maybe finally taking off, with the addition of the cell phone technology.

So its a computer. It has a very small screen, so number one is taken care of there. A big tabllet is the 10 inch one.

it has a very low power cpu, no gpu only the fanciest cpus use an integrated gpu, so like the nvidia tegra cpu gives it some extra power.

it has very little ram because the os is so small. Ram uses power too not a lot but even my old laptop has 6 gb of ram. using 1 gb or less of ram uses less power too.

Even the heaviest duty tablelt uses a mssd drive similar to a macbook air.

no sort of ssd. So overall it makes the grade. put a large 200 gb mssd in a tablet and its a very useful tool for the rver. I dont discount the tablet I think Ill have one soon especially to help out the laptop which might not be able to have enought on time.

For instance leave a tablet on for 24 hours a day to download stuff, and then transfer stuff to the laptop.

its possible a tablet is the only gadget that actually has a low enough power draw to do what i need it too. In that case I wont even struggle with it then Ill learn to live with way less laptop time like I am not and use the cell phone and tablet as my full time thing. I bet the 7 inch nexus can stay on 24 hours with just the panel and led upgrade i already have.

I could just over gadget it lol. but one at a time.

I run businesses off my laptop and I havent been able to get it done or Ive been spending more than id like gaining ac power for a while now so Im looking forward to getting a little more functional in the rv with a fully functional keyboard laptop.

[stamar]

i cant really have a use for a tablet that doesnt have a msata ability, one like my phone only using the microsd cards. just not big enough to download a movie library for me.

If it were Id just use my phone.

so before id buy anything it needs to have at least msata ssd hard drive cabability. All of the tablets i find like that are actually more expensive than the full function full hd screen llaptop im getting.

If I could get a laptop like the google nexus with a hard drive that would work, but it cant have a hard drive yet. theyre not giving that away cheap yet.

[zero]

The power rating on the laptop supply is max power not what it draws.

Only partially correct. On many older ones - the power draw is excessive all the time regardless of use on the DC laptop end. The Federal government and Energy Star got involved an in effort to force computer sellers to use more efficient power supplies. Some older ones were only 40% efficient. Now many are up to 60% from the last Energy Star bulletin I read. A few even reach 80%. What you stated is only true for power supplys with current regulation.

Same goes for the billions of other little AC to DC power supplies used all over the USA for telephones, TV amplifiers, TV boxes, TVs, etc. The European power supplie have been much more efficient for years. Not so with the cheap ones in the USA.

[zero]

.

The dc to ac to dc inverters they sell now are crap nothing to do with this project.

Most of the DC-to-DC converters sold for lap-tops are 90%-92% efficient. You call that crap? Tell me about the "better" ones you know of that greatly exceed that 90%-92% figure. I think you are dreaming. Cite some real figures from specific devices (I already have). In fact, when something is already 90%-92% efficient there is not an awful lot of room for improvement. Would you spend big dollars to maybe gain 1 or 2%? There is an added factor called "cost efficiency."

[zero]

The power rating on the laptop supply is max power not what it draws.

For anyone that cares to read actual test data on electric power supplies like used with lap-tops there is a lot of test data available. It's a hot subject with the EPA. The AC to DC power supplies vary from 40% to near 90% efficiency and most out there are on the low end. No sense posting anecdotal specs unless there is an actual make and model number of a specific power supply (EPS). Here is some info and links:

External power supplies are devices that convert ac power from a wall outlet into lower voltage dc or ac power to be used directly by electronic circuits. External power supplies come in a separate physical enclosure than the end-use product, and usually provide power to the device directly through a separate cord and plug. External power supplies are used to power a variety of electronic devices, including: laptop computers, printers, cordless phones, cell phones, etc.

More than 1 billion external power supplies are shipped per year, and the average American home has five to ten of these components powering devices in their homes. Despite the prevalence and importance of external power supplies, their energy efficiency can often be very low. EPA’s research has indicated that approximately one-third to one-half of the electricity that flows through power supplies is consumed in the power supply itself, as these power supplies are only about 50% to 70% efficient. ENERGY STAR has developed this new program in order to encourage the use of more efficient external power supplies in the market.

By 2008, the market share for ENERGY STAR qualified EPSs had reached approximately 50%, delivering energy savings of 5 billion kWh/yr and annual greenhouse gas reductions of 1 MMTC. That same year, a minimum efficiency standard went into effect for EPSs, mandating the ENERGY STAR performance level, and the ENERGY STAR specification for EPSs was made more stringent (EPS V2.0). Preliminary estimates indicate that the market share of EPSs meeting the current ENERGY STAR specification was greater than 50% in 2009.

F. Active Mode: The condition in which the input of a power supply is connected to line voltage ac and the output is connected to an ac or a dc load drawing a fraction of the power supply’s nameplate power output greater than zero.

G. No-Load Mode: The condition in which the input of a power supply is connected to an ac source consistent with the power supply’s nameplate ac voltage, but the output is not connected to a product or any other load.

H. Power Factor (True): The true power factor is the ratio of the active, or real, power (P) consumed in watts to the apparent power (S), drawn in volt-amperes (VA).

http://www.energysta...artners.showEPS

http://www.efficientpowersupplies.org/

http://www.energystar.gov/ia/partners/prod_development/revisions/downloads/computer/Version5.0_Computer_Spec.pdf

[zero]

Just jerking around a little I tested 5 power supplies from some of the laptops we have here. I tested for power draw when NOT even plugged into the computer. I.e., zero draw from the lap-top.

Lap-top power supplies when not even plugged into computer:

Toshiba # ADP-75SB AB draws .06 amp at 117 volts (7 watts)

Toshiba # PA3715V-1ACA draws .17 amp at 117 volts (20 watts)

HP # 608425-002 draws .25 amp at 117 volts (29 watts)

HP # 380467-005 draws .27 amp at 117 volts (31.5 watts)

HP # 519329-003 draws .27 amps at 117 volts (31.5 watts)

Note the best at 7 watts draws ½ amp at 12 volts DC

Note the worst at 31.5 watts draws 2.6 amps at 12 volts DC.

[waiter]

JD , Interesting. Were the last two DC power supplies being powered by 12 Vdc with no load?? nt sure what the last two items are.)

John Mc

88 Dolphin 4 Auto

[zero]

JD , Interesting. Were the last two DC power supplies being powered by 12 Vdc with no load?? nt sure what the last two items are.)

John Mc

88 Dolphin 4 Auto

No DC used in the tests. I just plugged the power supplies into an AC outlet and measured current draw. I only mentioned DC to show what the draw would be if DC was supplying the power and no added loss was involved.

The laptop converter with the most loss uses 3.1 watts when plugged into a 120 VAC outlet. If that was expressed in amps at 12 volts - it would 2.6 amps.

If DC was being used - to power an AC converter - there would be an added 8-10% loss inside the inverter.

[waiter]

I see, I wasn't sure if you had a DC-DC converter that you tried also. It does serve as a reminder that these devices do have phantom loads and either unplug, or have a kill switch to completely remove the devices from main power/

JOhn Mc

88 Dolphin 4 Auto

[zero]

I see, I wasn't sure if you had a DC-DC converter that you tried also. It does serve as a reminder that these devices do have phantom loads and either unplug, or have a kill switch to completely remove the devices from main power/

JOhn Mc

88 Dolphin 4 Auto

When I first got thinking about converting my house and barns to solar electric - I did a lot of measuring to see where electricity was being wasted. I had many surprises. The power converters - external and internal in much of the newer applicances and electronics draw a lot of current all the time. We wound up putting off-on power-strips on almost everything. Also - going by the bad advice from Consumer Reports - we replaced a good working freezer that was built in 1948 (International Harvester) with a new "high efficiency" freezer. Well? Ends up there is almost no difference. Went though the same with our kitchen refrigerator. We had a Kenmore that was bought new in 1979. Replaced it with a new top-rated unit - and almost NO difference in the power it uses per day. Funny that the next year Consumer Reports got busted for fudging efficiency #s for Energy Star.

I later bought a refrigeragtor high rated by Back Woods Solar. 12 volts DC and made in Sweden. Called a Sundanzer. This one IS amazingly efficient. 4Xs more efficient then our new AC Energy Star model.

With lap-top power supplies - many not only draw a lof current when computer is not even on - and waste up to 60% when actually being used. I suspect that is because computers are so variable and the cheap AC power supplies are not. A computer reading files uses a lot less then one processing videos, or burning DVDs, gaming, etc. So the Federal Government - and yes - Energy Star say they are adressing the problem. Hopefully now that Energy Star was caught with their pants down - they will be a little more honest. Previously, it was "pay to play."

[linda s]

This company makes energy efficient refrigerators in America. They also make full sized ones more usuable for a family

http://www.sunfrost.com/refrigerators_main.html

Linda S

[zero]

This company makes energy efficient refrigerators in America. They also make full sized ones more usuable for a family

http://www.sunfrost....ators_main.html

Linda S

Yes, the Sunfrost are also great units. As i recall the Sunfrost and the Sundanzers both use the same DC Danfoss compressors. Danfoss started out in Denmark. The compressors now are made all over the world. The Sunfrost has the box made in the USA, Not the rest of it.

[Maineah]

OK here is what I have found out using two Fluke calibrated meters. Most laptops use 20-30 watts no matter how they are supplied except DC to AC to DC during normal operations in order to find out how efficient the supplies are would require dismantling the computer or using battery voltage alone. Hands down a DC to DC supply is the best way to battery power a laptop by a wide margin. Idling current varies from brand to brand and even with in them from what I tested from 2.41 watts to 1.2 watts, the winner is a DC to DC converter built by Lund for Panasonic tough book computers at .5 watts. The worst idling current was an off the shelf 350 watt inverter in excess of 8 watts and I would suspect the current goes up with the size in watts and the amount of fans. The inrush current is 10 times the idling current on all of them due mostly to charging caps. The rated current of a laptop power supply is between 1.5 to 1.6 amps over a range of 100 volts AC to 200 volts AC so 235 watts that seems to be fairly standard. That leaves a lot of head room, the worst case I found was shy of 40 watts at 120 volts charging a pretty flat battery. Usually they are rated 200%. If there is any doubt here are some pictures. Note the voltage hit a 35 amp gel cell took running the computer using an inverter and a AC power supply.

The bottom line if you are going to use a laptop on batteries a DC to DC converter is the winner. Solar panel rating in watts is at the equator at noon. That rate is measured at 1000 watts per square meter being perfect so it goes down hill pretty fast as you move north and south. So just to keep up with 4 hours of computer use you would need to replace 100 watts. This won’t happen with a 100 watt rated panel in 4 hours of direct sun light double that you may come close..