Hello

What size plug in invertor will run a Dell Studio on a road trip. Thanks Steve

Laptop power supplies are usually marked right on them how much power they draw.

Typical for a modern laptop is 175-250watts.

You need an inverter that'll handle that load continuously.

Check the marking on the inverter.

AD

Thank you Allan I will check that when it come in. Never thought on checking the usage on the machine.. Boon

I have a Dell XPS that requires a 230W charger. There is no DC adapter because the amp draw when charging exceeds 10 amps. I have a 1500 watt Cobra inverter and even with that much power, it trips out unless I remove the battery and run without it. If there is no cigarette lighter adapter available for your Studio, you're probably in the same boat.

Unless you have a "good" inverter that 1500w "intermittent"
rating tends to be.... how should I say this... So grotesquely over optomistic as to defy any expectation of honesty or shame on the part of the manufacturer.

You need to look at the "CONTINUOUS" rating
of the inverter.

any "momentary rating" that is greater than 3-times the continuous rating should be taken with a freight train full
of salt.

my "good" inverter is made by Tripplite and weighs 80lb. it is rated for 2500watts continuous, I don't offhand know it's momentary rating.

AD

AD

Good point; I'll check it. The thrust of my post was that the power draw of the bigger laptops exceeds the amperage limits of most if not all cigarette lighter circuts and a lot of people prefer not to hard-wire an inverter to the car. The best way to run them in a car without enough inverter is to remove the battery so as to bypass the charging circut and limit the current draw to only what is required to run the PC. Then you can use a lighter-duty, plug-in type inverter. OTOH, if you can get 2500w continuous from a cigarette lighter plug, I just learned something new, lol.

as an example of laptop P/S, I have a gateway M350.
It's power supply requires 175w of AC which is not quite an amp and a half

WATTS never change, a watt is a watt is a watt.

so to run a 175w device off the 13.7v nominal voltage
of a typical automobile lectrical system will take almost 13amps (12.77 if you wanna be precise)

assuming your inverter is 80% efficient (a reasonable estimate) is going to bump that up to 16amps (15.97amps)

16amps is a bit much for a 10-15amp cigarette lighter circuit to take for any length of time.

Personally I'm inclined to comment that even though a typical laptop suppy draws 175max, that presumes that you are actively using the computer (screen lit etc)
AND that the battery is near dead and is getting a
high rate charge, in which case the "worst case"
I have outlined above is a really worst case.

Typically I'd expect the draw to be ~9amps

Inverters only draw as uch current off the supply as they are required to provide to the load placed upon them.

They draw almost no power when there is no demand.

This is why most new cellphone "wall warts" use a "switching power supply" rather than the older style "Linear power supply" (with a chunky transformer inside).

the tiny ammount of power a linear supply phone charger draws becomes non-trivial when it's left plugged in 24-7-365

I drive truck and have run mine of with a small coleman invertor that plugs into a cigarette lighter I got at Wal-Mart. Has worked for 3 years now on an HP. I most of the time use my 1000w invertor that I have hardwired to the batteries when watching a movie. But I have never had the colman not work for anything yet.

Don't know about your Dell Studio, but my Dell Inspiron which links to my Oehler 43PBL at the rifle range works fine on my 400W continuous, 800W peak Vector inverter which plugs into one of my GMC's powerports. No problems in 6 years, no need to pull the battery either. And I think its Pentium 4 HT chip is pretty power hungry.

I have an Acer laptop and have run it from a 300W inverter for the past few years with no problems, but as mentioned look at the wattage of the supply.

And having said that, realize that you can fiddle with it if it is borderline by turning down the monitor and speakers and not leaving an unused CD in the drive, etc.

OK, let's stop and think about what we're doing. You want to take an inverter to change 12 Volts DC to 120 volts AC so you can plug in your power supply so that it can convert the 120v back to DC voltage for the computer. Since your computer runs on DC voltage, wouldn't it make sense to buy a mobile computer power supply to run DC to DC? Not only is it more efficient, but it leaves the high voltage out of the picture. Inverters aren't known for having clean AC power. Until you get into the high dollar inverters, most are not recommended for sensitive equipment. Just do a search for "mobile computer power supply". or here's the first link that I found.

power supply link

Nashcat

I would look at the bottom of the power adapter for the input power rating (ie: 120 VAC, X Amp) and go from there.

My biggest suggestion is to not go with a cheap inverter, but get one that is "true sine wave" rated. Square-wave or modified sine-wave inverters don't quite work right with any switching power supply.

quote:

Originally posted by Nashcat:
OK, let's stop and think about what we're doing. You want to take an inverter to change 12 Volts DC to 120 volts AC so you can plug in your power supply so that it can convert the 120v back to DC voltage for the computer. Since your computer runs on DC voltage, wouldn't it make sense to buy a mobile computer power supply to run DC to DC? Not only is it more efficient, but it leaves the high voltage out of the picture. Inverters aren't known for having clean AC power. Until you get into the high dollar inverters, most are not recommended for sensitive equipment. Just do a search for "mobile computer power supply". or here's the first link that I found.

power supply link

Nashcat

Presuming (facts not in evidence) that one is made to fit his laptop yes.

But often the 13vdc "car charger" is considerably more expensive than the AC supply that is typically provided with a aptop/notebook

Personally I have an OEM car charger for my current (Dell 15series) C2D notebook
They GIVE you the 117vdc charger with the notebook, the 12v charger is over $100.
mine actually also has an AC supply cord so it's really a dual-purpose "Travel charger"

THE rub is that no laptop/notebook I'm aware of actually runs on 13.2V nominal "car" voltage. My Dell for example requires 18-19Volts to actually charge, so the Car/travel chargers are infact inverters anyway.

The point to using a seperate inverter is for $40-ish you can buy an inexpensive inverter, use your exsisting supplied AC charger and go motoring with your portable computer.

Though I must comment I actually have THREE A/C chargers for my primary notebook. The (expensive) "Travel charger" mostly stays in the notebook case, The CHEAP
A/C chargers are already plugged in in most of the places I actually use my notebook.

Eventually I'll get another travel charger and hard wire it into my vehicle

AD

I use a cobra 2000 watt peak inverter in my semi it runs my laptop, microwave and I run a 1/2 " drill with no problems. If you buy a quality inverter with a little more peak wattage than you might need you will be good to go just remember to mount it with plenty of air flow to keep it cool.

quote:

Originally posted by boondocker:
Hello

What size plug in invertor will run a Dell Studio on a road trip. Thanks Steve

Another option is a smaller netbook; I take an EEE PC along with a smallish inverter and it's enough. I can run the GPS from an Sd card and the solid-state C: drive isn't at hazard if it falls on the floor...

There are power adapters made specifically to power laptop PCs from your car's cigarette lighter. They are not inverters, but instead produce the correct DC voltage for your laptop and they provide the plug that fits directly into your laptop. Below is a link to one such device.

http://www.tigerdirect.com/app...No=6455233&CatId=608

I would opt for one of these rather than an inverter.

quote:

Originally posted by Red C.:
There are power adapters made specifically to power laptop PCs from your car's cigarette lighter. They are not inverters, but instead produce the correct DC voltage for your laptop and they provide the plug that fits directly into your laptop. Below is a link to one such device.

http://www.tigerdirect.com/app...No=6455233&CatId=608

I would opt for one of these rather than an inverter.

Red,
It is STILL an "inverter" (though labeled as a DC-to-DC converter) because somewhere inside the unit it has to be converted to AC to accomplish the voltage increase.

DC-in to AC(inside) back to DC-out cannot be accomlished any other way.

I refuse to speculate about secret alien technology


beg to differ, if the voltage the laptop runs on is higher than 12.5Volts it IS an "inverter" because the voltage must be increased to run a 19volt laptop on 12v (13.2V nominal) vahicle power.

The way this is done is to take the 12-13V car power and using a low voltage inverter to upconvert it to the 17-19v required by most laptops.

This "upconversion" is accomplished by a switching transistor that generates Squarewave AC which is then "Stepped up" to the desired voltage plus an extra 1.5 volts then rectifies it with a diode-bridge back to DC

~1.2 Volts are "lost" going through the diodes
converting the AC back to DC.


Though I will admit that the way they work INSIDE is less then relevant to the majority
of users.

The REAL point is that a generic inverter as a common consumer item is typically cheaper than a dc-to-dc laptop charger.

And in truth if you investigate those units further most of them only supply 75-95 watts which is "ok" for charging the notebook, but charging it AND using it at the same time isn't gonna be "happy"

AD