Power Inverter for Charging Laptop in the car?

[V'sGlassSleeper]

I just wondered if anyone had purchased a power inverter for charging and using a laptop from the car's power plug (i.e. what used to be the "cigarette lighter plug") and if so, how well do you like it (and what brand did you get)?

It looks as though it's important to get a pure sine wave inverter rather than a modified wave inverter to avoid computer glitches.

[Byron Kinnaman]

I have a 75 Watt inverter that I've used for about 7 years to power a laptop, and charge lap top batteries. Anything in that area will work just fine.

[V'sGlassSleeper]

Byron,

Is it pure sine wave or modified? What brand and where did you get it? Thanks!

[Curtis F.]

I found that all 3 of the inverters I purchased to use as you describe produced RF interference. Made monitoring CB and/or amatuer radio almost impossible because of the interference.

I got a 12 volt direct to computer plug. It steps up the 12 volts to the 16 volts most laptop computers get from the AC power supply. Yes they are about double the cost of an inverter. The last a long long time. Mine is 8 years old and still working just fine.

Curt

[Byron Kinnaman]

Byron,

Is it pure sine wave or modified? What brand and where did you get it? Thanks!

My memory doesn't go back that far. I'll look up the brand when I get home, if it's marked on it. Probably got it at Wal-Mart or some such place. Bought it just for using with the LapTop, but have used it for a couple other things.

[Darwin Maring]

I saw a new type at BJs that hangs from the back of your car seat and it is advertised as working with a PC.

Because the PC runs internally on DC anyway, and just takes the AC 50 or 60 cycle sign wave and converts it to DC through a full wave bridge rectifier then filtered, I really doubt if it really makes a difference how clean the sign wave should be. You would have to look at it on a scope to see if it had any ripples in the DC.

[Per Walthinsen]

I have used modified sine wave inverters (the ordinary cheap ones) for several years. Tried to run my wife's sewing machine on one and the machine refused to run.

The information I have about lap tops running on these garbled waveforms is mixed. Some say they can and some warn agains it. Hard drives and scanners may refuse to run properly I have been told.

Because of the sewing machine fiasco I bought a 300w pure sine wave inverter in a brand popular with truckers (If anyone should know, they should know, right?). Samlex is the brand, Ebay is the place. The sewing machine smiled, started right up and quilted right along. Anything that runs off 120v house current will safely run on these little gems. Price was quite a bit lower than from Camping World or other RV suppliers.

[Linda R002]

We have used many, as we like to use the map programs on the computer while we drive. Since it is running and not just charging we found we need a higher watt. We tried 100w and that sizzled. We now have a Black and decker from Wal-mart that puts out 400 watts and don't have a problem as long as the auto is running. When the auto is shut off the still running computer draws enough that there is an alarm that sounds saying low battery which stops as soon as the auto is started again. We have used a hairdryer and coffee pot on the inverter a few times and they seem to run just fine too if we turn the auto on.

[V'sGlassSleeper]

We have used many, as we like to use the map programs on the computer while we drive. Since it is running and not just charging we found we need a higher watt. We tried 100w and that sizzled. We now have a Black and decker from Wal-mart that puts out 400 watts and don't have a problem as long as the auto is running. When the auto is shut off the still running computer draws enough that there is an alarm that sounds saying low battery which stops as soon as the auto is started again. We have used a hairdryer and coffee pot on the inverter a few times and they seem to run just fine too if we turn the auto on.

Wow, this is good to know because I would have assumed that a 400 w inverter would draw too much from the car battery, even with the car running (but what do I know about car batteries anyway?) I saw that Black & Decker model and will look into it further, as well as the Samlex that Per mentioned. Some of these units look awfully big, but if that's what it takes to safely charge and power a laptop, then okay.

Just checked Ebay and there's only a 600 watt inverter from Samlex, which is more power and more expense than I was looking for right now, so the B&D model might end up being a good one, but I want to investigate Curtis' suggestion too... so many different options!

Thanks!

[Greg A]

I've had a Belkin ACAnywhere for years to run the laptop in the car. Pretty inexpensive, 140watt 300 watt peak, probably got it at HD or Wally. I believe most laptop power supplies condition the output to the laptop anyway so never worried too much about the Inverter. Never had any problems running or charging the laptop with it for many years now and have never had any interference with anything from it.

[V'sGlassSleeper]

I found that all 3 of the inverters I purchased to use as you describe produced RF interference. Made monitoring CB and/or amatuer radio almost impossible because of the interference.

I got a 12 volt direct to computer plug. It steps up the 12 volts to the 16 volts most laptop computers get from the AC power supply. Yes they are about double the cost of an inverter. The last a long long time. Mine is 8 years old and still working just fine.

Curt

Brand? Store? Price range? Any additional details would be great!

[V'sGlassSleeper]

I've had a Belkin ACAnywhere for years to run the laptop in the car. Pretty inexpensive, 140watt 300 watt peak, probably got it at HD or Wally. I believe most laptop power supplies condition the output to the laptop anyway so never worried too much about the Inverter. Never had any problems running or charging the laptop with it for many years now and have never had any interference with anything from it.

Cool... Belkin seems to be a decent brand. They manufacture surge suppressors and power back-ups as well, so should know what they are building. I will look into it, 'cause I ain't lookin' for anything real' fancy, just want something that won't fry the laptop and create frizzle-frazzle on the radio. Thanks!

[Kathy R Lewis]

I just wondered if anyone had purchased a power inverter for charging and using a laptop from the car's power plug (i.e. what used to be the "cigarette lighter plug") and if so, how well do you like it (and what brand did you get)?

It looks as though it's important to get a pure sine wave inverter rather than a modified wave inverter to avoid computer glitches.

Hi Val...I use a power plug in my van to charge the batteries for my tools for work... Mine says it is a mobile plug 175 - it has a little fan in it that runs as it is charging my batteries... I am using this to charge different wattage of drills and saws, anywhere from 7.2 V to 18V. I do not have a laptop so cannot help with that end... but I understand the sine wave inverter is the best. If you look at www.carmanah.com you may get some information... I have their information for the solar panel system I want to put on the boler for next season.... hope this helps some.... Kathy from Ladner, BC Canada

[Byron Kinnaman]

As promised here's the skinny on my old inverter.

Wagen Tech.
75 watt continuous output
150 watt peak.
Made in Taiwan.

The main thing is to check the power supply "brick" for power needed. Little above that is good. A lot above is ok, but not necessary.

[V'sGlassSleeper]

Looks like everyone has tried something different that works, so there are a lot of good options out there--thanks, everyone, for the response!

[Brian B-P]

I doubt Belkin makes much of anything. Like Black Box, they're generally a brand name for stuff which they buy from the actual manufacturer. As a result, quality is inconsistent... but for all a power adapter has to do, I would guess that they would be fine.

Targus is a more common source for power adapters, especially universal output (use an interchangeable tip to match your device) and universal input (takes 12VDC, 120 to 240 VAC, 50 to 60 Hz) supplies intended for travelers. There are various other brands as well.

We used an older 120VAC input (only) Targus power adapter with a laptop for some time, and had no problems.

If you use the stock AC-to-DC supply that comes with the computer, and only need an inverter to get from 12VDC to 120VAC, I would expect just about any one with enough capacity to work fine. An inverter would only take as much power as it needs, so you can use one which is bigger than necessary... although it takes some "overhead" for itself so you don't want to go wildly big.

[Pete Dumbleton]

The low-voltage shutoff or alarm with the larger inverters is as likely to be the wiring to the cigarette lighter as it is to be the load.

Very little equipment one would take RVing needs anything but the inexpensive inverters; as Darwin pointed out, something like a computer runs on DC and the brick or wall-wart can accept a lot of variation. Mine, for example, runs on 100-240Volts and 50-60 Hz. I do, however, take the precaution of unplugging the brick from the inverter before starting or stopping the engine to avoid spikes.

I keep a 75W Vector from Wally in the glove box for small stuf.

[V'sGlassSleeper]

I looked at the VAIO and it states only 19.5V DC, which is what in terms of watts, I wonder? Would a 160 watt DC to AC power inverter be enough?

[Curtis F.]

This is what I use Targus power adapter.

Need 2 values to figure watts. Volts and amps. On the AC power supply that came with the computer there are two sets of values. One set is input, should be 120 volt and ? amps. Important for getting the correct match is output. Will be 19.5 volts and ? amps.

A 160 watt inverter should be able to support all but the most power hungry laptop. I have a power hog and it needs 150 watts AC to supply 75 watts. DC. Lots of heat generated in the process. By going direct DC to DC I save much of the conversion loss. I haven't got my adapter handy, but it draws a couple extra amps at 12 volts and outputs 16.5 volts at 4.5 Amps or ~75 watts.


To figure the size inverter, you need to multiply input vots times amps. That will give you a number that is watts. Any inverter with a larger continuous output will work. Problems do develop because the power outlet ( used to be cigarette lighter ) is not wired to carry a heavy continuous load. It is very easy as others have indicated to attempt to draw too much power thru the small guage wire.

Curt

[V'sGlassSleeper]

This is what I use Targus power adapter.

Need 2 values to figure watts. Volts and amps. On the AC power supply that came with the computer there are two sets of values. One set is input, should be 120 volt and ? amps. Important for getting the correct match is output. Will be 19.5 volts and ? amps.

To figure the size inverter, you need to multiply input vots times amps. That will give you a number that is watts. Any inverter with a larger continuous output will work. Problems do develop because the power outlet ( used to be cigarette lighter ) is not wired to carry a heavy continuous load. It is very easy as others have indicated to attempt to draw too much power thru the small guage wire.

Curt

Thanks, Curt,

The AC power supply states INPUT: 100V-240V 1.3A-O.6A 50-60Hz
So is it as easy as that being 130 watts-144 watts since there's a range given?

OUTPUT: 19.5V 4.7A

I would hope that just charging up the battery or trying to locate a campground won't overload the circuitry.