Inverter for charging a Laptop?

[AnD3rew]

Hi there

I have a 600w inverter, just a basic one not a sine wave one. Will this be ok just for charging a laptop? Won't try running it from this.

[Tombie]

I suggest you don't...


There are 12v laptop supplies (12v in whatever out)... About $70.00

Switch mode power supplies don't like Modified sine waves. You'll shorten the charger / laptops life.

[slug_burner]

You will be ok. If you already have it use it, if you don't get one of the dc to dc converters Tombie refers to. A switch mode supply just chops up the incoming wave form, I can't see why it would have to be a perfect sine wave.

[Blknight.aus]

anything short of a full sine wave inverter is likely to cause problems, either hard starting or not working at all with the inverter.

I've seen a 100w laptop switchmode power supply stall a 600w inverter.

jaycar have universal 12v laptop power supplies, I reccomend them.

In a pinch you can sometimes "trick" everything into working by putting a small (5-10% inverters rated output) incandescent bulb on with the inverter.

[slug_burner]

That sounds like the smarts in the either the supplying DC to AC inverter or the chopper in the AC to DC laptop supply are working against you and a resistive load such as a globe is enough to fool the supplying inverter to provide an output.

I have used a small power inverter, Ultraslim MotoMaster Eliminator, rated to 80W continuous or 100W for 5 minutes with the multivoltage battery chargers for cameras and have got away with it. I must check with the higher current draw of a laptop power supply.

[Tombie]

Big difference between got away with it and did it have any long term effects... :)

[Blknight.aus]

and its ineffecient...

why step from 12VDC-240VAC-(X)vDC when you can go 12Vdc-(x)vdc?

[drivesafe]

Hi Andrew, and just connect it up and see if the power supply turns on.

As posted above, some times, an inverter will not start if the load being applied is too small.

If this is the case with your set up, then spend the money on a DC to DC computer power supply.

I have used nothing but modified sine wave inverters for close to 30 years and have used at least 25 different units and never had a problem with either inverters or what ever I was powering from it, other than what was posted above, about the load not being big enough to get the inverter working.

In the early days, I use to use a rather large Inverter to run a stereo VCR that I used for outdoor recordings. The VCR did not draw enough power to get the inverter running so I had a 100w globe that I used to get the inverter up and running then I turned the VCR on, and turned the globe off.

Can’t get much rougher than that and I have run everything BUT power tools from inverters and never had a problem.

[TheTree]

Hi

I can't imagine a well built modern laptop power supply would have a problem with a less than perfect sine wave.

However I agree that for efficiency and safety you are better off with a DC unit powering your laptop. $70.00 is cheap insurance :p

Steve

[Tombie]

Perhaps because a well built power supply doesn't expect to be connected to a cheap square wave inverter :)

Power supplies are designed for relatively stable sine wave domestic power sources, not cheap, noisy low end inverters...

[TheTree]

Perhaps because a well built power supply doesn't expect to be connected to a cheap square wave inverter :)

Power supplies are designed for relatively stable sine wave domestic power sources, not cheap, noisy low end inverters...

Hi

Possibly, but if the design is like the one described here it seems there would not be a problem because the AC is rectified and filtered before being switched by the PWM circuit

Switched Mode Power Supplies (http://www.learnabout-electronics.org/PSU/psu30.php)

If it was me, I would shell out the $70 for sure ;)

Steve

[TheTree]

HI

Gives me an idea, I have a cheap inverter for emergency use, I might hook it up to a CRO and see what it looks like :D

Steve

[singlecell]

A switch mode wont have any issue with a cheap inverter, the first thing it does it rectify it to DC anyway. The worse you will get is a slightly lower voltage on your filter cap, which isnt an issue as you will find the PSU is probably designed to run down to 100volts.

But still as said using an inverter is very much the less efficient way of running the laptop.

[Homestar]

I've been using a cheap 300 watt unit from Dick Smith for 3 years in my work vehicle to keep my laptop charged - works fine, don't know what all the fuss is about.

We have 30 Sales vehicles running around with these units and we haven't had a computer power supply damaged yet....