Laptop and Modified Sin Wave Inverter

yep,

havent noticed any issues. Like you it was the right price. Only use it occasionally, although looking at purchasing a 12V power supply for the laptop. Fairly cheap.

Have used to charge camera etc and they all end up charged, so there cant be too many issues. Im sure that someone will have a clinical answer for the cons of using mod sine.

good luck

Hi phillowe

I have not been using a modified sinewave inverter but I have been told a pure sine wave is the only way to go to maintain maximum battery life for a laptop (and apparently mobile phones).

I received this information from a 12 volt retailer who made this claim based on his recent experiences and personally, I have no first hand knowledge.

However, laptop batteries are not cheap and premature failure (if due to a modified sine wave) may make it worthwhile spending the extra on a pure sinewave inverter if the primary use is for laptop battery charging purposes ... and ... if you wish to believe the technician I spoke with.

I'm sure others will have some experiences to quote .....

I use one for charging phones, lectric shaver etc. Lappy has the real 12v supply. No ill effects yet.

If you are using an inverter to go to 240V AC then the laptop wall power supply which out puts depending on the laptop make ~18V DC (all are DC at the back of the laptop) I can’t see how it could possibly make a difference as the wave is only at the 240V wall power supply unit, its DC at the laptop. Using inverters is a really horrendously in inefficient (read sucks lots of Amps) to go to any DC powered device starting from 12~24V DC battery. But I guess it may be cheaper than the several car kits ipod phone laptop. I suppose it depends on weather battery life or cost is critical factor

I got 400w from the ebay - the same as Jcar sells in their shop and didn't
had any problems at all. I am running it with 4 outlet power board connected
to DVD player for kids, Laptop and charging camera batteries... It has
been in a car for more than a year now, running 24x7...

The 240V supply which came with your laptop will be a switch mode PSU. Because of the way switch mode supplies work they are quite happy to operate with a wide variety of input waveform shapes and frequencies and will convert the triangular wave from your 12V to 240V inverter into smooth DC for the laptop. The laptop won't have a clue whether it's running from a 12V or 240V, pure sine wave or triangular (modified sine wave is a marketing term and has no technical value) inverter or the mains or a generator. I ran my Dell notebook from a 300W DSE inverter for ages.

Linear power supplies and things with motors in them may well be upset by triangular wave inverters and should be used with caution. Additionally, for reasons I am not aware of, I have had one make of the new high efficiency lamps blow up when running from my DSE inverter - GE lamps, however, work fine???

Mike Harding

Hi,

Have run a number of Toshiba PCs on my modified sine wave power supply. Now have an ACER have had no problems. Also use it for Pentax camera, Gamboy, numerous mobiles the list goes on.
If anything was to suffer from a non pure sine wave it would be the power supply supplying the DC voltage and not the end product.

Garry

Hi phil,

Most laptops will charge off a modified sine inverter but I have found that you need a 500w unit for most of them.

I supply 500w units for laptop use because the switch mode chargers supplied with new laptops require a large start up current and the smaller inverters will overload.

Regards Derek.

Autopro and Jaycar sell a $50 12 volt lappy supply. Ours works fine on two different laptops.

Cheers

Pete

Hi,

I run an IBM thinkpad in the car. It has a high power drain (7.5 amps). Originally I was using a cheap 150W modified inverter and found the overload going off regularly.(not sure actually whether it was the overload or the low battery warning). It would seem to run the laptop if the battery was charged but didn't have the grunt to run it and charge the battery at the same time (also worse at night when I had the lights on etc and ok while I was motoring but warning would go off when idling at lights etc).

Not sure if it was a co-incidence but my battery pack on the laptop recently died (new one about $100.....no generics would go to 7.5 A). Who knows...could have been due to use in the car in this manner?

I now run a 300W pure sine wave inverter and haven't had any issues. Not sure if it is the extra watts or the pure vs modified that is the issue but I would suggest you are better off spending a bit more than the $40 or so for the cheap 150 Watters. Got the 300W pure for not much over $200.

Hope that helps
Trevor

Phillowe

Go down/to Dick Smiths and get yourself a thing called a KERIO.

I looks like your normal( 230/19v) two leads plus transformer pack that you get with your computer, but in a smaller version.

They are made for 12V source, running of computers.

Most laptops need somewhere around the 18/19v mark at 4.5amps and the KERIO comes into its own as it specificcaly designed for this purpose.

There are surges, spikes, dicky inversions/conversions etc etc etc.

You are in fact protecting an investment of approx $2000 with a $80 item.

Hi phillowe,
My experience with this is different to most others comments in this topic. We have an Acer Laptop that was only 12 months old at the time.

I checked the Laptop charger and based on it's ratings it would be drawing a maximum of 75 watt. (I'm an electronic engineer so I know how to work these things out).

Based on that, I thought, yep a 150 watt modified sine wave inverter will do the job, so of to Jaycar and bought one.

Packed the wife and kids up and off we went. Plugged in the Laptop and the kids were set up watching a DVD.

About an hour later the inverter alarm came on and I duly pulled over. The inverter was too hot to touch so I turned it all off and let it cool down.

It was a hot day, so I thought, that perhaps it had over heated as it was in the sun in the back.

A couple of days later when it was much cooler, I tried it with the Laptop and after an hour it overheated again.

When I got home, I did some basic checks, and found that the Laptop was pulling about 60 watt.

I then loaded up the inverter with a 75 watt globe and let it run for a couple of hours. It was barely warm.

I took the inverter back to Jaycar and told them of the problem. I was advised by the shop assistant that the modified sine wave inverters should not be used with switched mode power supplies such as Laptops.

The reason being (and although I'm an electronic engineer, I'm not sure I understood his explanation), was that the peak current at the switching point of the waveform exceeds the device ratings (the switching transistors in the inverter). He also suggested that it would be "hard" on the Laptop charger.

So after a bit of discussion they took back the modified sine wave inverter and proceeded to offer a pure sinewave one for a small discount on their RRP.

I bought this, somewhat unhappy that I had to pay quite a bit more for the pure sinewave unit, and I was sceptical that it would work.

I subsequently tried it it out with the Laptop. Many hours and DVD's later, the pure sinewave interver gets warm, but does not alarm, so it's OK.

Now about three months later, the Laptop charger stopped working and blew the 240V fuse in the house.

The input side (240V), had gone short circuit.

Now it's only conjecture, but maybe this was a result of the "stress" it was placed under when used with the modified sinewave inverter.

Many people will say that they have had no problems. In my case, perhaps the rating of the inverter was too close to the power being pulled from it by the Laptop when considering the "the peak switching currents". Perhaps a higher wattage unit would have been alright. Don't know.

I'll let you make up your mind.

Cheers,
Mal

Slightly off-topic

If you're running external power source via inverter etc, remove the battery.
The continual discharge/recharge significantly shortens the life of the battery.