Inverter

[Csail]

For running computers etc do i require pure sine wave or modified?

[William_H]

That is a difficult question to answer. I think when people start to answer from experience you will get stories of computer power supplies burning out and others that work fine. Perhaps your best bet is to try before you buy. However the queer waveform of the "modified sine wave" inverter can cause all sorts of problems with induction motors like that of a refrigerator where the higher frequencies of the square waves will cause heating of the motor a huge inefficiencies. So to be sure your computer is OK onn the inverter you choose you need to be able to measure the primary (12v) current to the inverter. Any gross inefficiencies which result in overheating of the computer or inverter will show as excessive primary current.

You should expect to use approx 1.4 to 1.8 times as much current into the inverter as the AC load in watts would indicate. This allows for inefficiencies but any more might indicate a problem.

I think if you can afford it you would be better off going for a pure sine wave inverter or if it is possible substitute the lap top charger for a power converter 12v to 18v or whatever is required.
Good luck I ma sorry I am not much help olewill

[Playtime]

Originally Posted by Csail

For running computers etc do i require pure sine wave or modified?

You don't actually need an inverter. A simple (and more efficient) way is to use a DC to DC converter like this one from Maplin

http://www.maplin.co.uk/Module.aspx?ModuleNo=36836

You need to check what input voltage your laptop needs (19V is quite common) and also what plug type (the converter comes with several different 'ends' but some laptops use a special plug that may be difficult to source).

[PS Ignore the above if you are using a desktop PC and not a laptop!]

[VicMallows]

I've had no problems whatsoever running the laptop (19v) via it's mains PSU and a cheap (£24.99 from NETTO) 150W inverter. This will most certainly not be 'pure-sine-wave'!

I've also used DC-DC converters (technically these are inverters also, but they change the output back to DC) with mixed results. I've had two of the very common cheap ones -(about 2inx3in, curved at top and straight at bottom) which both failed after a couple of hours.
I have another, smaller and rectangular, which has had extensive use over last year and works perfectly (this one has assortment of funny little plastic plugs which select the output voltage).

The DC-DC is more efficient, and has lower idle current that the 240v inverter, so generally use it for the computer. However, it creates a lot of interference if listening to internet radio relayed to the car radio! .....so have to change back to the 240v. Oh! Well.

Vic

[saxonpirate]

Agree totally with Playtime. You don't need an inverter to run a laptop aboard. Total waste of time and power. The 12 volt DC adaptor will do the job admirably. How can I be so sure? Because I use one when not on shore power, and have done for a few years.

Don't get sucked into the inverter jungle.... I nearly did. But after doing a lot of research and then listening to a friend who's an electronics engineer, I paid my tenner or whatever it cost then and have had trouble free 12 volt usage ever since.