Monday, Mar 05, 2007 at 14:18
Hi Phil,
Sorry to break the bubble, about 15 months ago I had a 150 W (Jaycar) modified sine wave inverter to run a laptop.
The laptop pulled approx 60 watt. After about 1 hour the inverter would alarm and shut down due to overheating.
I thought I had a dud inverter, so did some tests and plugged in a light (60W) and let the inverter run for several hours, no problems.
I checked current draw (12V side) and in each case (laptop / Light Bulb) the inverter was pulling approx 5 amps.
I took the inverter back to Jaycar and explained the problem. Despite the advertising in their catalogue, I was advised "dont use a modified sine inverter" for equipment with switch mode power supplies, which of course a Laptop has.
It "stresses" the inverter and also the switch mode power supply. Interestingly, the laptop power supply died approx 2 months later, and it was a short on the 240Vac side.
I exchanged the modified sinewave inverter for a pure sinewave unit and have not had any problems since.
Cheers,
Mal
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