On Thursday, July 9, 2015 at 5:47:23 AM UTC-4, robobass wrote:


I just bought a 200/300Watt 230v inverter. I attached it to a car battery on the bench (nothing else attached) and plugged in a few lamps. The output measured 330v with loads of 50 and 150 watts. The lights did seem brighter, but not excessively so. The voltmeter is a cheapie, but seems generally accurate. I know that these devices produce a modified sinewave, and I should expect a different reading, but I thought the reading should be lower if anything. Is this inverter a dud, or do I just not know how to measure?

Thanks

Obviously not a dud as it does produce AC. But the real question is does the inverter do what you bought it to do. And if so why do you care about the voltmeter reading? If it is just that you are curious why the voltmeter reads high, I think you need to see the waveform on some kind of a scope.

The suggestions to compare heating water and comparing lamp filament brightness will let you know what the power output is.

Dan