OT: Power Inverter

[Hawk]

Curious minds want to know.....Does a higher watt output inverter draw more power from it's source (car) than a lower wattage output?

[hubops]

Not until you plug it in ... John T.

[trader_4]

Not clear which scenario you mean:

A - Does an inverter rated 2000 watts draw more power delivering

1500 watts than a 1000 watt inverter would while delivering 500 watts? Of course the answer to that is yes.

B - Does an inverter rated 2000 watts draw more power delivering

500 watts than a 1000 watt rated inverter would while delivering 500 watts? The answer to that is probably just a little bit more, but it would depend on the designs and the efficiency. I'd expect if they were the same design then the larger one would probably draw just a tad more power, but not a significant amount. You could look at some spec sheets that should have actual numbers.

[Clare Snyder]

If you don't draw more power from it, the "overhead" of the larger inverter is marginally more than a smaller one.

[danny burstein]

Your question isn't quite clear but... I'm guessing that you're asking if, when you place a (for example) one hundred watt load at the end, whether an inverter rated at 500 watts will use more power than one rated at 150.

I've measured these in the past and the answer is... often yes. BUT there's so much variation in quality and efficiency and wave forms and power factor, that you can't just get an easy answer.

Inverters (or, for that matter, UPS'es) have two channels, so to speak, that cost them energy.

FIrst is the overhead in just keeping it running. Accepting for the sake of this discussion that both the 150 and the 500 watt rated units (well, actually volt-amps, but let's not go there...) are equally well (or badly) built and have similar circuitry, the overhead in the larger unit will be, well, larger.

The second is, of course, the demand of the end load. The 100 watt lamp (ignoring power factor and harmoincs and other head scratchers) will require that the inverter pull 8.5 amps off the 12V supply.

If both units are equally well/badly built, etc., etc., then they'll both pull the basic overhead, and then add in that 8.5 (adjusted way upward for inefficiency, etc.).

So short answer: The larger unit _will_ draw a bit more power simply because it needs more for the background overhead.

But again, there's so much variation you can't really tell unless you measure it.