I have a laser printer that I've been wanting to use on the go in the car with an inverter.
The power consumption section in the printers manual:
Average operating mode Less than 310W
Ready mode Less than 30 W
Power save mode Less than 1.2 W
Power off mode Less than 0.45 W (0.1 Wc)
I bought a 500W inverter for the car thinking this would be adequate. I connect up the inverter and the printer, the printer turns on, and then just as it hits its warm up process the inverter trips and everything stops. My first thought is that the cars wiring doesn't like pulling ~500W through the cigarette lighter socket... even though the fuse didn't blow. I then connect it directly to the battery under the bonnet and the same thing happens. Out comes the multi meter, I set it to measure DC amps and connect it in series between the car battery and DC side of the inverter and press the power button on the printer watching it intensely for a spike just before it dies. As expected the multimeter reads something like ~7.3x.
Now, my question is, how many Watts is the printer using at this point in time?
- is it 12V (input voltage) * 7.3A (input amps) = 87.6W
- or is it 230V (output voltage) * 7.2A (input amps) = 1656W
- or something else?
It seems right to multiply the volts and amps using measurements from one side of the inverter (1.) but it can't be using 86.4W otherwise I wouldn't have an issue. However, multiplying a measurement from one side of the inverter with a measurement from the other side (2.) doesn't seem right, but it's giving me an answer that seems more realistic to me.
Any clarification on the matter is gratefully received.