How long can a 500 operate an appliance that draws 4.5 amps @ 12VDC?
Dean
Member Posts: 1 ✭
Answers
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Without any losses for efficiency ... it should last a little over 9 hours. However, that is a pretty big load.
500 W-Hr / (4.5 amps x 12 VDC ) = 500 W-Hr / 54 Watts = 9.25 hours.
If you have experience in determining the efficiency loss, then the formula becomes ...
500 W-hr x (Eff%) / (4.5 x 12) = hours.
You should expect greater efficiency losses when using the regular plug outlet instead of a 12VDC outlet. More power is lost when creating the sine wave output. I have heard the efficiency of the power plug outlet is 90% and I have heard it is 69%, but I expect it is somewhere between these numbers. The RMS output for a standard sine wave is 70.7%. I don't know if that correlates to efficiency or if it is part of the calculation.
