12 volt fan vs inverter AC fan question

[acenjason]

OK, so I have a 10 watt 12 volt DC fan. I also have a few 10 watt AC fans. I thought I heard somewhere that 10 watts through an inverter ends up pulling way more than 10 watts off the deep cycle. So, it would conserve a bunch of power just using the 10 watt 12 volt fan. Is this true? Thanks in advance for any advice

[DaveVA78Chieftain]

10 watts divided by 12VDC = .83 amps DC

10 watts divided by 120VAC = .083 amps AC

Inverter efficiency is approx 90% and you use the watts value to convert between the AC and DC sides.  So, you determine DC amps pulled by the inverter by multiplying AC watts times a 1.1 correction factor

10 AC watts times 1.1 = 11 watts DC

11 watts DC divided by 12VDC = .91 amps DC

So, in this scenario:
the 10 Watt DC fan draws .83 amps DC
the 10 Watt AC fan draws .91 amps DC through the Inverter.

a 0.08 amp difference.

[acenjason]

Hey thanks:)