Do the math for me...
...and then tell me how you did it. I have an appliance that is rated 130 watts at 110 volts (house current). How many amps per hour will this appliance draw from a 12 volt battery? TIA Eric
Forum Discussion
beemerphile1 wrote:
Lots of different formulas people are posting making a simple calculation confusing.
Watts stays the same regardless of voltage.
130 watts divided by 120 volts equals 1.08 at 120vac
130 watts divided by 12 volts equals 10.8 at 12vdc
Just different ways to get the needed result.
AC amps multiplied by 10 is a good empirical formula for use without calculator - if you already know AC amps.
To get AC amps, you may divide 130 watts by 120 or 110, doesn't matter because real AC voltage is often in between.
But beware the jumping decimal point - it's been known to confuse even the brightest minds.
