Voltage, amps, and watts

Good grief, sound, for some reason, almost every post that I make, someone with an attitude, such as yourself has to chime in. I have reread my initial post 4 times and it is very clear. I know how to compute usage with AC electricity, listed a formula, and gave an example. I went on to post my confusion on battery usage time, when using an inverter, and also used an example to assist in computing usage time. And you still don't get it. You get PO'd and link in a meter that measures volts, amps, and watts, which has nothing to do with this thread. Using the device will list volts, etc, but that's the same info that's printed on the appliance and we're right back to my initial question; how do you compute usage time and how long will the battery last with the appliance plugged into the inverter. Now, that question has been answered twice, very effectively, I thanked everyone for the input, and I have not complained. Let it go. OBTW; you did post some good relevant information after the meter reference.