Wizard - We are saying the same thing - just your way of saying it makes better sense...
25AMPs x 2.9hours = 72.5AHs Thats pretty close to the 85AHs rating for the battery mentioned... This much current drain however would drop the 85AH battery to 0% state of charge which you don't want to do.. Adding up all the current drains times the hours of use is really a better way to look at it...
If the total amps added up to 25AMPS then it would only be 2.9 hours of use before dropping the battery to 0% state of charge...
since I measure my actual current draw at my Battery Monitor Panel in AMPS all the time its easy for me to see how much current is being drawn...
just saying...
Roy Ken