Boy, are we getting spoiled!
I know it pains you guys to
ever see discharge on the ammeter, but the world is not going to end. (I think that's one of the reasons OEMs went to a voltmeter.)
Unless you spend most of your time at idle with the fans running, even a 50A alternator will keep the battery charged enough - if you have the fans thermostatically controlled. Think about this: It takes more than 4 hours at 10A to fully discharge most batteries. 10 minutes of that ain't goin' to hurt much.