No.   Your charging system has a certain capacity.  The generator/ alternator will have a rating, but it is typically a maximum rating, which will only be realized at high RPM.  So if you just tour, you can use that rating, subtracting the wattage or current of everything else on your bike, and see what you have left over.  However, if you don't keep the revs up, you start discharging the battery, which is bad for the battery, and sometimes makes it so you can't start the bike again.  Whoops.