Mad electrical offers these numbers for the internal regulated 63 Amp 10SI.
The available output at a 680 rpm idle is 35 - 40 Amps
rpm required for maximum output is 1275 - 1325 rpm
Remember that alternator output current is determined by the needs of the battery. Voltage is controlled at a constant level by the voltage regulator.
They consider the typical alternator output to be about 3-5 Amps while driving down the road with no lights or AC. It doesn't matter if you have a 30Amp or a 130 Amp alternator. That's all the battery needs.
