IOW, if the battery was fully charged at the beginning of each test, would the hp required to merely maintain a charge be the same for both alternators?  That's what I was thinking. An alternator will never generate more current than is needed by the demands of the electrical system. The 37 amp alternator and the 50 amp alternator will put out the same current when connected to identical loads (up to a point). If the load is sufficiently large, e.g., somewhere above 37 amps, the 37 amp alternator will hit its limit while the 50 amp alternator will continue to deliver .
1968 Charger R/T, 440 Auto, GG1;
1969 Super Bee, 383, 4-speed, T5;
1969.5 Road Runner, 440-6, 4-speed, 96;
1970 Duster 340, 4-speed, EV2;
1970 Charger R/T SE, 440 (496), Auto, EB3;
1970 Dart Swinger 340 (416), 4-speed, EV2;
1970 Corvette coupe, LS5, 4-speed, Daytona yellow;
2000 Corvette coupe, LS1, 6-speed, Twin Turbo, Torch red.
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