Nope, no load tester other than the stuff original to the car but the old alts couldn't even supply those minimal loads without draining the battery when they were all turned on. If my napkin-math is correct the loads wanted about 42 amps, old alts could only do around 40, that left 2 amps to be supplied by the battery.
Alvin, if this is/was a vehicle wiring issue of any kind how come it didn't work with two 10SI alternators but works great with the new CS144 using every bit of the same original wiring? The only thing changed is the alternator itself, a new 5/16 ring terminal crimped onto the end of the original 10GA charge wire(1) and a CS144 connector plugged into the original 2-pin connector with spade terminals(2).
The idiot light in the dash works, has always been working - on at key-on, off as soon as engine starts. The big 10GA sense wire that parallels the main charge wire is only there to bypass any voltage drop in the main charge wire. It always showed minimal voltage drop (it was checked), because that wire does not carry any load.
(1) the original was good, only changed because new alt is a M8 stud
(2) this is temporary, I wanted to prove the new one worked before chopping off the connector