why does this car not hold a charge when the altenator and battery are good?

Something is probably draining the battery when the engine is off. Does the battery charge while the engine is running?

There is no output from the altenator 12volts running in battery only we've tried 3 altenators and nothing happens altenator fuse 140amps is ok

Have you measured the voltages on the smaller wires? One has to have voltage to run the internal voltage regulator.