Charging system

Hello All
I have recently purchased a 73 Dart Swinger with a 440
the car is very clean no rust at all, however the wiring is a mess.
My battery went dead, I charged it repaired some loose connections and frayed wires at the alternator.
With the engine running I measured 15 .3 volts at the alternator.
At the battery I measure 13.9
Is this right?
When I remove the negative cable from the battery the engine does not stall, but I can detect the rpm 's drop a bit
Appreciate any suggestions
thank you
Author: admin