Simple check!
When you have the engine running, unhook a battery cable.
If the engine dies, it's the alternator.
If it stays running running, it the battery.
Since it is a 1950 that has been changed to 12V, there could also be a wiring issue. Ground!

Don


1967 GMC 9500 Fire Ladder Truck
"The Flag Pole"
In the Stovebolt Gallery
1946 2-Ton grain truck
1946 3/4-ton pickup,
1953 1-ton pickup
1957 1-ton flatbed dually,
1954 Pontiac Straight Eight
Of all the things I've lost in my life, I miss my mind the most!