Dodge Repair: 2001 Dodge Dakota SLT quad cab 4.7L

Question
A couple months ago I had to replace battery, positive and negative cables due to loss of all electrics. Ran fine for 4 months now I'm experiencing the battery gage dropping to zero out of the blue. Yet if I turn it off and let it sit for awhile then start it back up, the battery gage reads normal for a few days then drops right back to zero. I have had the alternator checked twice but have been told it is working properly.

I have noticed that when I have headlights on the radio starts blinking out of the blue on occasion but not sure if related.

Thanks for any help you can provide. I have 10 yes working as an automotive technician but this has me stumped.

Answer
Its more then likely the alternator.
Are you having some place check it out when the volt meter is below 12   or when its showing 14 volts charging?   Because it wont show anything is wrong  it is charging.
Kinda like going to a DR  u wont go unless u are sick at that time  u wont go if your feeling good.