when running the volt gauge shows the car chargin at what i would guess to be 10 volts but it runs and for a while will start right up over and over but then suddenly the battery will just get drained and we will have to jump start it why? its got an 85 alt any ideas?

 

It is not charging.
I assumed you confirmed the low voltage right at the battery with the car running and checked all the electrical connections for integrity.

Looks like the alt needs some repair. Either the brushes or the regulator or maybe another problem.
I repaired an '86 alt and it is pretty easy. I believe the alt you have is the same...
Here is how to bench test it and do some minor repair:
https://classicoldsmobile.com/forums...tml#post236386

 

If your alternator is working properly you should have 13-14 volts at the battery with accesories (lights, wipers, heater fan etc) on.
10 volts is what you may expect from a battery not being charged, the load from the ignition system will drop the voltage.
Some systems require the warning light to work, if the bulb has blown the alternator won't work. I know this applied to several french systems and I believe also to some Delco systems as well.