Battery won't stay charged while running. Alternator is fine tho.

https://www.youtube.com/watch?v=AvLbb48tQPw&t=422s

I would have a load test done on the battery as there is a dead cell evident from the number of jump starts you need. Have an auto electrician test the alternator for charge rate and out put. check drive belt condition and tension.

Maybe it wasn't running long enough to charge up the battery?
Stop trying to jump it, when you are having problems with it dying, take the battery off and have it charged. And/or buy a $20 voltmeter to see what the battery shows. If it says less than 12 volts, it is discharged, and needs charging. A good battery that is not run down should have at least 12.5 volts. A new battery that is charged should have very close to 13 volts, maybe 12.8 volts.
When you have the truck running, check the alternator for charging. You put the voltmeter right on the battery and check it again. This time, with truck running, battery should show at least 13.5 volts. That shows the alternator is working. A good alternator will put out about 13 or 14 volts-the regulator will keep it from going any higher to prevent problems, like a melting battery or electrical parts burning out.
I would say get the charging system working right, then address the problem of dying at stop lights. That could be a carburetor problem, if the alternator is working.

These are all signs of a bad alternator. The car is running off of only the battery. The alternator charges the battery and keeps the car running. When the alternator quits charging the car will run fine until the battery dies. Then you can jump the battery and charge it, and the car will run fine until all of the electronics and lights run the battery down again.

did you check the battery cables. make sure they are tight.

Sounds like the inline fuse popped. It is located in the wire that comes from the alternator to the battery. The alternator is sending out the juice, but it can't make it to the battery. I sincerely hope that this gets you on the road again. Best wishes and God Bless.
Bryon

Check the Belt Tensioner. If the Tensioner is not Keeping the Belt Tight it will Drain the Battery Pretty Fast.Please Rate my Response, I need all the Help That I can Get! Thanks!

check the battery cable connections, are they clean and tight? This can cause the charging system to spike and go into the 16-17 volt range, the other thing is a problem with either the alternator or the voltage regulator, a diode that is failing can cause this issue.

Hi, I had simmilar problem with my 1993 JGC . I ran out of gas and it would not start until the next day. Then it will start and run until I put the brakes on tho stop and then it will die. It starts right back up. Ended up being the voltage regulator in the ECC/ECM. It is at the mechanics shop right now waiting for the ECC to come in.I will post a follow up.
have Fun,
David C

have the alternator regulator and diodes tested. sometimes when the regulators fail they allow ac voltage to go to the battery. ac voltage doesn't charge the battery properly (causes it to deep cycle and shortens its life) and causes all sorts of funny problems with the car. also make sure the battery is secured properly, vibration isn't good for them at all.