In that case i would say some investigation of the cause is in order.
The charge wire can carry a lot of current. I would probably replace the whole length rather than trying to splice it.
Bring the alternator to the auto parts store and have the regulator tested.
If it is causing full output all the time the new wire will melt and overcharging will harm the battery.

 

the alternator post where you hook up the eyelet melted out of the alternator so there is no way to test it. I plan to get a new alternator and rebuild the wiring and give it a go. What do you think? It shouldn't be the voltage regulator right?

 

The regulator is internal.
If you replace the alternator you will be getting a new one anyhow.....

 

having similar issue, mine might be a lil easier though. I have an 86 f150 and the alternator has 2 connectors on it which I think I need to replace. They are pretty tore up and keep drinking batteries dry. It also doesn't have ground wire connected to it but I looked online and it says it's optional but I feel like it should have one because it has a screw in the back of it where it can go. Also can not find one of the connectors the smaller one. Any opinions on this are welcomed and appreciated

 

The 2G regulator and charging pigtails are commonly available.

If you are asking about the 'ground here to test' screw, do NOT leave it grounded.
It will send the alternator charging full field.
This will boil the battery dry and melt the diode board inside.
The alternator is grounded through the case to the engine.
Check the block to battery ground in the lower corner.