I was going to upgrade my battery wiring from 6 gauge to 4 gauge. Pretty inexpensive to do that. But to upgrade all cabels (motor, controller) it is very expensive. Question is, can I just upgrade the battery connectors and not upgrade the others?
If you want the full benefit of the 4 guage cables you should change them all. If the battery cables are in bad shape you can just change those to 4 guage but changing them all would be best...
I agree with HRC, changing ALL the 6g cables to 4g is the way to go.
Think of it this way, a chain is only as strong as it's weakest link. If you leave any 6g cable in the high amp side of the circuit it becomes the weak point of that circuit.