I am not a professional mechanic but have had a lot of experience making cables with lugs that handle a lot of current in harsh environments. (I used to service automated welding and cutting robots and machines.) The lugs GM chose to use as shown in the video blew my mind. That is just asking for trouble.
With a soldered connection the weakest part of the cable is the area where the solder stops being drawn back into to the wire. At this junction you have a solid mass of wires and solder that will not flex connected to a flexible copper wire. Any amount of flexing at this joint will break it, period. The other big issue is that by relying on solder to make both an electrical and mechanical connection is that if that lug gets loose, it will get hot, the solder will get weak and the connection breaks faster.
The advantage that crimped connections have is that they do not have the weak spot at the solder/wire interface and they do not relay on solder for a mechanical bond. On a crimped connection that bit that wraps around the insulation acts like a strain relief. Its job is to take the mechanical stresses off the crimp on the wire itself. If GM had chosen to use a more robust strain relief they may have gotten away with the crappy soldered connection.
IMHO someone at GM needs to be fired over the choice to use those lugs. What a nightmare for anyone who has to maintain those vehicles.
One big issue with young engineers is that most have zero practical experience. Not having gone to college this really shocked me when I started working at a university. There are lots of bright kids who have never held a wrench in their hand and have no real-world experience to guide them. I can remember years ago trying to explain to a student how to use a feeler gauge, it was completely lost on him. Hands on learning is just as valuable as the theory but most kids don’t get the opportunity.
