2012 Chevy Volt Battery:

"At some point I realized I had the 5v and GND wires swapped, long enough for the wires to start warming up."

🤦‍♂️

Now it comes out.

Brave to finally admit a little fact that should have been the first sentence in this thread.

I doubt it. If it had protection, the wires wouldn't have gotten warm.

"If it had protection, the wires wouldn't have gotten warm."

Um...it no longer works?

Notice they are concerned about overheating, not about protecting your inverter. The rules are concerned about fire, not wallet, protection.

Max short circuit is voltage divided by battery impedance. It's really not something you ever want to do to a lithium battery....a lead acid will tolerate it.

Detailed fuse datasheets give that max short circuit current. Finding the battery impedance could be roughly inferred by voltage sag at high current draw.