Neat setup. That thing is powerful! I've never seen a 48v UPS..
Mine in work is 24v. with two smallish 12v sealed LAs. I think they are around 8Ah..
Your EV batteries must be pretty hefty eh?.?
Anyways, at work we have some AC cords with terminal lugs (also alligator clip versions)
that we use for
testing items before installing the AC wiring (filter, fuse, switch & etc).
We have a name for these test cables, we call them
Suicide Cables..
We never leave them on the bench after we are done testing.
They go back on the cable hangers. Too much chance of Murphy showing up..