That continuity check is a bit too simple though (it might miss a high-resistance short). A proper insulation resistance test with a megger is what the manual would call for, honestly.

My buddy had a similar mess in an old ranch house. He ended up cutting the pad into strips and building it up like a ramp.

Wait, did you check the battery health after you swapped it? Honestly, I've done a few of those swaps and the new batteries are never as good as the original. They might hold a charge at first, but they degrade way faster. Tbh, I wouldn't trust that old rating to still be true with a third-party part. It feels like a temporary fix that just proves the point about planned obsolescence.

But what if your bin just got lucky with airflow?

Yeah that's brutal, I'd look at a rock drill attachment for a demo hammer, way less kickback on that hard stuff.