I had a weird deal where my charger failed (covered under warranty) but symptoms were so weird I decided to replace my 12v battery as a first step. Long story short, maybe didn't even need a battery-- it was my charger. Cost was over 4K to replace (covered under warranty), but when I thought I needed a 12v. Went to a Bi-Mart store here in Oregon where their prices are unusually good for car batteries. I asked the attendant for help and they strongly told me they had nothing for Honda Clarity. I ended up buying a real Honda battery from my dealer for about $200.
Anyway, looking backward, is there such a thing as a normal 12v car battery that doesn't work with Clarity? I can't really imagine any standard car battery that doesn't work. It seems far more likely "Honda Clarity" isn't listed in their reference book.