The other day I started my 2020 Clarity FCEV and got a warning "Hydrogen Leak Detected. Power Reduced." Yikes. Drove to the dealer but they said I'd have to make an appointment to have it checked out. It seemed to drive OK and I figured that the warning would be more dire if it was unsafe to drive so I headed home to set up an appointment. But then I started thinking - I'd put an old, dead 12v lead-acid boat battery in the trunk a few days earlier, intending to take it to an auto parts store to recycle. I started wondering if maybe the battery could still be outgassing a little hydrogen. Next stop at the store to turn in the battery. The warning cleared immediately and hasn't recurred, so I'm pretty sure that old battery was the source of the "leak" detected by the car.
