Somewhere in the directions it says the batteries are not rechargeable, and that presumably applies to the solar panel as well (& I don't recall ever running across rechargeable coin-type batts...but that doesn't mean they don't exist). I'm guessing that the solar panel prolongs battery life by providing juice during the use of the helmet, and ditto the intense light from the welding arc.

I was going to use my helmet to look at the Venus crossing and discovered it was dead...after a few years of non-use in the garage. Ridiculous they don't make the batts accessible/changeable.

Cheers, and thanks for the info.