On Monday, September 19, 2011 at 11:12:51 PM UTC-4, GeoLane at PTD dot NET wrote:
Yes, the solar powered welding helmet does have two coin cell
batteries in it. They're sealed in the lens's case. Someone wrote
up the procedure for replacing them a year or so ago, and I didnt'
save the page then. I googled for it, but came up empty handed. Did
anybody here save that web page, or has anybody here disassembled
their HF autodark helmet to replace these?

RWL

Excellent Youtube "how to" https://www.youtube.com/watch?v=7hRLeXKXuuE