The HF doesn't have a replaceable battery. Their website says it is a solar powered rechargeable battery and no part listed.
Another thing for old farts like myself to consider. The HF doesn't have a provision for holding corrective lens that are available at the welding supply stores. I had to make clips and tried two different lenses and even tried my own glasses. I still had trouble seeing.
With the Miller, I don't use anything and I can see the weld perfectly. I'm sure an appropriate, "Your results may differ" is needed, but it works great for me.
Spanky the finish has proven to be surprisingly tough, but I do use the provided storage bag when finished welding.
The Miller has two replaceable batteries and I am disappointed they don't last longer.
I can't imagine using a HF helmet again.
