After powering my Sony HDR-AS30V helmet camera for nearly all of this year’s riding, the Batmax NP-BX1 lithium batteries still have roughly 90% of their original capacity:

Those are hot off the Official Batmax charger, which appears identical to other randomly named chargers available on Amazon.
They’re holding up much better after a riding season than the DOT-01 batteries I used two years ago:

Empirically, they power the camera for about 75 minutes, barely enough for our typical rides. I should top off the battery sitting in the camera unused for a few days, although that hasn’t happened yet.
Of course, the Batmax NP-BX1 batteries I might order early next year for the new riding season have little relation to the ones you see here.