I think if you held down the trigger, put the chain to wood, and never let up, you’d probably get 10-15 minutes. If you’re cutting, repositioning, moving, it seems more like 30-40 minutes. The battery that comes with the chainsaw is 80V peak, 72V nominal, 2 Ah. Charge time is 30-40 minutes depending on how hard you worked the battery and how much it needs to cool down before accepting a charge. There are battery sizes ranging from 2.0 Ah for $129 to 6.0 Ah for $359. Not inexpensive, but powerful.
I’ve been sharpening the chain on the bar without flipping it. When I replace the chain I’ll flip the bar. This is the sharpener I’ve been using. Very nice. https://www.timberlinesharpener.com/
Wood cutting is something I only do when wood falls in my lap. It’s good exercise. Though there are several pieces of property in the family where I could cut as much as I want, I don’t go out of my way looking for it. It just appears. People hear you burn wood and they call to get rid of a yard tree that is already cut up or to get rid of a stack of split wood because they converted their fireplace to gas. It’s nice to have friends.
Ken