The problem you’ll face is that this battery life is in equal measure software and hardware, at least in the intel days.
Running windows in boot camp drastically cut battery life.
Running windows in boot camp drastically cut battery life.
My point was that, and I say this from experience, if you get 8 hours of battery life on a MacBook running macOS you won’t get 8 hours running windows. You will get less, sometimes significantly less.
The person I originally replied to wanted to get a MacBook and put windows on it because the MacBook gets such great battery life. If they do put windows on it, the battery life won’t be so great anymore.