I wouldn't say 8+. But several hours out of a 13" Macbook Pro
I've said for over ten years it's a cruel joke to call anything "portable" with a battery life of less than 24 hours.
TRS-80 Model 100, bitches. In the snow, uphill, both ways.
And I still love my Osborne I - sitting in a box in the garage. I hope to have space in the near future so I can unpack it.
Imagine putting a TRS-80 Model 100 on your wrist.
Really bulk up your arms...