That would be my oversight - we tested it but didn't post it. Will update today! With the test the 15" MacBook lasted for around 4 hours, BatteryBox on its own

That would be my oversight - we tested it but didn't post it. Will update today! With the test the 15" MacBook lasted for around 4 hours, BatteryBox on its own did about 2 hour 20min. It's the equivalent of 58% of the battery, or 55Wh (the 15" MacBook has a 95Wh battery).