Q: Is the PowerPack 20000 fully compatible with the new 2018 MacBook Pro (15-inch)?
A: Yes, it is. Please note that the new 15-inch 2018 MacBook Pro comes with an OEM charging brick rated for 87W. The PowerPack 20000 can deliver up to 45W (at 15V) to the MacBook Pro. During light use, 45W is adequate to sustain the power consumption of the MBP and even charge up the laptop's built-in battery. However, when the MBP is running power-intensive applications, such as some serious number crunching and graphics rendering, 45W from the battery pack alone won't be enough, and some additional power will have to come from the built-in battery of the laptop. Still, using this battery pack will noticeably extend the battery life of the 15-inch 2018 MacBook Pro.
It is also compatible with the 2017 version of the 15-inch MacBook Pro.