We recommend that you use the fulled B2 to power the quest2 when the quest2 battery is at 80% so that you can get the most out of your game time.
When the power of quest2 itself is still 80%, you can use the battery pack to power quest2. It will consume the power of the battery pack first, followed by the power of quest2 itself, so when the power of quest2 itself is enough. Just use the battery pack to power it and you can get the longest gaming time.
You should insert the USB plug first, and then magnetically attract B2.