A:Answer It's a 24,000mAh battery pack, It's got enough charge to mostly charge an Ally X from dead to full. So should be good enough to give you close to an extra full charge. The two USB C ports charge at different rates though, with the main one closer to the outer edge charging at 45 watts, and the one closer to the center charging at 20 watts. So, use the outer USB C port to charge the Ally at the full speed this can deliver to it. Should be fast enough to play and charge without losing battery on the ally.
I have both this battery and the Ally X, and it works fine for me. Though I use this battery pack mainly to extend my playtime on a Quest 3 VR headset. :)
