Nyko’s Power Pak is a backpack battery for your DualShock 4 that aims to double the battery life without messing with the ergonomics.
The DualShock 4 might be the best controller ever, but the battery life, especially compared to the DualShock 3, isn’t great. The Nyko Power Pak stores 1000 mAh, the same charge as the one inside the DualShock 4.
The Power Pak clips into the microUSB port of the DualShock 4, and the weight difference is imperceptible. Whether ergonomics are truly kept “intact” is a matter of peerspective- your index fingers will brush against the battery sometimes when pressing the triggers, and your middle fingers are pressed outward by the battery. None of this impedes gameplay or comfort (at least for me), but purists may balk.
Whether the Power Pak is for you comes down to a lot of factors, not the least of which being how convenient it is for you to play with the controller plugged in to charge with your gaming setup, but short of using a wire, it’s the most convenient way to extend the DualShock 4's battery life so far.