Official batteries for these fancy things cost a tad too much to keep a collection of, but one is never enough for a proper field day. To top that off, the smart camera only cold boots via batteries with an official ID chip, so using aftermarket ones straight is impossible, unless…
You get one of these, generic dual battery grips. This particular is MeiKe brand, but I’m sure they’re all basically the same. Besides being a grip with a vertical shutter button (via external cable), this thing allows two main things: use 2 batteries simultaneously, and use 3rd party batteries via official cold boot trick.
Procedure goes as follows- when you cold boot the camera, you must have official Nikon battery in either slot so its chip responds to camera’s check. After that, you may replace batteries in any way you want as long as at least one is always inside the grip and provides power for the camera to avoid cold-booting.
Mounting is very simple as well- pull off the stock battery door and store it in the connector portion of the grip, insert the grip into the battery slot, and tighten the locking screw via a large dial. The grip has a secondary tripod mounting hole, so you don’t lose that function at all.
Oh and lastly, grip and 2 oem batteries cost me, shipped, less than one original Nikon one costs.