If you're planning for longer run times on the new GH3 camera, here's the DC Coupler needed to work with an external power source. This dummy battery is required to work with many different external power solutions, or with the Panasonic DMW-AC8 Power Adapter that connects directly to an AC outlet (wall). This is the first DC Coupler adapter i've seen made available for the GH3 and found via eBay (click here).
Panasonic GH3 DC Battery Coupler External Battery
@CV - Yes they share the same batteries.
Assume this works with GH4 too?
@Caleb - As long as you can get the voltage to be compatible, you can use any type of battery.
Could one use this in conjunction with a NP-F mount external battery solution?