My wife and I went to the arctic circle on our honeymoon to ride reindeer in the mountains and see if we could witness the Aurora Borealis.

Recognizing how climate can affect devices, especially batteries.

I came up with a way to make an external battery adapter for my camera.

This also serves as a home dc plug adapter.

It lasted -17c to -25c over the course of 10 hours running 4k video and 4k photo with my Panasonic GX8 micro 4/3 mirrorless dslr.

Here is how I did it.

Parts List

- Panasonic GX8 Mirrorless Micro 4/3 Camera

https://www.dpreview.com/reviews/panasonic-lumix-d...

- DSTE DMW-BLC12 Replacement Li-ion Battery for Panasonic Lumix DMC-G5 G6 G7 GH2 GX8

https://www.amazon.com/dp/B00MEAMBQU/ref=cm_sw_r_c...

- DMW-DCC8 DC Coupler BLC12 dummy battery for Panasonic Lumix DMC-GH2 GH2H GX8 G6

https://www.ebay.com/itm/302072178916?ul_noapp=tru...

- 8.4v Rechargeable Battery Pack for Mountain Bike Light Bicycle Lights & Headlamps ABS Waterproof Battery-Replacement 4 x 18650 batteries choice 6400 or 8800 mAh [I chose 8800mah]

https://www.amazon.com/Rechargeable-Headlamps-Wate...

Step 1: Open the Battery and Remove the Battery Manager.

Here is the part we need from the battery pack.

This is the battery manager, in essence it will let the camera know that our external pack is legit for use.

Step 2: Open the Dc Coupler and Remove Blank Pcb

This is a dc couple found on eBay notice it has a totally blank and unprotected chip board.

I would not recommend using this out of the box, unless it was paired with a regulated dc supply perhaps.

We will remove the board and take the rest to the finish.

Step 3: Finding the Circuits Insert Points.

While testing the circuit the revelations were as follows.

I found that the capacitor that will be our positive insert point [Yellow rectangle] is at the center bottom of the board. It will need to be removed and the (+) wire of the pigtail will be soldered in its place.

There is a diode [Black "SSi"] beneath the coil and above the capacitor
[Yellow rectangle], that will be our negative insert point. It will need to be removed and the negative (-) wire of the pigtail will be soldered in its place.

Solder the pigtail to the insert points.