I really like my Gopro Hero 10 action camera. But when you are vlogging, the battery is draining pretty fast. Therefore, I decided to create a battery grip for extended recording time.

The housing is a simple design using Sketchup. It consists of several 3d printed parts which are easy to print even on budget 3d printers. Most parts are designed to press fit in order to avoid the use of glue and to be easily changeable. I recommend using ABS(+) but PLA and PETG will work too.

The electronics consist of a charging, a step up and a USB module. I decided for this modular approach to keep the overall package rather small. However, this means that you need to solder.

The electronics are powered by a single Li-Ion cell. I went for a single cell to keep the weight and size of the grip down. I recommend using a 21700 battery (up to 5000mAh) for longer run time, although a more common 18650 (up to 3500mAh) will also do the job. Overall, this should help to extend your action cam's battery life 3-5 times.

I hope you enjoy my design. Have fun and stay safe!

Supplies

simple 3d printer e.g. Ender 3 V2
.stl files for 3d printing
I recommend ESUN ABS+
Li-Ion cell e.g. 21700
USB module
DC step up module
TP4056 micro USB or USB-C
wire
M5 nut
2x M3 nuts
2x M3 12mm screws

Step 1: 3d Print All Parts

The battery grip consists of 6 parts

grip
battery caps (print 2x 21700 or 18650 - your choice)
head
USB ports cover
flap (print 2x)
Gopro mount

I tried ABS+ and PLA+. I used my standard printer settings with 40% infill and 0.2 resolution. You could print the Gopro mount with 100% infill as it is the most stressed part.

After printing clean and trim the edges of printed parts.

Step 2: Battery

Start with the battery, you can choose between 18650 and 21700
Use tape to stick the stripped end of the wire to terminal. Black wire goes to the negative terminal, red wire to the positive. Ensure that the other ends do not touch do avoid a short circuit.
Put the right sized 3d printed caps on top of the terminals. Ensure a tight fit.
Test the output with a voltmeter.

Step 3: Electronics

Remember to insulate wires when working to avoid a short circuit!
Solder the step up module to the battery. Black wire goes to Vin- and red wire to Vin+.
Use a small screwdriver to set the output voltage to around 12V (USB module needs at least 6V)
Solder another pair of wires to Vin (wires go to the charging module).
Solder these wires to the charging board. Black wire goes to B-, red wire to B+.
Check: the charging module's LED lights up when charging.
Now solder a wire to the step up module's output (Vout+) and connect it to a switch.
Solder a second wire from the switch to the USB module's input (+)
Now solder a black wire from step up module's output (Vout-) to the USB module's input (-)
Check: USB module's LED lights up when switched on

Step 4: Assembly

Insert the battery into the grip - it is press fit
Put the electronics through the head and the dedicated slots. The switch goes out of the front slot, both charging and USB module out of the back slot.
Then insert charging and USB module into the 3d printed USB ports cover and push it in the back slot.
Put the head on the grip. It is supposed to be a tight press fit.
Put the Gopro mount in the top cut out.
Install the flaps with M3 nuts and 12mm screws.
Insert the M5 nut into the Gopro mount

Step 5: Finished!

Now you are ready to go! For charging just connect the smaller USB slot to your mobile charger. For powering your action camera use a short USB-C cable.

I hope this instructable was useful for you! If you enjoyed it, feel free to share and like!