Enter: The Frame
This is GoPro's answer to this problem. Now you can shoot while being connected to an external power source. But, wait, $40 for a piece of flimsy plastic (to be fair, TWO pieces of plastic!) with a few holes in the side? No Thanks.
I really wanted this capability, but didn't want to spend a lot of money or sacrifice the poly case by drilling a hole in the side.
Enter: Modify a Mini-B USB Cable to Power an Enclosed GoPro Hero3 (With Skeleton Back Door) (This Instructable)
Disclaimer: Perform this at your own risk, I take no responsibility for your actions and assume you have some competency. With that being said, this instructable is merely a cable modification, I do not modify the camera or case.
Step 1: Parts/Tools
-A Mini-B USB cable of your desired length. I found an old 3-footer in my spare cables tub. I might suggest not using the one included with your GoPro (just in case...). Note: I have a Hero3 Black Edition which uses a Mini-B. I do not know what the Hero2 (or whatever) uses. Also, of course, your cable design may be slightly different.
-Glue...? I used some, it may not be needed though...
-Wire Strippers/Cutters. Not that you will be stripping wires explicitly - but you will need to cut off the black plastic molding around the connector and trim back the cable sheath.
-Long Nose Pliers. For general dismantlement and metal bendage.
-Small Rotary Cutting Tool. I use a really cheap one from Harbor Freight. Yes, it is cheaply made and doesn't have a lot of power, but hey its like $10 on sale.
Step 2: Destruction.
-Disassemble the metal casing. For my cable, I bent away the strain relief tabs and then separated the main casing. Sorry, I do not have a better photo of this step!
Step 3: Modification.
-Glue the plastic tab back onto the connector. It doesn't have to be a super glue job, as long as it stays attached, it is not exactly a structural part of the connector. Note: try not to get glue on the power pins (outer, black & red).
-Use your rotary cutter to cut down the side walls of the main connector body as well as a horizontal cut on top of the connector. Bend it down into about the same angle as your pins to form the new body of the connector. Also bend and flare the newly created tabs out (see photo).
Step 4: Test.
-Bend the newly created tabs against the connector and make sure they hold it down.
-Plug it into your GoPro Hero3 and make sure it powers it. You may have to adjust the position of your pins slightly, or scrape off some glue from the top of them.
-Look for any adjustments you need to make. The metal tail of my connector body was too long, it needed to be cut off.
Step 5: Adjustments.
-Add some more glue to seal the deal.
-I also trimmed off more cable sheath, you may or may not need to.
Step 6: Record.
I have not done any long term testing with mine yet, but it is definitely nice to know that I have the option, if I need it!
Let me know if you have questions! Thanks!