I can't stop thinking about GoPro accessories ever since I wasn't able to find one I wanted for less than $40.
This is a 2 part, 3D printed battery holder. All you need to make it is access to a 3D printer and the stl file below. The reason I wanted to make it is so I won't have to empty the pocket of my accessories pack's every time I need a fresh battery. The box will hold 4 GoPro batteries, 2 G4 FeiuTech-tech stabilizer batteries and even has room between the hinges for 3 Micro SD cards. It's also the same width as a Wasobi power back shipping case so one can be glued piggy-back onto it so in total, 7 batteries and 3 mini SD cards can all be packaged together. The whole thing slips into the pocket they were tossed in before.
Oh, an additional feature is, fresh GoPro batteries' tabs stick out when the case is closed so I can see how many batteries I have left before I have to convert to the Wasabi just by looking at it.
Step 1: Feature Details
As I stated, the primary reason for this experiment was to come up with a way to keep my growing collection of camera batteries in one place. And as long as I was doing that, I thought it might as well hold the used ones too. To accomplish that, I formed the sides of the box to catch the GoPros batteries' release tabs as it closed on them. This bends the tabs outward, making them protrude from the side of the box as it closes. This is the box's normal behavior when the batteries are inserted right side up. Replacing spent batteries back into their slot upside down, the tabs are kept inside. Now, looking at the box open or closed, I can immediately see how many good batteries I have left simply by counting battery tops (open) or tabs (closed).
My G4 is new and I haven't seen how long it's batteries last. Hopefully longer than the G3's did. But since the G4 came with a spare set of rechargeables, that might suggest an answer for that. The spares fit into the box as well, so at the expense of an additional camera battery slot, I added spaces for the G4s.
Then, there was room left over for something small between the hinges. As I had no batteries that would fit the space, I drew in three slots for mini SDs. I drop things a lot, so I made them a tight fit. I printed up several test-size slots and went with the best one for my printer. My printer used to be a Makerbot, but since every bit of plastic has been replaced with billet aluminum, the case re-done for vibration-free operation and the bed, the Makerbot's only aluminum part, changed to glass, I don't think it's a Makerbot anymore. It certainly doesn't print like one, so I can't predict what size slots your printer will produce.
My slots allow the cards to be inserted up to their notch before they hit bottom, and the cards are pressure fit tight enough so a finger and thumb are required to remove them. That's my safety feature. Play around with the slot size and make them fit similar to mine... Because crawling around through the grass on your hands and knees, trying to find a mini CD just isn't dignified.
Step 2: Accessories
I also have a Wasabi battery back for my camera. Because the camera has a screen and the battery doesn't, it's only to be used when nothing else is available and I still need pictures. So far, I've never had to use it, but it lives in the same pocket as the others, so I made the box the same width as the shipping package the Wasobi came in. It's plastic, protects the battery, locks it in place and after I cut a notch in one end, it can be charged without removing it. This is also why the corners of the box aren't rounded. After I glued the Wasobi case in place, I rounded all the edges together, so they'd match. If you aren't planning on adding a Wasabi battery back or you're not as retentive as I am, you can round the box's edges at the same time you adjust the slot sizes.
Step 3: Fit
My battery box was designed for my equipment and camera case. It's more likely than not, your situation is different. My box, with it's attachment fits perfectly into the pocket of the pack it was designed for. The cables that used to share that space will have to find a new home though. I haven't used this in real life yet, but I'm looking forward to seeing how close I've gotten to battery management nirvana. I've tried to think of everything, but until it gets field use, all bets are off.
If you make this, have better ideas or think of a better way, please write about it in the comments... Until then, I'm off to make a stake that can actually be pounded into the ground without breaking tabs off.
I tell ya, I just can't get my mind off this GoPro subject.