"Watertight" revolvable cap for Goobay Bike-Power 5.0

thingiverse

USE AT YOUR OWN RISK EDIT (24-Sep-2018): Due to a design flaw in the original cap design, I created a new one that doesn't feature a revolvable upper cap. Instead, it's designed for a permanent connection to the USB cable. This design is featured here as the single cap design. To use it, simply glue the USB cable into place on the cap and you're done. I've tested this design in a one-hour bike ride in heavy, pouring rain, and not a single drop made its way through, so I'm confident that, if printed and installed correctly, the cap will reliably keep water out of your power bank. IMPORTANT: Before clipping the two caps together, apply precision mechanics oil generously, or you won't be able to turn the upper cap!!! I bought the Goobay power bank, which is specifically designed for use on the bike but isn't watertight and shouldn't be used in the rain. This never made sense to me, so I designed this cap that fits snugly onto the power bank and makes it usable in wet and rainy conditions. It's composed of two parts that lock into one another. Once locked together, I've been unable to remove them from one another, so keep that in mind! The part is printed to fit the USB cable perfectly, which came with the power bank. Once clipped together and installed, the upper cap can be twisted to close the USB port. Due to the placement of the USB port on the power bank itself, it's not possible to design a rotating cap that closes perfectly. My design leaves a tiny gap through which water could possibly enter when no cable is plugged in and the upper cap turned. I currently can't rule out this possibility. When the cable is plugged in though, the parts fit together so perfectly that in my trials no water comes through. Maybe just keep it plugged in at all times! To charge the power bank, simply slide the whole assembled unit back off the power bank and charge as normal.