CryptaGlassV2 External Battery Pack

This is a short build guide for the Crypta Glass V2 External Battery Pack, which can give the glasses some extra juice when a larger battery is needed on the go, like for long video recording, or long driving journeys where Google Maps navigation is needed continuously for many hours.

This Instructables is meant to be quick and simple, so I won't go into deep detail.

Tools needed:

1. FDM 3D printer
2. Soldering iron
3. Soldering tools (solder sucker, wire strippers, etc)
4. Drill and 1.5mm bit
5. Small Phillips screwdriver
6. Needle nose pliers

Parts:

1. [1] Long M2 pan head screws (10-15mm long should be fine)
2. [2] 134N3P single USB power bank module
3. [3] 18650 battery
4. [4] 18650 case
5. Superglue
6. Glue tack
7. Paper bits
8. 22-24 AWG wire (really any wires thick enough will work fine)

Print settings (Cura Slicer):

1. Layer height >= 0.2mm
2. Supports - None
3. Speed - 50 to 100mm/s

I'm sure any settings will work, they're simple prints. I used PLA filament. For the clip, you can print 1-3, they're meant to be glued onto any side of the main case body, depending on which way you want to attach it to a belt, etc.

18650 case positive - power bank module B+

18650 case negative - power bank module B-

That's it, two solder joints, but be sure to measure and route the wires so they fit into the case well. Refer to the image below to get an idea of how things should be wired. Notice that the wires go under the battery holder and up to the powerbank module.

Here's how the electronics look inside the case. I've folded a piece of masking tape on itself and wrapped it around the battery to act as a pull tap, since I noticed it was hard to remove the battery after it has been pressed into the battery holder. Everything should just press-fit into the 3D printed case, but you can sand down the powerbank module's PCB board or battery holder if things are a bit too tight. Wedging small bits of paper between the powerbank module and the battery holder can help ensure there is no wiggle when plugging it in.

Then, simply screw on the lid and use superglue to attach the clips wherever you like on the case.