Kenwood TH-D74A 18650 Battery Caddy v3

This is a third iteration of a battery caddy for the TH-D74A. This one is easier than my previous two to print. This version, like V2, wraps a purchased battery holder. The printed battery holder from V1 should also work.

Update 2025-08-14: I remade the fully printable battery tray (similar but improved from V1). The battery terminals used are the Keystone 209 and 228. 
I also added a new version of the bottom clip with some tabs to try and secure it better.

Major Changes:

• Now in FreeCAD. Exporting to different formats and modifications should be more straightforward for folks.
• Improved geometry where the battery actually gets smaller (trapezoidal) as it moves away from the radio. This possibly contributed to a crack on my personal radio, near the curved plastic by where the clip attaches.
• Greatly simplified clip design. Now requires glue instead of a metal rod and a custom wound spring.
• Pinout and orientation key added to the insert tray piece, which should help alleviate wiring difficulties.

This is a larger redesign, as I ported everything over from OpenSCAD to FreeCAD. This should let other people work on it more readily, and made some of the complex geometry a lot easier (thanks to fillets and chamfers).

This version avoids the complex clip and spring mechanism. I found that thing constantly problematic, so I wanted to try and use a simpler design. Instead of a spring and pivot, this one relies on the compliance of the printed material, so you probably want to print the bottom clip piece in PETG instead of PLA if you can. I've included 2 versions of the clip, one solid and one with relief cuts. Super glue isn't great for holding the clip in place, but I'll keep experimenting. I may add some posts and slots between the main body and the clip to help hold it in place.

The specific battery trays I used are stamped as "Feiben 18650". These are designed to be PCB mounted, so I had to bend the pins under. Other compact trays may also work with a little modification. I also trimmed down some of the plastic near the belt clip on the radio for a better fit. For the actual contacts, I soldered some trimmed nickel battery welding strip material to the wires, and glued the strips down into the slots with super glue.