A 3D-printable 9V battery caddy compatible with Lego® Powered Up!® Hub 88009, so you can make your motorized Lego creations rechargeable instead of throwing away zillions of AAA batteries.
This is not a clone or duplicate of any Lego product or design. It is an entirely original design that replaces the 6xAAA battery holder in the Lego Powered Up hub with something more sensible. Read this description before you send a DMCA notice, ok?
You want the file
lego_powered_up_battery_box_v5.stl.
Print it with the base flat on the print bed. PLA should be fine, though I used PETG for mine. Print overhangs slowly.
See my related blog post for details.
The caddy is intended for use with 9V (PP3) form factor Li-ion USB-rechargeable battery packs. These packs are now widely available.
Unlike traditional NiMH batteries, these packs generally continue to deliver a steady 9V until their low-voltage cut-off trips and they shut off. So the hub won't complain about low batteries and refuse to work as soon as the battery is half discharged. They're convenient to recharge using a micro-USB cable. They (should) integrate all the annoying control circiutry for charge control, voltage buck/boost, overcharge protection, overcurrent protection, undervoltage protection, etc. And they're fairly cheap, wheras buying the ICs or modules to build your own is definitely not.
Enjoy. Let me know how you go.
If you're going to use the OpenSCAD sources, you'll need both my
lego_powered_up_battery_box_v5.stl and roman_hegglin's
uploads_f1_eb_f2_54_dd_Batteries.scad in the same directory.
Pull requests are welcome.
I used "Batteries in OpenSCAD" by Thingiverse user
roman_hegglin to supply a
convenient 9V model battery for preview and alignment purposes. I replaced my
own AAA battery model with his in the process.
Philo has done tons of great write-ups on Lego stuff. While I didn't use anything of his on this project, he was a great help in my ongoing efforts to design an easy to make custom Powered Up compatible cable, and my early success with driving standard hobby DC motors from the Powered Up hub.
There's an OpenSCAD design in here for a connector too. It isn't very accurate or printable yet, so ignore it.