Lithium Ion + USB Charge Upgrade for Hakko FX-901 Cordless Soldering Iron

This is a 3D-printed replacement battery holder for the Hakko FX-901 cordless soldering iron. There's space inside for a 2200 mAh cylindrical lithium ion battery and an Adafruit PowerBoost 500C Charger, allowing the iron to recharge with a USB microB cable. The original iron is unmodified; ONLY the battery holder is replaced.

Full instruction guide is on the Adafruit Learning System:
https://learn.adafruit.com/usb-rechargeable-cordless-soldering-iron