fischertechnik 14500 rechargeable battery box

thingiverse

**Warning: Use at your own risk.** LiIon batteries are potentially dangerous, if handled improperly. Do not use or charge unattended. Not safe for children. Use the protection cap to prevent short circuits. I needed a fischertechnik compatible small rechargeable battery box with more power than the conventional 9V rechargeable block batteries. As the 18650 type is too large, I chose two 14500 batteries, which allows for a small 30x20x60 mm form factor. Together they provide ca. 6.0-8.4 V which is sufficient for many ft applications. To be used with batteries *without* built-in protection, as a [HX-2S-01 protection shield](https://www.ebay.de/sch/i.html?_from=R40&_trksid=m570.l1313&_nkw=2S+5A+Li-ion+Lithium+Battery+Protection+Board+Pad+Module&_sacat=0) is included in the design to prevent overcharging and -discharging. Also, you'll need a piece of 0.8mm wire for the contacts and a couple of pin headers. Upon first use or after changing the batteries, the protection board needs to be initialized by providing a charging current to the P+/P- contacts (or the + / - contacts of the printed case). If the batteries are charged you can simply use the batteries' own current to do so, which is handy if you charge the batteries externally. See the images on how to shortcut from the board's P- to B-. If you're planning on making this box and anything is not clear from the pictures, please send me a message and I'll provide further information. Please consider leaving a "like" or posting your make as a token of appreciation for my work. Find my other fischertechnik designs [here](https://www.thingiverse.com/juh/designs). https://youtu.be/hU7KIjeh6Fw