This is a parametric box design for a Minty Boost V3 USB Mobile Charger. The recommended Altoids Mints Tin and other boxes had a few issues for my purpose.I wanted something that could:Fit 3 batteries instead of 2 (for a longer charge)LED to signal if it's on or offNote the LED has a built in flashing circuit that doesn't need a current limiting resistor. The reason for this is to save current over a regular non-flashing LED and to save component space as well as draw attention to it being on.Minty Boost V3: http://www.ladyada.net/make/mintyboost/This project also uses OpenScad Font: http://www.thingiverse.com/thing:6820 for a text warning on the bottom of the minty boost and the title on the top.WARNING: Use this at your own risk. Batteries and MintyBoost get very hot as documented on Adafruits website, particularly with high current devices like the iPhone etc. Batteries are generally designed to safety vent and internal resistance generally increases when they get hot. However there is a remote possibility of a battery exploding or the case melting if the batteries gets too hot. It's a good an idea to keep the cover off the case when charging and if the batteries get too hot, interrupt your charging for a while to allow the batteries to cool.Print out the top and bottom (I used 25% fill)Clip the blue sheathing off the terminalsClip the crimp off 1 of the terminals (this will be for the positive lead) and solder to attach wireOpen up the end of 2 springs and crimp to 2 terminalsWire everything up, the positive lead goes along the battery channel and is soldered to the terminalNegative gets soldered to the bottom of the spare springSwitch is wired into the negative led, led is wired between positive and negative after the switchLay out the batteries, springs and adjust fit