The full size version of the teardown video including dremeling the case open and more discussion about the construction. These batteries use a lithium cell and buck converter to give out a steady 1.5V for most of their discharge, dropping deliberately to around 1V at the end to trigger battery warning systems. They are the equivalent to a 2000mAh rechargeable AA cell and can supply up to 2A, although they do get hot at high current and may cut in and out thermally. They seem to charge at 5V via the same contacts. If you enjoy these videos you can help support the channel with a dollar for coffee, cookies and random gadgets for disassembly at:- http://www.bigclive.com/coffee.htm This also keeps the channel independent of YouTube's advertising algorithms allowing it to be a bit more dangerous and naughty. ... https://www.youtube.com/watch?v=dakm4ra8Xv0

This project turned out even better than expected. It was inspired by the lights used in pinball machine playfields, where coloured inserts are illuminated from behind. I've attached two scripts at the bottom of this description. If copied and pasted into openscad they can be used to create custom versions with the following adjustable variables:- Outer diameter of the insert (all measurements in millimetres) Depth of main disk thickness of front layer of plastic. Thicker = stronger/diffused and allows sanding flush diameter of LED length of the LED support measured from the front There are two versions:- Star, which has eight radial lines and is the strongest version. Concentric, which has a series of fresnel style lenses to spread the light. I recommend printing these in transparent/natural PLA to allow maximum light transmission. I've not tried coloured transparent PLA yet. They print very fast with a small amount of filament. For example 20mm=1g, 25mm=1.5g, 30mm=2g, 40mm=3g, 50mm=4g, 75mm=7.5g. You can fit a standard LED with suitable resistor like 150 ohm for powering lots of these in parallel from a standard USB power supply. Self colour changing LEDs look good, as do self flashing ones. You could size the LED holder to take an addressable LED string pixel. You could also animate the light in the style of a pinball feature effect. Diffused LEDs are best to get a softer spread of light through the insert. For drilling the holes, a plunge drill or router will give a clean vertical hole to a repeatable depth. If you enjoy these videos you can help support the channel with a dollar for coffee, cookies and random gadgets for disassembly at:- http://www.bigclive.com/coffee.htm This also keeps the channel independent of YouTube's advertising algorithms allowing it to be a bit more dangerous and naughty. #ElectronicsCreators The openscad scripts are below. You can copy and paste the selected script into openscad, and adjust the variables at the top to fine tune sizing to your requirements before making into an STL file. Here's the star script:- //Pinball style star LED insert $fn=100; //You can adjust the variables below size=25; //diameter of insert in mm depth=5; //depth of insert face=1; //thickness of front face led=5.2; //diameter of LED stem=15; //length of LED stem //don't adjust anything below here difference(){ union(){ difference(){ union(){ //main disk cylinder(h=depth, d=size); } //internal cylinder translate([0,0,face]) cylinder(h=depth,d=size-2); } //star fins for (i=[0:36:350])rotate([0, 0, i]){ translate([0,-.5,face]) cube([(size/2)-1,1,depth-face]); } //LED pillar cylinder(h=stem,d=led+2); } //led hole translate([0,0,face]) cylinder(h=stem+1,d=led); } And here's th ... https://www.youtube.com/watch?v=SyjoILhsWBg