Quick hack – 18650 into a torch.

Greetings all

Quite some time ago, I bought a cheap set of torches/flashlights. Nice looking little aluminum LED units in a pack of 3. The problem with them is the stupid little 3xAAA power packs. AAA isn’t really known for longevity, and frankly the power is just terrible. Enter the 18650 cell so called for its dimensions, 18mmx65mm. Mine are from an old laptop that wouldn’t charge. Interesting, I found out that there is nothing wrong with ANY of the cells. They all still hold their charge and deliver very nicely. Its that damn pre-programmed failure BS they put in the charge controllers for laptops.

But, before I launch into another sermon on greedy corps, lets continue. So, I was hoping that the 18650 would just fit, but alas, things are never that easy. I found the 18650 to be about 16 mm longer than the original unit, but I was fairly sure that I could get it in there.

So here we go:

By figure:

  1. Basic disassembly, with 18650 for size comparison.
  2. 18650 in slot – not going to fit.
  3. LED section pulled and separated, rubber cap off rear push button
  4. All disassembled. all parts simply pushed out. How thoughtful of the designers.
  5. The buttons frame contact – I used this to attach the resistor.
  6. 1 ohm resistor soldered to button and pulled around so that it has a firm based to be pulled against when its re-inserted into the holder.
  7. button and resistor re-inserted.
  8. Solder on 4 ground connections to LED unit.
  9. LED unit inserted into metalised plastic front unit.
  10. Pushed back into main frame. This protrudes a little now as this will give the space for the 18650 cell.
  11. I had to print some shims as the cell doesn’t fit snugly, so I added a front cap for some protection.
  12. Shims glued into the frame
  13. All reassembled and light working. YAY.

So that’s it. Some new torches with oodles of power and they will last forever on a charge.


Adafruit MCP charger holder


I have been playing a little with some second-hand Li-ION cells from an old laptop in the form of 18650 cells. I have an Adafruit MCP 73833 charger that is LiPO/Li-ION capable in 3.7 and 4.2v with variable charge rate.

Nice little board but it is exposed to the world, and anyone who knows 18650s, knows they are frequently referred to as terrorist cells, they get nasty really quickly for no seeming reason. A short across the connector block, for instance, can very frequently result in much heat, fire and in some cases lots of sparks. Not so long ago, I managed to make the connection between  one of these cells and a set of LED’s using just my thumb, and it gave me a very detectable kick. Ferocious little animals indeed.

So a nice cover for the charger was in order. The box is friction fitted, has all the appropriate openings and even has pieces printed to make contact with the on-board LED’s. The print isn’t perfect so the contact isn’t great. The next version of the top should be better. STL’s can be found HERE.

Some more images below:

New LM8UU bearing holders for Prusa i3



So today I noticed during a print that the print bed on my Prusa i3 was wobbly, like a sea-lions bum wobbly. Not conducive to nice prints eh? I really wish they wouldn’t supply PLA parts for 3D printers. The stuff isn’t heat tolerant and just goes bad over time. Case in point is this:

Yeah, its broken. 2 out of 3 were, the third well on its way. It was also printed cheaply (ie thinly) and the texture was rough. So low cost eh?

Well they have now been replaced with

Got them from here. Thanks MartinMajewski, big help.

They went straight on, and its busy printing some more replacement parts for the printer. Think its time to rejuvenate the whole damn thing with some decently printed stuff.

Anyway, CAIO.