Battery holder for integrated LED seatpost (Brompton)

thingiverse

My ongoing Quest to perfect my Bromton bike. I needed a seatpost about 60-75mm Longer than the Longest I could find, I wasnt happy with the telescopic Brompton post (although it was long enough) it kept slipping and I never knew which part was slipping, Its unessecary weight and its a unessecarily complicated solution. SOOOOO .... I made my own seatpost :P naturally . and I figured whilst I was at it I might as well Include some LED's as per Lightskins seatposts which I think are awesome but I dont think are availible for a brompton and certainly not at the legnth I need. I ordered some thick walled aluminium tube of the correct size 31.8mm and Tranfered the correct size holes and cutouts to accept the old seat mounting hardware. I drilled some holes for the switch and LED's at approximatly the right angle to shine in drivers direction. I then used it for a few days to check that nothing would fail. Satisfied that nothing was going to snap and send a sharp seatpost into my buttcheeks I started on integrating it all. I epoxied some LED's in Place and wired everything up At this point I intended to simply buy a 2xAA holder and stuff it into the bottom of the seatpost with some padding to keep it in place. BUUUUUT I have a 3D printer so I figured I could do better. Hence the Rabbit hole opened up before me. I figured if I was making a battery holder I should make it secure in there properly , Then I also figured If I made it the exact size of the seattube below the Plastic collar it would also add a bit more support to the seatpost AND allow me to use a saddle height insert which Ive never used before and seems like a good idea. So even more swearing and many many many hours on freecad and Ive ended up with the part availible for download. It Holds 2 x AAA batteries secure in the bottom of the seatpost AND Acts as additional support for the bottom of the seatpost inside the seattube AND acts as a stop when the correct height is reached. Its not perfect I don't doubt that, but as a Free 3d printable solution to half of making a lightskin seatpost Im happy. Parts I used :- https://www.ebay.co.uk/itm/192652347100?var=492793905846 Aluminium Tube 1 1/4 x 10SWG https://www.ebay.co.uk/itm/133766954551?var=433210785725 Switch The 5mm LED's and resistor are just standard Items availible anywhere. I think the resistor is 47Ohms I got the value from a online calculator. I can't provide a link for the seat post I stole the hardware from as it was an old one I had in stock but it was this style https://www.ebay.co.uk/itm/UK-Litepro-Alloy-Silver-580mm-Extended-Seatpost-Clamp-Superlight-340g-Brompton/304161825766?hash=item46d17523e6:g:viwAAOSwFgNhUKlc&pageci=22304646-98d8-49f4-acc5-6eb63fae0a9d&redirect=mobile I borrowed the battery contacts form a broken childs toy which I seem to have thousands of. Obviously this is quite a involved project involving more than Simply 3D printing and not an insignificant risk. You take your buttcheeks safety into your own hands and I will not be held responsible. However with this part, some files , a drillpress (you may even be able to do it with a handdrill) , soldering Iron and some patience anyone can make their own brompton Intergrated LED seatpost. Unfortunatly electronics are not my strong point so it only has the two settings on AND off , I would have loved to include flashing and or strobing but wasnt able to find a board which would fit inside the post that I could use to accomplish this and definatly dont have the knowhow to attempt it myself. If you manage it I would love to see. Would probably be a nightmare anywaysince the LED's would need to indivdually wired and there aint a lot of room in there. This is not intended as a how to as such. Also I most definitely won't be offering these for sale , it's not worth the risk of getting sued either by lightskins or the end user when one breaks. UPDATE 14/12/2021 New version uploaded, Its longer so the batteries and connectors have more room Ive also added holes on the top for the wires to come through and deepened the Hex hole so it can be printed at a angle. I ended up printing this in ABS simply because I ran out of PETG , But PETG was working just fine for the prototypes.