Makita compatible battery, Size of BL1820 4.2Ah, 45Amps, engineered for high power output using 21700's

thingiverse

09/15/2023 2319: I modified all the plastic parts increasing the widths slightly where i could , to make them easier to print and produce stronger parts as well as some things fit better now. But It is still tricky to get battery walls this thin and still strong took me a couple yrs to figure this out a solution. . The manufacture info is outdated, so ignore it: I had to dehydrate the Priline super hard PC-CF 12-16hrs, then I had to increase the flow 101-102.5% to make up for the volume lost during dehydration 238C hotend is the hotest I could go , 65-70C bed is the hotest, 25mm/sec is fastest you can print, no fan, minimum 30 sec dry time between layers with enable lift , nanopolymer on bed 9/14/2023: Added the TPE Gasket if desired, that provides seal between top and bottom half of battery case against dust and water, also can be thickened as needed to compensate for any warping etc.. eSun TPE 83-A Black, I got this especially because for some reason it seems to tolerate heat very well, so far better heat tolerance than PETG 8/31/2022: Just uploaded correct version of battery button stl and step file, (previous version had no hole for the spring) also deleted redundant step files. Shapr3D did not have parametric history at the time i made this, so I had to use a lot of "bandaids" seen on the step files. I built this around Molicel's 21700 P42A Batteries, 18V 4.2AH 45Amps. This build must have 21700 dimension less than or equal to diameter 21.25mm any thing larger wont work, This battery fits in every Makita tool as well as other brands using adapter. I tested in over 50 tools, works with Makita's rapid charger and generic chargers. Almost same dimensions as Makita 18650 5S battery, compared to Makita's BL1820 the difference is negligible, this battery is only 2mm wide and taller, 4mm longer, and 100gm heavier. I welded .15 stainless steel to the .25 copper tabs, then electroplated with nickel. I maintain Cu 3.125mm2 - 4mm2 = 12-14AWG. The positive and negative stand off tabs needs to be folded in thirds, (3mm width x.25mm copper x 3 folds =2.35mm2 ) the solder will flow down through the PCB (bms) forming a good structural and low resistance connection to battery I use .2 -.25mm x 20mm double sided thermal conductive tape over (leave the backing on the side thats in contact the battery case, one length over each side of 5 cells over the spot welded copper strips. this allows the pack to be inserted into the case without catching the edge of the metal strips and it also helps balance the heat between ends of cells, and facilitate the loss the conduction of heat by the case. when comfortable you can then remove the blue blacking to let the heat conductive tape transfer the heat through the battery case and into the environment CNC details: I expanded the sketch outline by 0.75mm in Shapr3D then used a 1.5mm or 1/16th" end mill bit and selected cut on the line. Both copper and stainless steel came out with exact dimensions. Using unmodified 3018 pro (120$ Amazon open box) original 75w spindle, I posted both modified and unmodified copper and steel sketches Laser Details: Used 3018 with a 2.5w output laser 100% at 270mm/min, cuts through fish paper while leaving white adhesive backing intact, Laser cost 30$ from ali express.