4s 18650 Battery Pack, square, zip tie, battery contacts

thingiverse

This is an 18650 battery pack using leaf spring style battery contacts on the ends of the cells. This eliminates the need to solder or weld directly to the cells. Cells can be swapped out of the pack at a later date if they go bad or higher capacity cells become available. This version is square, to go on an FPV quadcopter. The weight of the finished pack is 235 gm. Here is a list of non-printed parts: Keystone 209 leaf spring contacts 8mm x 27mm copper strips (cut from a copper tray found at a thrift store) 22 gauge silicone insulated wire 14 gauge silicone insulated wire XT60 battery plug 4S battery balancing plug 5" zip ties from Harbor Freight M2 nuts M2x12mm button head cap screws A drinking straw. 3 copper strips are needed to connect pairs of contacts. The contacts are slipped onto the strip, test fitted into the 3D printed ends, then soldered to the strips. Balance plug wires are attached and the contacts are hot glued into the ends to hold them in place for assembly. Once assembled, the glue doesn't really do anything. Be careful when swapping out the lids. When loosening the M2 screws, pull the lid away from the pack while unscrewing both screws evenly to prevent the nuts from backing out of their holes inside the pack. If the nut comes loose, you'll need to open up the pack to fix it.