4s 18650 Battery Pack, "flat" for pocket or belt, 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 "flat" (actually slightly curved) to go in a pocket, clip on a belt, or clip on a FPV goggle band. I designed it specifically to power my DJI FPV goggles. 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 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. To open up the pack once assembled, use an xacto knife to cut the catch off the zip tie nub. The nubs will pop free and you can open up the pack. A "de-catched" nub slipped over the zip tie tail is a useful tool to help tighten the 4 zip ties. Be careful when swapping out the caps. When loosening the M2 screws, pull the cap 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.