bac-hardware/eps/battery-contact/18650-2s2p/README.md

# EPS Battery Contact PCB – 18650 2s2p

**Subsystem**: EPS  
**Status**: ✅ Released  

**Latest Release**:  
- **Version**: v1r2  
- **Date**: 2025-04-03  
- **KiCad**: v9

## Overview
This board contacts four 18650 lithium-ion cells in a 2s2p configuration. It connects to the EPS board from underneath using pins soldered into plated slots. A V-cut allows the board to snap apart, yielding one section for the Ym end and one for the Yp end of the pack.

It is mechanically constrained by inserts inside the EPS bay and is designed for ground-based and high-altitude balloon testing—not for spaceflight.

## Specifications
- **Dimensions**: 68.7 mm × 33.75 mm (single)  
- **Layer Count**: 2  
- **Panelization**: Yes  
  - **Panel File**: Included in release  
  - **Boards per Panel**: 4  
- **Mounting**: Pressed into EPS bay on battery pack ends  
- **Stacking**: Not applicable  

## Files
- **Design files**: Located in the `kicad9/` folder  
- **Schematics**: [PDF](https://codeberg.org/buildacubesat-project/bac-hardware/releases/download/eps-battery-contact-18650-2s2p-v1r2/bac-eps-battery-contact-18650-2s2p-v1r2-schematic.pdf)  
- **3D Render**:  
  ![3D Render](https://codeberg.org/buildacubesat-project/bac-hardware/releases/download/eps-battery-contact-18650-2s2p-v1r2/bac-eps-battery-contact-18650-2s2p-v1r2.webp)

## Manufacturing
- **Release**: [eps-battery-contact-18650-2s2p-v1r2](https://codeberg.org/buildacubesat-project/bac-hardware/releases/tag/eps-battery-contact-18650-2s2p-v1r2)  
- **BOM**: Included  
- **Instruction**:  
  - **Ordering**: Included (PCBWay)  
  - **Sourcing**: Not Included  
  - **Assembly**: Not Included  

## Notes
Recommended cell type: LG MJ1.  
For experimental and prototyping use only.

## License
[CC BY-SA 4.0](../../../LICENSE)