Ford CMAX 21-Cell Busbar Kit Installation Guide
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Convert your OEM 25Ah hybrid module into a 4S5P high-current 14.8V battery — built for serious power applications like car audio systems.
Overview
This busbar kit allows you to reconfigure a Ford CMAX / Fusion 21-cell module into a powerful, compact battery without opening or modifying the cells.
- Final configuration: 4S5P (14.8V nominal)
- Output capability: Up to 1500A (22,000+ watts)
- Designed for clean, reliable, high-current builds
Note: Battery module is NOT included.
View Product⚠️ Safety First
- This system can deliver extreme current (1500A+)
- Always use insulated tools
- Remove rings, watches, and metal jewelry
- Wear safety glasses
- Verify voltage before starting
Step 1 — Prepare Your Workspace
Start with a clean, stable work area.
Identify your components:
- Busbars (metal plates)
- Custom PCB
- M8 nuts and washers
- Wiring harness
- Heltec balancer (Pro kit only)
Place the battery module on a flat surface with terminals facing up.
Step 2 — Install the Busbars
- Lay the busbars directly onto the factory terminal studs
- They are pre-designed to create the correct 4S5P layout
- Make sure each busbar sits flat and flush
- No debris or gaps between contact points
Output Terminals:
- Standard Kit: 3 terminals
- Pro Kit: 6 terminals (better current handling)
Step 3 — Install PCB & Balancer
- Place the PCB over the studs (on top of the busbars)
- Align all holes carefully
- Secure using washers and M8 nuts
If using the Pro Kit:
- Mount the Heltec balancer
- Connect it to the PCB header
- It will begin balancing automatically
Important: Tighten firmly, but do NOT over-tighten.
Step 4 — Wiring Connections
- Connect the wiring harness to the PCB
- Attach main positive (+) and negative (–) cables
- Use high-quality ring terminals
Final check:
- No loose hardware
- No tools left on module
- Busbars not touching metal casing
Step 5 — Power-Up & Testing
- Check voltage with a multimeter
- Expected range: 12.0V – 16.8V
- Confirm balancer LEDs (Pro Kit)
BMS Setup:
- Configure for 4S Li-ion
- Max voltage: 4.2V per cell
Pro Tips (Car Audio Builds)
- Use oversized OFC cable for maximum current flow
- Keep wire runs short
- Ensure strong, clean grounding
- Monitor heat under heavy load
Built for high-performance lithium systems • JAG35