Nikon F5 Rechargeable Battery Holder with 18650 Cells - V2.0

This is a custom rechargeable battery solution for the Nikon F5 camera using 18650 lithium-ion cells. This is Version 2.0 - an upgraded design that improves upon earlier versions with better component integration and enhanced safety features.

The design replaces the original battery compartment with a 3S 18650 configuration and includes a Battery Management System (BMS) for safe charging and operation.

IMPORTANT SAFETY WARNINGS

READ CAREFULLY BEFORE BUILDING:

• I am not responsible for any damage to your camera, batteries, or personal injury
• Lithium-ion batteries can be dangerous if mishandled - risk of fire, explosion, or toxic fumes
• Always verify all connections before powering on
• Use only high-quality 18650 cells with built-in protection circuits when possible
• Never leave charging unattended
• Ensure proper ventilation during use and charging
• Stop use immediately if you notice any unusual heat, smell, or swelling

Components Required

Electronics:

• 3x 18650 Lithium-ion Cells - High-quality cells (Samsung, LG, Panasonic recommended)
• BMS 3S 20A: AliExpress Link - 3S Battery Management System
• 5.5x2.1mm DC Jack: AliExpress Link - For charging input
• Spot Welder: AliExpress Link - Recommended
• 18650 Terminals: AliExpress Link - 2 for series connections, 2 for endpoints
• Nickel Strips: AliExpress Link - For battery connections
• 22-24 AWG Wire - For internal connections and charging input
• Heat shrink tubing - Various sizes for insulation

Tools Required:

• Spot welder (essential for safe nickel strip connections)
• Soldering iron
• Solder
• Flux
• Wire strippers
• Heat gun or lighter (for heat shrink)
• Kapton tape
• Multimeter for testing

Assembly Instructions

Battery Pack Assembly:

1. Install 18650 cells in the battery holders (3S configuration: 11.1V nominal)
2. Connect batteries in series using nickel strips and spot welder
   • Connect positive of cell 1 to negative of cell 2
   • Connect positive of cell 2 to negative of cell 3
   • Remaining terminals are your pack positive and negative
3. Position the BMS on the left side of the battery pack
4. Secure everything with kapton tape

BMS Wiring:
Critical: Verify these connections with a multimeter before powering on!

BMS Connection Guide:

• B- (Battery Negative): Connect to battery pack negative terminal (0V point)
• B1: Connect to positive terminal of first cell (3.7V point)
• B2: Connect to positive terminal of second cell (7.4V point)
• B+ (Battery Positive): Connect to battery pack positive terminal (11.1V point)
• P- (Load Negative): Connect to output negative
• P+ (Load Positive): Connect to output positive

Output Connections:

1. Create connection pads using nickel strips formed in a full circle around the pads
2. Spot weld the circular connection for mechanical strength
3. Solder connection pads to the barrel - this serves as a central soldering point (I recommend to solder the wires to the connections pads before spot welding the pads)
   • Left pad (from top view): Positive (+)
   • Right pad (from top view): Negative (-)
4. Solder the BMS output wires directly to the barrel connection points
   • BMS P+ connects to left pad (positive)
   • BMS P- connects to right pad (negative)
5. Input and output share the same connection points (P- and P+)

Final Assembly:

• The completed assembly can be screwed to the original camera cover using the original 3 screws
• Ensure all connections are insulated and secure
• Test with multimeter before first use

Specifications

• Battery Configuration: 3S (3 cells in series)
• Nominal Voltage: 11.1V
• Charging Voltage: 12.6V (4.2V per cell)
• BMS Current Rating: 20A
• Recommended Charging Current: 2-3A maximum
• Charging Connector: 5.5x2.1mm DC jack

Usage Notes

• Always use the BMS - never bypass it
• Charge with appropriate 12V transformer (2-3A)
• Monitor first few charging cycles closely
• Store at partial charge (around 11.4V) for longevity
• Test repurposed cells before use to ensure they're matched and in good condition

Disclaimer
This is an advanced DIY project involving lithium-ion batteries and electrical modifications to camera equipment. Build and use at your own risk. I provide this design for educational purposes only and am not responsible for any damage, injury, or malfunction that may result from its construction or use.

Always prioritize safety and double-check all connections!

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If you build this project, please share your results and any improvements in the comments!