Electric scooter || bird 3 || step by step || DIY || tutorial || brushless DC controller
Summary
This video details the process of converting a Bird 3 scooter by installing a 36-volt, 350-watt, 18-amp controller and a 36V to 12V step-down converter, sourced affordably from Amazon. The tutorial covers disassembling the scooter, identifying and reconnecting necessary wires for the throttle and headlight, bypassing the battery's BMS, and integrating new components like a loop key and illuminated buttons. It emphasizes careful wiring, heat shrinking, and ensuring all connections are secure for optimal performance.
Key Insights
Affordable conversion components are readily available.
The video highlights that essential conversion components, such as a 36V 350W 18A controller and a 36V to 12V step-down converter, can be purchased very cheaply on Amazon, making budget-friendly scooter upgrades accessible.
Key components require careful wiring and identification.
Successful conversion relies on correctly identifying and wiring crucial components like the throttle wires (red for positive, black for negative, yellow for signal), motor phase wires (color-to-color connection), and integrating the 12V output from the step-down converter for accessories like headlights and taillights.
A BMS bypass is crucial for battery functionality.
To ensure the battery works properly after conversion, a BMS (Battery Management System) bypass is necessary. This involves bridging the B+ terminal directly to the P+ terminal, which allows the battery to provide power, unlike the zero or minimal voltage it might output without this bypass.
Integrating a loop key or ignition switch enhances control.
A loop key or ignition switch can be wired into the main power lead (positive and negative) to act as a kill switch for the scooter. This ensures all power is completely cut off when the key is removed, preventing accessories like lights from remaining on unintentionally.
Sections
Initial Disassembly and Component Identification
Accessing internal components involves removing the top cover.
The process begins by removing the top cover of the scooter's handlebar column to access the internal wiring and components. This area previously housed a GPS module, which needs to be removed.
Disconnecting and clipping unnecessary wires is essential.
The main wire harness needs to be disconnected, and non-essential connectors, like those for the brake lever sensor (yellow and green, and a three-wire connector), should be clipped. These clipped connectors can be repurposed for the throttle and headlight.
Isolating and preparing the throttle wires.
To access the throttle, the front and right brake levers and their rubber grips must be removed carefully. After releasing the brake cable, the entire assembly can be pulled out. The brake lever's connector is clipped off as it’s not needed. Focusing on the wires leading to the throttle, identified as yellow, red, black, and blue, the excess wires are clipped off, leaving only the necessary three: red (positive), black (negative), and yellow (signal).
Removing the battery pack housing.
The scooter needs to be flipped upside down to access the battery pack. This involves removing seven 7-point security screws (using a T25 bit) from the bottom cover, followed by four T25 screws in the front cover. The back cover is then lifted after releasing connected tabs.
Accessing and disassembling the original controller.
After removing the back cover, the battery is lifted out. The original controller board is accessed by removing four Phillips screws. The motor's male connector is clipped to retain it, along with an XT60 female connector. The board itself is carefully broken away from the connector using pliers and vice grips to salvage the XT60 connector.
Battery Pack Preparation and Modifications
Preparing the battery for BMS bypass.
The white putty surrounding the battery terminals is removed using a razor blade. This is done on both ends of the battery pack for easier access and potential future removal.
Executing the BMS bypass.
The BMS bypass involves bridging the B+ terminal directly to the P+ terminal. This is crucial for enabling the battery to function and output power, as without it, the voltage might read zero or very low.
Reinstalling the modified battery.
The modified battery pack is slid back into its housing. The orientation of the battery might need to be flipped to fit correctly within the frame, particularly near the kickstand area. Ensuring the battery fits snugly without pinching wires is important before proceeding.
Controller and Step-Down Converter Installation
Positioning the new controller and converter.
The new controller and the 36V to 12V step-down converter are placed within the scooter's frame, typically near the battery housing. Their placement should ensure they fit securely without obstructing the closing of the covers.
Installing buttons for lights.
Two 12mm buttons are installed for the headlight and taillight. Holes are drilled in the appropriate locations on the scooter body to mount these buttons securely.
Wiring the Headlight and Components
Creating a 12V supply for the headlight using resistors.
Since the headlight requires 12 volts, two 30-ohm resistors are wired in parallel to achieve this. Solder is used to join the resistors and connect them to the white lead of the headlight wiring. The opposite end requires a new connector.
Connecting headlight wires to the button and green wire.
The white wire from the headlight is connected to the green wire of the scooter's harness. The new connector for the headlight is attached to the resistors. The button is wired to these prongs. Extensions are added to the green and white wires if they don't reach the button.
Wiring the throttle connections.
The throttle wires are connected as follows: black to black, red to red, and blue to yellow. This specific configuration is determined through testing with alligator clips and confirming the wheel spins in the correct direction when throttle is applied.
Activating cruise control.
Cruise control is activated by holding the throttle steady for about 10 seconds. Tapping the throttle disengages it. An extra white wire in the throttle connector is not used and should be clipped and heat-shrunk for safety.
Configuring the three-speed switch.
To set the motor to high speed, the black wire (ground) is connected to the blue wire (high speed) by soldering them together. Alligator clips are used initially for testing. The location for a new connection point (like an XT90 connector for power indication) is drilled.
Preparing wire routing for the battery housing.
Cable extensions are soldered onto necessary wires. The XT90 connector's male part is prepared to indicate power status. Motor wires, hall sensor wires, and loop key wires are routed through a small hole in the frame after trimming the rubber seal to accommodate them.
Wiring the taillight correctly.
The taillight cable connects to the rear light. Attention must be paid to the polarity: black wire is negative, and red wire is positive. This connection is made through a switch, with one side of the broken wire connected to one terminal of the switch and the other side to the other terminal.
Integrating the Loop Key and Step-Down Converter
Connecting the loop key for power control.
The loop key is wired into the main power system. One wire from the loop key connects to the positive side of the main power lead (red wire), and the other connects to the negative side (black wire), effectively acting as a kill switch when removed.
Wiring the step-down converter for 12V output.
The step-down converter has four wires: black and red for main power input (connected to the battery's positive and negative), yellow for 12V positive output, and blue for 12V negative output. These output wires power the headlight and taillight.
Correcting initial wiring errors for accessory power.
An initial mistake is made where the step-down converter's positive output is connected directly to the main power line, causing the lights to stay on continuously. This is corrected by rerouting the red wire from the step-down converter's output to the key ignition switch's input, ensuring lights only turn on when the key is inserted.
Connecting headlight and taillight to 12V output.
The positive terminals of the headlight and taillight (black wire for headlight, yellow for taillight, both positive) are connected together, as are the negative terminals (red wire for headlight, red for taillight, both negative). These combined positive and negative leads are then connected to the 12V output (yellow and blue wires) of the step-down converter.
Final Assembly and Testing
Connecting the charging port.
The charging port cable is connected to the battery pack, ensuring all wires are properly managed and not pinched.
Securing the battery housing.
Cloth tape or Gorilla Tape is used to protect wires from being pinched in tight spots as the front cover is reassembled. The battery housing screws, including the 7-point security screws, are reinstalled to secure the cover.
Verification of functionality.
The scooter is tested to ensure the controller, throttle, lights, loop key ignition, and charging port function correctly. The video concludes by encouraging viewers to check the description for links to parts and tools, and to like, comment, or join the Discord community for support.
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