J1knd Battery Pinout Jun 2026

| Pin # | Pin Name | Description | | --- | --- | --- | | 1 | VBATT | Battery voltage output | | 2 | GND | Ground | | 3 | NTC | Negative temperature coefficient (thermistor) | | 4 | ID | Battery identification pin | | 5 | SCL | Serial clock pin (for communication) | | 6 | SDA | Serial data pin (for communication) | | 7 | Protect | Protection pin (for overcharge/discharge protection) |

| Pin Number | Wire Color | Function | Notes | | :--- | :--- | :--- | :--- | | 1 | Red (thick) | Cell 1+ (B+) | 12.6V max | | 2 | Brown (thin) | Balance Tap 1 | 4.2V (Cell 1 midpoint) | | 3 | Blue (thin) | Balance Tap 2 | 8.4V (Cell 2 midpoint) | | 4 | Black (thick) | Negative (B-) | Ground | | 5 | White (thin) | NTC Thermistor | Temperature sense | j1knd battery pinout

A thermistor (NTC) will read a specific resistance to ground. | Pin # | Pin Name | Description

Based on crowdsourced data from e-bike repair guides and battery management system (BMS) teardowns, here are the three most probable pinouts for a J1KND battery. Fix: The BMS thinks one cell group is at 4

When buying a replacement:

A failed balance pin (pin 2 or 3 in the 5-pin config). Fix: The BMS thinks one cell group is at 4.2V when it is actually at 3.6V. Measure directly on the battery cells inside the pack. If the white balance wire is broken internally, replace the wire or the BMS.