The email subject line was blunt, devoid of any corporate pleasantries:
Finally, a better pinout diagram fosters . The “second life” of power tool batteries is a growing movement. DIYers use old Hart battery packs to power soldering stations, portable speakers, RC cars, or emergency lighting. However, simply hooking a motor to the B+ and B- terminals bypasses the BMS’s low-voltage cutoff, leading to destroyed cells. A better pinout diagram shows the enterprising maker exactly how to interface with the BMS. It might illustrate a simple circuit using the ID pin to request power or explain how to simulate the tool’s “enable” signal. This turns a discarded Hart battery from waste into a sophisticated, rechargeable power station for any project.
Attached was a grainy, scanned PDF.
If the goal is to identify terminals (B+, B-, C, T, ID), Hart batteries typically follow a common Chinese BMS pinout used by many budget 20V Max tools. However, “better” implies a known flaw in existing diagrams — but no flaw is specified. Without knowing the issue (wrong voltage readings, missing thermistor pin, incorrect cell order), no diagram can be “better.”
Six cells. The Hart battery was a 5-cell stack. hart 20v battery pinout diagram better
Here is the typical layout from left to right (facing the terminals): 1. Positive ( ) - Terminal 1 Main positive power delivery ( actual average). Usage: Sends power to the tool. 2. Communication / Thermistor ( ) - Terminal 2 Function: Usually designated for thermal protection.
Serves as the main negative DC return track for the power circuit. Deep Dive into Terminal Functions 1. Main Power Terminals ( B+ and B- ) The email subject line was blunt, devoid of
Interfacing with power tool batteries requires caution. Shorting the positive and negative terminals can cause rapid discharge, sparking, melting plastic, or catastrophic battery failure. Always use a digital multimeter to verify your specific battery's layout before connecting external loads or custom adapters.
The leftmost and rightmost slots are the heavy-duty terminals responsible for high-current discharge. A fully charged pack registers approximately , dropping down to a nominal 18V under continuous operational workloads. These two pins are the targets when wiring Hart DIY battery adapters to run external electronics like custom robotics projects, 12V-24V camping arrays, or power wheels conversions. 2. The Temperature Pin ( TH / T ) However, simply hooking a motor to the B+