The control pin is the gatekeeper. It is used by the charger to manage the charging process and by the battery’s internal BMS (Battery Management System) to enable or disable the pack if a fault is detected, such as a short circuit or over‑current condition.
When holding the battery with the terminals facing you, the pinout generally follows this configuration:
This pin helps the tool or charger identify the battery type or capacity, ensuring the correct power profile is used. hart 20v battery pinout diagram better
If a battery will not be used for several months, it is generally recommended to store it at approximately 40% to 50% charge rather than fully depleted or fully charged.
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 ) The control pin is the gatekeeper
Understanding the Hart 20V Battery Pinout When working on DIY projects or troubleshooting power tools, understanding the battery pinout is essential. The system typically uses a 5-pin interface to manage power delivery, safety monitoring, and balanced charging. Pinout Configuration & Functions
This table synthesizes information from multiple hands-on sources to give you the most comprehensive pinout available. If a battery will not be used for
Lithium-ion batteries are not toys. A "better" diagram is useless if you burn your house down.
Use a multimeter to confirm the voltage between + and - before connecting your project to ensure the polarity is correct.