Hart 20v Battery Pinout Diagram Better Jun 2026

Disclaimer: Modifying batteries can be dangerous. Always work with caution and follow safety guidelines when handling lithium-ion batteries. Share public link

The is an essential technical roadmap for DIY electronics enthusiasts, 3D-printing makers, and tool repair technicians looking to tap into or diagnose Walmart’s signature white cordless tool battery line. Manufactured by TTI (Techtronic Industries)—the same powerhouse behind Milwaukee and Ryobi—HART 20V lithium-ion battery packs feature a specific blade-terminal interface designed to deliver robust power while ensuring complex safety handshakes between the pack, the charger, and the tool.

Your diagram is wrong. The thermistor bridge is a lie. This one is better. Fix it or people get hurt. hart 20v battery pinout diagram better

The HART charger communicates via SMBus (System Management Bus). If you try to use a generic Li-Ion charger (like an iMax B6) directly on B+ and B-, the battery will reject the charge. Connect your charger leads to B+ and B-, but also connect a 10k NTC thermistor between T and B- to simulate room temperature. Without this, the BMS assumes the battery is on fire (infinite resistance) and cuts the circuit.

Over time, oxidation can occur. Use a small wire brush or emery cloth to clean the terminals to ensure a solid connection. Disclaimer: Modifying batteries can be dangerous

Based on measured voltages and technical teardowns, the five pins are identified as follows: Positive (+) : The main voltage output terminal (approx. 20V). TH (Thermistor)

A data/identification pin used by the charger to recognize the battery type and capacity. This one is better

A temperature monitoring pin connected to a 10kOhm thermistor. It signals the tool or charger if the battery is too hot or cold to operate or charge safely. ID (Identity):

: Interior pin. Communicates battery status or capacity to the tool and charger.

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Connect a jumper wire from the terminal of the good battery to the Positive (+) of the dead battery.