If your battery flashes specific patterns on its Built-in Fuel Gauge , it may indicate a temperature out-of-range error or a permanent cell failure.
By correctly identifying these pins, you can safely adapt Hart batteries for robotics, emergency lighting, or custom power supply builds. Always double-check with a multimeter before making connections, as manufacturers may revise internal layouts without changing the external shell. Hart 20v Battery Pinout Diagram
Never short B+ to B-. Always use a fuse (5A-10A) and monitor cell voltage to avoid deep discharge below 15V total. If your battery flashes specific patterns on its
Used by the charger to monitor heat. It prevents charging if the battery is too hot or cold. Never short B+ to B-
Are you looking to build a for another tool, or are you trying to repair a battery that isn't holding a charge? Hart 20v Battery Pinout Wiring Diagram
| Pin Number | Label | Function | |------------|--------------|------------------------------------------------------------| | 1 (Left) | | Battery Positive (+), 20V Max (21V hot off charge) | | 2 | CH or ID | Charge enable / Thermistor or ID resistor (depends on model) | | 3 | C or S | Communication (SMBus Data line) – talks to charger & tool | | 4 | B- Sense | Negative sense / Cell tap (sometimes unused) | | 5 (Right) | B- | Battery Negative (-), ground |