Delivers the full voltage of the battery pack (nominally 18V, peaking at 20V when fully charged). 2. Negative Terminal (-) Location: The outermost slot on the opposite side. Function: The common ground for the circuit. 3. T-Terminal (Thermistor / Temperature) Location: One of the inner pins.
Unlike older NiCad batteries that only had a positive and negative terminal, the HART 20V (lithium-ion) system uses a multi-pin configuration to communicate with the tool and the charger. This protects the cells from overheating and over-discharging. hart 20v battery pinout diagram better
HART batteries have internal protection, but the tool often handles the final low-voltage cutoff. If you run a HART battery directly into a motor without a protection circuit, you risk draining the cells below 2.5V, which can "brick" the battery, making it unchargeable. Delivers the full voltage of the battery pack
The "better" way to look at the HART 20V pinout is to view it as a communication system rather than just a power source. While the outer pins provide the muscle, the inner pins provide the intelligence. Function: The common ground for the circuit
Some modern HART brushless tools won't spin unless they detect a specific resistance on the middle pins. This prevents people from using "dumb" power sources that might damage the tool's electronics. Safety Warning Working with lithium-ion batteries is inherently dangerous.