Hart 20V batteries are designed as part of a closed system. The safety protections—such as over-current protection, thermal cut-offs, and low-voltage disconnects—are often shared between the battery's internal circuitry and the specific electronics inside the official Hart tools and chargers. Attempting to draw power for external devices or using non-standard charging methods can bypass these protections, leading to permanent cell damage, fire, or leakage. Handling Precautions

Despite the "20V" marketing label, Hart 20V batteries are identical in voltage to standard 18V lithium-ion battery packs. Key Electrical Specifications 20.0 Volts Nominal Operating Voltage: 18.0 Volts Cut-off Voltage (Fully discharged): 15.0 Volts

, ensuring each internal lithium-ion cell stays at a safe, equal voltage (roughly 4V increments: 4V, 8V, 12V, 16V relative to Negative). Safety and Compatibility Resetting: