Does the tool battery have overcharge and discharge protection

Optimised Power: The technology ensures that the tool receives the optimal amount of power from the battery, preventing overloading and maximising performance. Protection Against Overheating: If the tool or battery begins to overheat during use, the technology can automatically reduce power to prevent damage and ensure safety.

There will always be some voltage left even when the battery pack no longer runs your tools. They are considered discharged at 1.1V per cell. Using the tool is the safest way to discharge these types of batteries. NiMH batteries have a higher capacity, so they hold more power, but they let it out at a similar rate to the Cadmium batteries.

When your rechargeable power tool batteries have reached the end of their life do not throw them in the trash. As batteries corrode, their chemicals soak into the soil and contaminate groundwater and surface water. Lithium batteries could even cause a landfill fire. Be responsible and take them to your local hazardous waste pickup.

These tools provide battery over-discharge protection. Some models include a third terminal on the connector, positioned on the left or middle side, as illustrated in the photo. The third pin in the connector functions as a thermistor, serving as a temperature sensor for additional overheat protection when required.

Inside that battery pack is a lot of little rechargeable batteries. Often they are wrapped tightly together with plastic Rechargeable power tool batteries come in mainly three types. Nickle-Cadmium, Nickle-Metal Hybride, and Lithium-Ion. You may be choosing a tool brand and have no idea what type they use. Nickle-Cadmium = NiCd

For all these safety and compliance considerations, batteries are not cross-compatible (unless specified by the power tool manufacturer). When buying aftermarket batteries for power tools, it is important to consult with the power tool owner's manual and purchase only the batteries recommended by the manufacturer.