The battery pack has reached its maximum thermal limit and shut off to protect itself. Immediately stop and allow the tool and battery to cool down completely in a well-ventilated area. Do not attempt to put it back on the charger while hot.
- Let it cool: Place the tool on its side on a stable surface, away from anything flammable.
- Check for overwork: Were you forcing it or using it continuously? Do not force the power tool. Use the correct tool for the job.
- Inspect: Once cool, check the air vents. Keep your hair, clothing, and gloves away from air vents. Vents cover moving parts and must be clear for cooling.
If that didn't work, a faulty cell in the battery pack can cause overheating. Do not use a battery pack that has received a sharp blow or is damaged. If the battery case is cracked, do not insert it into the charger. Return it to a service center.
Heads up: For longest life, don't store or use the tool where temperatures reach 105°F (40°C).