Multiple possible causes. Diagnose in this order.
- Check battery temperature. Do not charge a hot battery. Let it cool to room temperature (10°C - 40°C / 50°F - 104°F) first.
- Verify battery type. Only use BL1815N, BL1820B, BL1830, BL1830B, BL1840B, BL1850B, or BL1860B cartridges. Others may cause poor performance.
- Assess your usage. Are you pressing excessively? This overloads the tool and drains the battery quickly. Use the correct speed setting: Low (1) for high-torque tasks.
If the operating time has become excessively short, stop operating immediately. It may result in a risk of overheating, possible burns, and even an explosion. The battery may be damaged.
Heads up: Never use a damaged battery. Do not store the tool and battery where temperatures exceed 50°C (122°F), as heat permanently reduces battery life.