Makita BL1840B 18V LXT 4.0Ah Battery – Fast Charge, Long Runtime

Overview and capabilities

The Makita BL1840B 18V LXT battery is engineered to keep cordless tools ready when you need them most. With a 4.0Ah capacity, it delivers extended run time and a notably shorter wait between sessions thanks to a full charge in about 40 minutes when used with a compatible Rapid Optimum Charger. An integrated LED charge level indicator lets you view remaining power at a glance, helping you plan swaps and schedule work without guesswork. Designed to resist self-discharge, the battery stays ready for action even after longer storage periods.

Key advantages

• Up to 35% more run time per charge than the BL1830 model.
• Reaches a full charge in 40 minutes or less with the Rapid Optimum Charger.
• LED charge level indicator for quick, at-a-glance status checks.
• STAR Protection Computer Controls help guard against overload, over-discharging, and overheating.
• Reliable power in extreme temperatures, including very cold conditions.

Real-world use cases

• Prolonged framing, drilling, or cutting sessions with fewer tool swaps and interruptions.
• Outdoor or indoor projects that require sustained cordless power over many minutes of work.
• Work in dim or high-contrast environments, where the LED indicator supports planning and tool management.

Care and compatibility

• Designed for Star Protection tools, indicated by the Star Symbol or Yellow Battery Receiver under the tool.
• When paired with Makita Rapid Optimum Charger (sold separately), the charging system communicates with the battery to optimize life, voltage, and temperature.
• The charger includes a built-in fan to cool the battery for faster, more efficient charging, even in hot weather.
• Part of Makita’s expansive 18V LXT cordless tool ecosystem for seamless tool-to-battery pairing.