VANON 2Pack BL1850B 5.0Ah 18V Replacement Battery for Makita 18v Battery Lithium Compatible with Makita 18 Volt Battery BL1815 BL1820 BL1830 BL1840 BL1850 - - Amazon.com
Amazon.com: Amityke Battery Adapter,Power Wheels Adapter for Makita 18V/14.4V Battery BL1820, BL1830, BL1840, BL1850 with 14 awg Wires Power Convertor for DIY Ride On Truck, Robotics, RC Toys and Work Lights :
Amazon.com: MechanicAnts MA21007 Lithium-Ion 20V MAX 4.0Ah Battery for All Power Tools, Compatible with Makita BL1840 : Tools & Home Improvement