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: Gamrombo 2Packs Upgraded to 6.0Ah 18V BL1860B Li-ion Replacement Battery Compatible with Makita 18V Battery BL1815 BL1830 BL1835 BL1840 BL1850 BL1860 LXT400 194205-3 Fit Cordless Power Tools : Tools & Home
Amazon.com: SUnMilY for Makita 18v Battery, 6.0Ah Replacement Lithium Batteries Compatible with Makita Battery 18V BL1860 BL1850 BL1850B BL1840 BL1840B BL1830 BL1830B BL1815B (4 Pack) : Tools & Home Improvement
For Makita 18V 6.0Ah LXT Lithium BL1830 BL1850 BL1860 Battery / Fast Charger US | eBay
Makita 18V LXT Lithium-Ion High Capacity Battery Pack 5.0Ah with Fuel Gauge BL1850B - The Home Depot