Amazon.com: Lithium Ion Battery Case Parts Replacement for Makita 18v 3ah BL1830 BL1830B 4ah BL1840 BL1840B 5ah BL1850 BL1850B 6ah BL1860 BL1860B Battery, 5.0Ah Plastic Cover Repair Kit with Circuit Board :
Makita 18V NiCad Rechargeable Battery Rebuild Kit (Sub C 2.1A Full Size 1 5/8" Tall)
1820 Makita® 18V Battery Rebuild Service – MTO Battery
Makita Bl1850 Battery Replacement 18V Electric Lithium-Ion Coreless Power Tool Power Supply Machine Tool Battery Power Supply Battery Charger Power Inverter - China Battery Pack, Replacement Battery | Made-in-China.com