Makita 18V NiCad Rechargeable Battery Rebuild Kit (Sub C 2.1A Full Size 1 5/8" Tall)
Amazon.com: 2-Pack 6000mAh Replacement for Makita 18V Batteries with 18V DC to 110V AC 300W Power Inverter, Built-in Work Light, USB Type-C, Dual USB Ports Compatible with Makita Battery - Portable Power
Makita BL 1830 Battery Repair: Fusible Link Repair
Makita and Rayovac Battery Pack Teardowns
SOLVED: How do I open them and cell replacement - Power Drill - iFixit