Make a Tiny Battery for LEGO Power Functions : 4 Steps - Instructables
WORKING* LEGO Battery Box White Electric Sound Light Engine Rocket 30351 30353 | eBay
Amazon.com: DooQi CADA Technik Power Function Kit for Technical Cars, Including 3 Motors, LEDs, Battery Box and 2.4 Ghz Remote Control (Compatible with Many Models Such As CADA) : Toys & Games
Amazon.com: LEGO Mindstorms EV3 Rechargeable DC Battery (45501) : Toys & Games
Battery Box 88015 | Powered UP | Buy online at the Official LEGO® Shop US
Amazon.com: LEGO Power Functions AAA Battery Box 88000 : Toys & Games
Batteries and Battery packs
LEGO DUPLO Town Steam Train 10874 Remote Control Set - Learning Toy and Daycare Accessory for Toddlers, Boys, Girls, and Kids 2-5 Years Old, Push and Go Battery Powered Set with RC
Alternative LEGO Rechargeable Battery Box (8878) – Green Gecko Workshop