HR000000000
H Hybrid: Denotes some prepurchased or hard to find components
R Robotics: suitable for robots
buy: 4s 40A BMShttps://www.aliexpress.com/item/4000025857655.html
(can't specifically vouch for this vendor, just chose the first that
came up)
make sure to choose 4s and balance
find or buy materials: duct or gorilla tape, trashed computer...