Quantity   Component name
6 × 18650 Li-ion batteries Either you buy them or you get them from old laptop batteries
3 × TP4056 charge control module 5V 1A straight from China
1 × 3s 20 A BMS battery protection board Pick the current rating you need
3 × 220 VAC to 5 VDC isolated switching converters Isolated is the key part
1 × XT60 connector