How to assemble a powerful li-ion battery yourself?

Question

Batteries

My custom motorized surf requires a power source. It is necessary to assemble a Li-Ion battery with approximately the following parameters: nominal voltage: ~ 51.8V, capacity: 34Ah (~ 1990Wh) weighing preferably up to 8-9 kg.
I understand surfing, but not very much about electric motors, etc. :-) in connection with which I will forgive help.
1. Is it possible in principle to assemble a battery of such power at home from components from ebay or aliexpress and give it the desired shape (wide and flat)?
2. Is it possible, in principle, to assemble a charger for such a battery at home?

Answer 1

1 Yes
2 Yes
battery 18650
34Ah / 3000mAh = 11 in parallel
51.8v / 3.7v = 14 parallel assemblies in series
46g * 11 * 14 = 7kg