On the page you linked me it says each one is 22.2 volts though.
"I really like tinkering with Electricity."
Likewise. It's like a silent, powerful butler or genie which can be put to any use. As Captain Nemo said:
"There's a powerful, obedient, swift, and effortless force that can be bent to any use and which reigns supreme aboard my vessel. It does everything. It lights me, it warms me, it's the soul of my mechanical equipment. This force is electricity."
The 6 cell packs have a 22.2v nominal charge. 2 would work for a 48v.
Each Cell is 3.6v Nominal with 4.2v fully charged. Think like regular ole alkaline batteries where an AA is 1.5v :)
I have no affiliation with Hobby King they are just a cheap place to get battery packs motors speed controllers and other tinkering gear.
https://hobbyking.com/en_us/batteries/lipo-batteries-all-brands.html