I use 3 Cell packs for my 12v applications. Fully charged they are 12.6v (4.2v/Cell) discharged they are about 10.8 I tend to not discharge them below 3.4v/Cell. You could run 3 in series fo 36 Volt the only down side is that you would need to either remove all 3 packs to charge them or use a bunch of balance Chargers and just keep them all hooked up all the time on the balance port.
Most things set for DC have a operating range of voltage. IE automotive accessories are about 10-15v
I really like tinkering with Electricity. I currently replaced my gasoline chainsaw and trimmer for the 40V ryobi series. I was pleasantly surprised when the trimmer head used all my old 32cc gas accessories brush blade and pole saw. Best part is that I charge my batteries off my little off grid solar setup. 200w of panels to a 100 AH 12v battery bank with a 300w 110 inverter.
On the page you linked me it says each one is 22.2 volts though.
Likewise. It's like a silent, powerful butler or genie which can be put to any use. As Captain Nemo said:
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