@davek79 you’re right, it’s about the cell chemistry.
However the only reason why we’re all talking about 12s is because of the Bonka (or Multistar) Batteries are the preference of most of the future OpenPPG-Pilots. They are Li-ion Pouch cells with a 6s configuration per battery pouch - so two of them then make for the 12S / 44,4V configuration.
However:
Paul ( @Pdwhite ) stated in the above post, (Time until battery is out of charge? - #19 by Pdwhite ) that the OpenPPG is a 48Volt setup (which would be a sort of standard similar to Ebikes) - and that would be a 13S setup, if Li-ion cells (with nominal 3,7V) are used. That’s not possible with the Bonka or Multistar Pouch Batteries, but it is possible if you DIY your battery pack with the 18650 Li Ion cells.
Someone suggested the use of a wiki, since there’s so much information spread across so many posts in the forum - I would agree that a wiki would be very useful at this point 