Better late than never about the A123 cells...…………. I have them in a floor vacuum cleaner. I have a FMA very smart charger. It is set for ONLY LIFEPO4 cells I made the 3 & 4 cell packs 10 years ago ? I run it down to 5 % or 10 % left every weekend. They still charge up to between 90 & 100 percent 3.6 Volts per cell is maximum BALANCED full charge.
Yes you can store them fully or at about 25% charge & nothing bad has ever happened.. In all the years & over a dozen 3& 4 cell packs of A 123 Both 1100 & 2300 mahr sizes. Old stuff.