ALTA Flight Packs require a charger that can charge a minimum of 6 cell battery packs with balancing for all cells. There are many good chargers available on the market such as the Hyperion EOS 0720 Super DUO3 charger - 2x 1s-7s, 20A max, 1000W and the iCharger 306B. Note that the icharger model will require parallel charging and balancing leads to charge 2 packs simultaneously.
If you would like to use these charges to their full potential and power them from a wall outlet you will also need a power supply with a minimum of 1000W such as the EFUEL 1200W POWER SUPPLY or Chergery S1200
Remember to read the manufacturer instructions for all charger and power supply units before use