For charging of FES battery packs, only special FES chargers are approved.
FES KOP602E Charger is a modern programmable fully automatic battery charger. It stores data about charging times and Ah charged.
For charging both battery packs at the same time you need two KOP602 chargers (which are delivered with FES system standard equipment).
*If your country is using 110 V~ grid, then you should use suitable voltage step up transformer.