The universal chargers from MEANWELL to charge the battery packs. See the various product lines:
MEANWELL PB-360/PB-600/PB-1000 models for 12V, 24V and 48V.
MEANWELL HEP-600 models 12V/24V/48V with passive cooling.
MEANWELL HRP power supplies for single cell charging 3.6V, currents 15A to 120A.
MEANWELL = Quality products for your DC applications. Order from GWL instantly.