[Al Skierkiewicz]

A few things...
The six station charger is available in 120 volt version. We have used one for years and they work great. Why this one is listed at 220 volts is beyond me but it may be for an intended audience whose country is at 220 volts. The manufacturer is right here in Illinois. While the chargers are listed as 5 amps per station, they do not supply 5 amps continuously. The output current is varied for a variety of conditions dependent on cell voltage and time. These smart chargers switch charge current on and off while they are testing the battery condition.
I would suggest to event coordinators that teams be encouraged to remove their batteries each night to be charged back at their hotel. Please be advised that precautions need to be followed as charging batteries do have a chance of releasing hydrogen and on occasion, batteries have failed during the charging process. I recommend that charging be monitored by adults and that batteries be disconnected during sleeping hours. I would also like to recommend that event coordinators have a charging station somewhere for teams playing in finals.