Chargers for the Bonka 7S?

Can anyone tell me the best charger(s) to buy to power the Bonka 7S. I have 4 of them and would love to be able to charge them all at the same time if possible.
Thank you in advance for any information on types, brands, and where I can get them online.


You will need a 24vDC power supply for each of these, with the highest wattage you can get (mine are 360watt/15A). You can usually find the best deals on those on ebay.