Charger / Power Supply help...Please.

[Lemski]

How do I know what power supply will be needed for my charger? Is it all about wattage? Or ampage? I don't wanna buy a decent charger and it underperform because it's under powered!

Specs of charger are;

Input voltage range: 10~28.0VDC
Charging current range: channel 1/2 0.05~20.0A
Discharging current range: channel 1/2 0.05~20.0A
Maximum charge power capacity: 300W@input voltage >18V (Per Channel)
Maximum discharge power capacity: 20W
Maximum regenerative discharge power capacity: 300W
Maximum external discharge power capacity: 500W@25V/20A
Current drain for balancing: < 350mA
Balance accuracy: < 10mV
Lithium (LiPo/Lilo/Life) battery cell count: 1~6 series (In non-balance mode, Life cell count can be expanded to 8S)
NiCd/NiMH battery cell count: 1~17 series
Pb battery cell count: 1~12series (2~24V)
Battery setup memories: 10