Not even close for power compatibility. Power supplies are rated for output not input and you can count on roughly 85% efficiency. Mongrel breed generators seldom if ever can sustain maximum advertised load rating.
For maxxing the power supply you most likely will need 4,000 watts. L.A. gets hot and a marginal generator is extremely likely to overheat and die. You can back off the charging at the expense of generator run time.
Same wattage you will have 1/4th the amperage at 56 volts (48 volt system when charging) as you would at 14 volts charge rate.