[EVDL] car charging eco flow

[redscooter via EV]

 i have a ecoflow with 120 volt  pure sine wave output and capable of 
800 watts.
i normally charge 120 off my house.  but wan to use the eco flow with my 
off grid solar/ n batteries to charge my car.
the ecoflow and other invertors has 3 prong  plugins, but the charging 
will not start? is a grounding issue ?
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