My husband and I are in the process of ordering a 2017 Transit van that will be used largely for travelling with our 6 dogs. We are getting the heavy duty alternator and dual batteries and are wondering what size inverter the factory installed dual batteries would be capable of supporting. Is a 2000w inverter unrealistic?..what about 1000w? We're not looking have that high of a load on with the engine off...just want to know what its capable of and there's very little information on the batteries and alternator that I can find! Thanks!