Remember, 50 amp service IS 100 AMPS of service. Each 15k at 100 degrees ambient will draw 15 to 16 amps each. We sold Mandalay(Texas where it gets 100 to 105), and 2 15k AC units should cool your RV with no problem. IF you are going into temps above 105, then the 3rd unit will do great. The Genset is rated at 63 amps total draw. IF you have the Intellitec EMS system, that 63 amps will kick out the EMS parameters if you go over that 63 amps when the Genset is running. The Intellitec KNOWS what the Genset amp supply is. Have you had your existing AC's checked for correct output? Doug