Battery/Electric inverter system is constructed within the sub floor frame of unit A trailer. 
Is intended for backup power with seamless auto/switch, at show power loss, maintaining up to 14 hours of insured power. 
When operating on battery, HVAC circuits are not supplied, B unit tractor generator would be implemented.

AC/DC power supply is an AIMS Power 6000 Watt Pure Sine Inverter/Charger, operating at 240Vac or 24Vdc input, with 10 msec transfer time, delivering 120/240Vac split phase, 30ah x 2 = 60ah output.

BATTERY DESIGN | THE MATH
Battery power is supplied by twelve 6 Volt Deep Cycle maintenance free batteries.
Battery capacity rating is 220ah each.
The 12 batteries are cabled in series; in groups of 4, increasing the voltage, creating three 24Vdc 220ah quad cell banks. 
Tying the 3 banks together in parallel manufactures one 24Vdc 660ah battery array.

Dividing the normal technical equipment metered AC load of 24ah into the 660ah battery array = 27.5 hours of 24Vdc capacity.
Calculating; (for battery life safety maintenance), a necessary depth of discharge safety margin of 50%, allowing usage of a "soft" 14 hours of technical equipment inverter battery operation with safety.

Formula: 660ah/24ah=27.5h/50% (depth of discharge) = 13.75 hours.