Multiple choice general knowledge science & technology Power units for Battery backup used at residential buildings are in : KW Volt ampere (VA) Ampere Volt Reveal answer Fill a bubble to check yourself B Correct answer Explanation Battery backup systems like UPS are rated in Volt-Ampere (VA) which represents apparent power. KW (kilowatts) is for real power, while Ampere and Volt are individual components, not the complete power rating used for these systems.