Detailed AC system design

Inverter efficiency	.85

#	Load	Quantity	Watts	Total watts	Duty cycle	Surge factor	Surge Watts	Power factor	Volt-amperes (VA)	Hours per day	Days per week	Average daily AC watt-hours
1	Generic laptop	1	15 W	15 W	1	0	0W	.45	33 VA	4 hours	30 days	71 Wh
2	Generic cell phone	2	5 W	10 W	1	0	0 W	.5	20 VA	1 hour	30 days	12 Wh
3	Generic blender	1	600 W	600 W	1	3	1800 W	.8	706 VA	.05 hour	10 days	12 Wh
4
5
6
7
8
9
10
Total average daily AC watt-hours												95 Wh
Total VA												759 VA
Total VA with surge watts												2559 W

• Load: The make and model or type of load.
• Quantity: The number of of that particular load.
• Watts: The power rating in watts for the load.
• Total watts = quantity × watts
• Duty cycle = Rated or estimated duty cycle for the load. If the load has no duty cycle a value of 0 should be used. A load with a duty cycle of 20% would be inputted as .2
• Surge factor = Rated or estimated duty cycle for the load. If the load does not have a surge requirement a value of 1 should be used. Common values are between 3-5.
• Power factor = Rated or estimated power factor for the load.
• Volt-amperes (VA) = Total watts ÷ Power factor
• Hours per day: The maximum number of hours the load(s) will be operated per day. If the load has a duty cycle 24 hours should be used.
• Days per week: The maximum number of days the load(s) will be operated per week.
• Average daily AC watt-hours = Total watts × Duty cycle ÷ Inverter efficiency × Hours per day × Days per week ÷ 7 days
• Total average daily AC watt-hours = sum of Average daily AC watt-hours for all loads
• Total VA = sum of volt-amperes (VA)
• Total VA with surge watts = sum of Surge watts for all loads + Total VA