What are UPS Systems?
The Sizing Method
- Calculate the Load Requirement in Ah
- Calculate the Battery Capacity in Ah
- Calculate the Desired Charge Current
Begin by calculating the required load backup in Ah. The formulas are as follows:
• Load (A) x backup time (hours) = Ah
• Load (W/V) x backup time (hours) = Ah
Following are a couple of examples of how to calculate the load in Ah:
Example 1: 6A continuous load at 24VDC for 8 hours
6A x 8hours = 48Ah @ 24VDC
Example 2: 15W continuous load at 12VDC for 24 hours
15W/12V x 24hours = 30Ah @ 12VDC
Some other considerations for load calculations:
• Loads at non-system voltage to include inefficiencies (inverters, DC/DC converters)
• Intermittent loads should be averaged
• Future expansion considerations
• Factoring in uncertainty on run-time or power-draw (radios, pumps, lighting)
• Consider inrush current for AC loads, making sure inverter is properly sized to handle
Summing it all up!
UPS Systems are reliable power systems provide backup power to the load during power failure. Correctly sizing them means calculating the load, battery capacity, and desired charge current. Fortunately, SunWize does all of this legwork for you through our System Sizing Form. Prefer to speak to someone directly? Contact us via chat or by phone at (866) 827-6527.