What happens when the power goes out at your home or office? Laptop and mobile devices can switch over to their built-in batteries. However, anything without a battery immediately shuts down.
An Uninterruptible Power Supply, or UPS, offers battery power to any device connected to it. Here’s a Tech Tip video from Eric Murcia on why you should use a UPS. Today, we’ll cover how to pick out the right UPS.
Types of UPS Devices
Only three types of UPS devices exist: standby, line-interactive, and online. Standby units cost less and are the most common. If the model doesn’t mention a type, then you’re looking at a standby unit.
A standby unit charges its battery and waits for a power outage. Once the power goes out, the UPS switches over to battery power. A 20-100 millisecond delay occurs between the switch. This delay falls well within most device tolerances to prevent power failure.
Line-interactive UPS devices work very similarly to standby units. However, these units include a transformer that offers your devices more protection from brownouts and power sags. In general, we recommend spending the extra money on one of these. Your devices will thank you.
These units provide power to devices exclusively through the batteries. The batteries charge constantly unless the power goes out. This type of unit offers the most protection, but that protection costs much more. Typically, prices run 200-400% higher than a line-interactive UPS. Unless you run a data center, you don’t really need to pick this option.
How Much UPS Do You Need?
Calculate Wattage and VA
First, you need to know how much power your devices use. You can measure this in a couple of ways. The accurate method involves using a power meter (like the Kill A Watt Meter) to measure the exact wattage for every single device. The meter will supply you with real-usage numbers.
The conservative method involves looking at the power ratings on each device you’ll have connected (computer, monitor, etc.). For example, your computer might have a 400W power supply, and your monitor might use 100W. In reality, devices actually use less power than their rating, so this is a safe estimate.
No matter how you get the numbers, add the wattage for each device together. From our example, our devices use a total of 500W. Multiply that total by 1.6 for your minimum Volt-Amperes (VA). Volt-Amperes are used to measure the capacity of UPS units. We’ll use this number to select the right UPS unit next.
Unfortunately, there’s no good way to calculate runtime. Instead, UPS manufacturers like APC, CyberPower, and Tripp Lite offer tools to help find the right UPS unit for you. Armed with your Watts and VA, take a look at one of these sites:
Add your VA and/or Wattage to filter the list down to UPS units that will provide the right amount of power. Each unit varies when it comes to runtime.
Choose the runtime that matches what you want to accomplish. In general, the goal isn’t necessarily to keep working. At a minimum, you just need enough time to save your work and shut down your system. Regardless, you should be able to pick out the UPS unit that best fits your needs!