Digital Trends

APC Back-UPS ES 725

March 10th, 2004 | by Jeff Fila

Testing and Use

We tested the Back-UPS ES 725 with an AMD Athlon XP 2800-based PC powered by an Antec TruePower 330W power supply and a Samsung 955DF 19-inch monitor.

Initially, PowerChute told us that we had about 55 minutes of battery backup time but we knew that was not accurate. With our 330W power supply and monitor that draws about 100W, we knew we were close to pushing the limits of the ES 725 already and that 55 minutes was not reasonable. However, just because you have a 330W power supply does not mean you are using that much power; power usage is based on what the components in your system draw.

In order to get a more accurate estimate of battery backup time, you need to simulate a power outage once and let the UPS and PowerChute manage it. APC doesn't suggest this, or even mention it as far as we can tell, and the only need to do this is if you want a good initial estimate. The unit will not try to keep the system on longer than it can — it will dynamically update the estimate as it starts discharging.

We started the testing by simply unplugging the UPS from the wall. Immediately upon a power failure (or simulation of one in this case) the UPS takes over and you receive a popup box that says “your battery backup is now supplying battery power to your equipment.” The audible alarm we mentioned earlier is sounded and produces four beeps every 30 seconds. This alarm can be turned on or off in the PowerChute management console.

After unplugging the UPS from the wall the estimated battery time remaining and the battery capacity as shown in PowerChute started going down. After 7:48, the computer was forced to go to hibernate mode. The battery showed 39% capacity remaining. For safety reasons, the system will shut down once there is five minutes of battery time remaining.

PowerChute shows the current status of your UPS, including the reason it last went to battery power.

These results are on-par with what APC suggests on their Website. They provide a runtime chart to help you decide what size UPS is best for your applications, and they showed a system with a 300W draw getting about seven minutes of runtime.

Since this is a high-capacity battery, you won't be able to recharge it quickly like batteries for your camera. Recharging took us several hours which was expected. This shouldn't be a concern unless you experience frequent blackouts — if you do, you probably have bigger problems than the time it takes to recharge your UPS.

After several hours, our UPS was back to full capacity, showing 100% in PowerChute. The estimated battery time had changed from the default 55 minutes to the more reasonable 17 minutes. We pulled the plug again and let the UPS take over. PowerChute shut the system down at 80% charge, because that is when it had only five minutes of backup left. At 80%, it took over an hour to recharge to the full 100%. Remember also that the battery will take longer to charge when you are also using the computer that is connected to it than if that computer was turned off.

As far as surge suppression goes, in our weeks of testing we never experienced any power fluctuations or other events and could not test validate surge protection claims. However, since APC has built their business around surge and power protection for almost two decades and is known as an industry leader, we feel confident in their products' ability to handle such situations.