UPS Runtime Calculator Watts for Home Labs

An Uninterruptible Power Supply (UPS) provide backup power to electronic equipments in the event that the primary power source to which the equipment is connect fails. Many individuals believes the sticker on the front of the UPS contains all of the information that is necessary to understand for how long the UPS will ran. The sticker may contain an VA rating of the UPS.

The VA represents the apparent power of the UPS, but the power that the UPS’s protected equipment draw is the real power, or the watt. The relationship between the VA rating of the UPS and the watt measurement is based on the power factor of the UPS. In order to calculate the length of times that a UPS will run when the power fail, it is necessary for an individual to understand both the VA and the power factor of that UPS.

How Long Will My UPS Run?

The length of time that a UPS will run is dependent upon an amount of load that is connected to that UPS. Small loads, such as a router and an ONT, may only draw thirty watt of power. However, a load that is comprised of devices like a four-bay NAS may draw one hundred twenty watt.

The longer that the UPS is required to provide power to those connected device, the less time that the UPS will have to perform its essential task before the batteries of the UPS are completely drain. Thus, the longer that the devices that are drawn upon from the UPS require double the wattage, the half the runtime that the UPS will have before failing. However, doubling the wattage of the load of the UPS does not necessarily indicate that the runtime of the UPS will be halved; efficiency curve, battery age, and temperature may impact the ability of the UPS to provide power for the length of time that is indicated by the wattage calculation alone.

To account for these variable, the calculator that is provided on this page help to provide an accurate estimation of the runtime of the UPS. The efficiency of a UPS is not a constant value; the efficiency of a UPS may change based upon the load of the UPS. For instance, the efficiency of a line-interactive UPS may be best provided at half the load of the UPS; adding more device to the UPS may reduce the efficiency of the power that is provided by the UPS.

Another example is the efficiency of online double-conversion UPS units, which may provide less efficiency at light load, but may still provide the same efficiency if the load increase. These efficiency curves for various type of UPS units are provided in the result that are obtained from utilizing the calculator. Efficiency is an important value for understanding whether or not external battery pack should be added to the UPS, or whether the load that is drawn from the UPS should be reduced.

Battery chemistry and the age of the batteries also impact the runtime of a UPS. Sealed lead-acid battery lose their capacity over time; after the first year of use, they lose their capacity at a steady rate; warm environment worsen that loss of capacity. Lithium iron phosphate battery do not lose their capacity as quick as sealed lead-acid batteries, but even these batteries lose their capacity after several year of service.

Because batteries lose their capacity over time, an individual should not assume that a three-year-old UPS will have the same amount of runtime as that same UPS when it was new. An age field is included in the calculator so that the runtime estimate take into account the age of the batteries. Reserve capacity is a requirement of the power plan of a UPS, yet is often overlooked by individual.

An individual should allow for fifteen to twenty-five percent of the battery capacity of the UPS to remain unused. If the batteries are allowed to drop to such a low percentage of their designated capacity, it allow the system to safely execute a clean shutdown of the system. A clean shutdown allow for the operating system to flush any data on the disk from that computer system, or to cease the operation of virtual machine in virtual private server.

By leaving a portion of the battery capacity of a UPS unused and by subtracting that portion of the capacity from the total capacity of the batteries of the UPS, the life of the batteries is extend. This type of calculation is important to include in providing an estimation of the length of time that a UPS will run. Other factor that can impact the function of a UPS include the temperature at which the UPS is locate and the peak wattage draw of the devices that is connected to that UPS.

If the UPS is located in a warm area of an office, for example, the batteries of the UPS will lose their capacity to provide power. High temperature will cause the batteries of a UPS to lose their capacity to provide power quick. In addition, device may experience spike in the draw of power from the UPS; for instance, when a computer system’s CPU increase to provide more power to a specific program, or when the disk of a computer system begin to spin up.

In these instance, the power draw of the system may increase to a level that exceed the capacity of the UPS. The ability to enter the temperature of the system and the estimated peak draw of the devices allow for an accurate estimation of the runtime of those device. In order to obtain the most accurate result from the calculator, an individual can measure the actual load of the device with a plug-in meter.

The wattage that is indicated on the device is often inaccurate when the device are idling. By measuring the actual draw of power by the device, an individual can make informed decision regarding the operation of the UPS and its battery. These measurement can help to an individual to decide whether external battery pack should be purchased, how much reserve capacity should be allowed, and how long the UPS will remain online before failing.

One of the main goal for utilizing this calculator is for an individual to understand how long their UPS will remain online in the event that the power fail in the primary location.