How Long Can a UPS Power a CCTV System?

Preface

Our customers often ask a question: How long can a UPS power a CCTV system? In fact, this is a system based question, which involves the design considerations of many aspects such as the selection of UPS, the configuration of batteries, and the power consumption of CCTV systems. This article will try to explain the problem for you from these aspects.

1.UPS with Internal Battery and Can Connect External Battery

1.1 Typical UPS with Internal Battery and Can Connect External Battery

First of all, we need to know that the function of UPS power backup needs to be supported by batteries. If we want to answer how long can a UPS power a CCTV system, we first need to know the capacity of the battery that the UPS carries. The most common type of dedicated UPS on the market has a built-in battery or an external battery. This type of UPS is often stable, of reliable quality, and produced by a reliable brand. It is widely used in the field of Telecom and ICT. The price is relatively high.

This type of UPS has a built-in battery, which can support the entire system operation through the battery when the utility power is offline. Of course, because the capacity of the internal battery is very small, how long does it usually last. In many cases, when the utility power is offline, the system can run on the battery for a long time, so an external battery is required.

Note: Vertiv UPS Datasheet

Pictured above is Veritiv’s Liebert series UPS. This model of UPS has a built-in lithium battery, and an external battery can also be used. This type of UPS is also common in other brands. So how to distinguish this type of UPS?

The above picture is taken from the datasheet of the Vertiv Liebert series. Among the 1000VA models, we found that the full-load runtime was 13 minutes. In the following sections we will base our calculations on this data.

1.2 Internal Battery Scenario Caculation

It is known that the UPS has 1000VAcapacity, and the battery can support a full load run time of 13 minutes. Based on this data, we can calculate the built-in battery capacity. The calculation is as follows:

UPS Internal Battery Total Electricity = UPS Power(VA)* Power Factor * UPS Full Load RunTime( Hour) = 1000* 0.8 * (13/60) = 173.3Wh

Note that the Power Factor parameter is used for the conversion of power VA and Watt. The principle here is more complicated to explain clearly, because we are only a general engineering application, and the value of 0.8 is generally sufficient in this scenario. In this way, we get the power of the built-in battery of the UPS. We need to use this parameter to calculate how long can a UPS power a CCTV system.

We first need to check the camera’s datasheet to find its key specification parameter max power. Let’s take the following Axis M2035-LE Bullet Camera as an example:

Generally, you can find the power section in the datasheet of the camera, and there will be a detailed description of the power. We can know that the maximum power of this camera from Aixs is 12.95W. With this parameter and the UPS Internal Battery Total Electricity= 173.3Wh we calculated just now, we can calculate how long can a UPS power a CCTV system:

UPS Power CCTV System Time= UPS Internal Battery Total Electricity/Camera Max Power = 173.3Wh/12.95W= 13.38 hours

If we put all factors together to see formula to calculate as following:

UPS Power CCTV System Time =UPS Internal Battery Total Electricity/Camera Max Power

= (UPS Power(VA)* Power Factor * UPS Full Load RunTime( Hour)) /Camera Max Power

1.3 External Battery Scenario Calculation

External Battery Electricity = Battery Voltage(V) * Battery Amps hour (Ah)

We have previously known that Vertiv Lieberty Series UPS the external battery voltage is 48VDC. Assuming our battery has 50Ah, then we can get the following:

External Battery Electricity =48V * 50Ah =2400 Wh

Generally speaking, the UPS will only discharge 80% of the total battery capacity, so the actual external battery available capacity = 2400Wh * 80% = 1920Wh

Knowing that the maximum power of the camera is 12.95W, then we can get the UPS Power CCTV System Time:

UPS Power CCTV System Time =UPS External Battery Total Electricity/Camera Max Power

=(Battery Voltage(V) * Battery Amps hour(Ah)*80% ) / Camera Max Power

= 1920Wh/12.95W = 148.26 Hours

So with our assumed battery configuration, How long can a UPS power a CCTV system = 148.26 Hours

2.UPS with Only Internal Battery

There are also many UPS on the market that only have built-in batteries and do not support external batteries. This type of UPS is usually used in some low-power scenarios and general office scenarios. The general power is between 300-800VA. Based on this type of UPS, we only need to figure out the capacity of its built-in battery and calculate it. The following takes APC’s BK500/650VA as an example to analyze:

Note : APC BK500/650VA Datasheet

We can see that the type of battery here is a lead-acid battery with a capacity of 12V/5VAh. We can calculate the battery level based on this. Reminder, for the basics of calculating battery capacity, please refer to: How long can a UPS power a CCTV system Chapter 4. The simple derivation is as follows:

Internal Battery Electricity = Battery Voltage(V) * Battery Amps hour (Ah) = 12V *5Ah =60Wh

As we have said in the previous chapter, generally UPS will keep 20% of the battery space unused to avoid deep discharge, so we can get the actual Internal Battery Electricity as 60Wh*80%=48Wh

We already know that the maximum power consumption of the camera we are going to use (defined in the previous chapter) is 12.95W. It can be calculated as follows:

UPS Power CCTV System Time =UPS External Battery Total Electricity/Camera Max Power

=(Battery Voltage(V) * Battery Amps hour(Ah) *80%) / Camera Max Power

= ((12V*5Ah)*80%)/12.95W = 3.7 hours

So it can be calculated that for a camera with a maximum power consumption of 12.95W, this model of UPS can support the system to run for 3.7 hours.

Note that these are theoretical calculations. But the actual whole CCTV system needs to add POE switch, multiple cameras, and other related systems. Therefore, the battery capacity of such UPS is far from enough.

3. The Gap Between Theoretical Calculation and Practical Deployment

3.1 Note that CCTV System is not just a Security Camera

CCTV system is a system that includes a lot of equipment. Therefore, when we calculate how long can a UPS power a CCTV system, we must calculate the maximum power consumption of all equipment, and do not miss it. From the wrong calculation of the system autonomy time, it will affect the reliability of the entire system.

3.2 Most CCTV Scenario is Outdoor

Most CCTV systems are deployed in outdoor environments. The outdoor environment is relatively harsh. There will be problems such as high temperature, high humidity, high salinity air, and difficulty in on-site maintenance. Therefore, the UPS we used as an example in the previous article is only for everyone to better understand the calculation process, and it is actually not suitable for deployment in an outdoor environment. We recommend using Edgeware’s all in one IP65 outdoor UPS system for the outdoor CCTV scenario. We have introduce the related experience in The Story of Edgeware Outdoor UPS Enclosure for Video Surveillance , welcome to read.

4. Summary

Here, we have answered How long can a UPS power a CCTV system in detail? You will find that this problem is actually related to the battery configuration of the UPS and needs to be calculated to obtain it. Please refer to the formula in the text. If you have any questions and suggestions, please contact us.

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