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How to Calculate Your UPS/inverter Battery Back-up Time?

Most people these days depend on inverters for uninterrupted power supply for office work and household chores. No one has the time or patience to sit around and wait for the grid power to get restored since there is so much to do. However, very few know how to calculate UPS load and backup time. They often end up asking the salesperson and rely on their words rather than figuring it out themselves. 

But what you need to remember is, calculating your UPS/inverter battery backup time is not rocket science. All you need to know are a few parameters and you are good to go. The UPS backup time depends on the power consumption of the UPS, the power of the load, and the battery capacity. 

In general, you can expect your inverter battery to last anywhere around 5 to 10 hours when it is fully charged. However, you can easily calculate the accurate battery backup time with a simple formula or use a battery backup calculator

How to Calculate Inverter Battery Backup Time?

You can use the following simple formula:

Backup Time (in hours) = Battery Capacity (in Ah) X Input voltage (V) / Total Load (in Watts)

Let us assume that you have an inverter battery with 150 Ah of capacity and 12 V of input voltage. You want 3 tube lights, 2 fans, and 1 Wi-Fi router to run on that battery. So, what will be your inverter battery backup time, and how long will your appliances run in this specific case? Let’s find out. 

Taking your inputs into consideration, you can calculate your total load, like:

  • 3 tube lights = 40 x 3 = 120 Watts
  • 2 fans = 75 x 2 = 150 Watts
  • 1 Wi-Fi router = 1×20 Watts = 20 Watts

So, the total load in your case is 120 + 150 + 20 = 290 Watts.

Now, let us apply all these values in the above-said battery backup time formula. 

Backup Time (in hours) = 150 x 12 / 290 = 6.2

So, your inverter battery will last around 6.2 hours to keep your needed appliances running. 

Battery Capacity and Inverter Backup Time:

Does the backup time depend on the capacity of the battery? Of course, it does!

Let us keep all the values same other than the battery capacity. Now, let us figure out the inverter backup time for both small and large battery capacities. Using a UPS backup calculator can also help. 

If the battery capacity is 110Ah:

  • Backup Time (in hours) = 110 x 12 / 290 = 4.5 hours

In this case, you will get an inverter backup of only 4.5 hours.

If the battery capacity is 220Ah:

  • Backup Time (in hours) = 220 x 12 / 290 = 9.1 hours

In this scenario, you will get an inverter backup of nearly 9.1 hours. 

So, you can safely assume that your battery’s capacity plays a vital role in your inverter backup. Or the higher the battery capacity, the greater will be the inverter backup time.  

The above calculation is perfect on paper. But in a real-time scenario, the inverter’s efficiency plays a vital role in its backup time. The better the inverter efficiency, the more the backup time. 

How to Improve Your Inverter Battery’s Backup Time?

To ensure long-lasting battery backup time during power outages, follow the below steps:

  1. Decreasing the load will directly improve the backup time. Less load means fewer appliances and more backup time.
  2. You can invest in quality products from a reputed company like Genus. Genus manufactures high-quality products with high efficiency, resulting in fewer power losses and more backup time. Genus inverters come with improved battery life as they prevent the battery from overcharging. 
  3. Use the right charging setting of the battery. 

Also Read: How to Accurately Size a Battery for Solar Energy?

Final Thoughts:

Hopefully, this blog has made UPS battery backup calculation easy. Isn’t it much easier than you thought? So, when it comes to assessing your inverter backup time, you need not go by anyone else’s words. You can figure it out yourself with the simple formula discussed here. 

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