22 Years' Battery Customization

Calculating Battery Life

Mar 24, 2023   Pageview:197

Today most devices we use to tell the life or run-time of a battery in different ways. From our smartphones to windows laptops and even other smart battery applications, almost everything can tell the remaining expected time for which the battery will be providing you power.

Do you know how to calculate the battery life, and what are the different methods? The method you select depends on the data you have, and the most effective way to calculate your battery's life is by using amp hours or power consumption.

Calculating Battery Life Amp Hours

The most common way of calculating the battery life is by using amp hours. So, here we will discuss how you can calculate your battery's run-time or remaining life. For this calculation, we will consider the example of a 12-volt battery.

All the data you need.

The first thing you know is that you are using a 12-volt battery. Apart from it, you need some other data, which includes the amps of a battery. Additionally, you need the watts you are getting from your battery along with the time you use the battery in hours. You can put these two values in the formula to get the battery life value.

How to calculate your battery’s life using amp hours.

By taking all the values, we can calculate your battery's amp hours, which will be its run time. Remember that no battery system is 100% efficient, so first, we will calculate the watt hours of your battery considering its efficiency. The product of watts and hours divided by the efficiency percentage will give you the watts hours.

Next, you can divide the watt-hours by the battery voltage, giving you the amp-hour value for the system.

Amp hours= watt hours/volts

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What to do if you are not using a 12-volt battery.

Say that you are not using the same 12-volt battery, which is of some different value, like 6 or 18 or even some other. While everything else stays the same, the voltage value will become different when calculating the amp hours for your battery.

Similarly, the efficiency of your system is a vital component of this calculation. If you calculate the value considering 100% efficiency, the practical battery life will never meet the theoretical value.

Calculating Battery Life with Inverter

Batteries are used with inverters and UPS to provide a power backup for homes and offices. While some inverters are smart enough to give the remaining battery life, not all are smart. However, in most cases, an inverter provides enough information that you can take and calculate the remaining battery life yourself.

The formula to apply.

Here is the formula that you will need to calculate your battery life:

Battery life (hours) = battery capacity (amp hours) * voltage / load (watts)

It simplifies to hours = amp hours*volts / watts.

So, with this formula, one clear thing is that you will need to know the battery voltage, the total load you are putting on the system, and also the amp hours shown by your inverter.

A real-life example of calculating battery life with the inverter.

Say that you are using 1 tube light that consumes 40 watts total, one fan that consumes 80 watts, and a Wi-Fi router is also running on the inverter that takes 20 watts total.

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Adding all the load values gives you a total load of 140 watts. For instance, the battery amp hour value is 150, and you use a 12-volt battery. Then the implementation of the formula above will be:

Hours = 150*12/140

Hours =12.8

The changing values that you must consider.

When calculating the battery life with your inverter, it is essential to be careful about the changing values. In most cases, the voltage or capacity varies. It is because some UPS systems take 2 12-volt batteries, so the total voltage becomes 24. Similarly, depending on the size of your battery, you may get 110-220 am hour capacity.

The wattage of things you are running on the system can also change. Lastly, the efficiency of the system changes according to different conditions.

Calculating Battery Life Power Consumption

Another way you can calculate the remaining battery life is by considering the power consumption. The whole system's efficiency is effective in the same way as in other cases, but the formula is a bit different.

Calculating Battery Life Using Power Consumption

To calculate the battery life, you first need to know the capacity of your battery, usually in amp hours. This value is found on the battery label.

Next, you need to check the consumption of all the devices using a battery. For instance, if 2 bulbs and 1 fan are running, the total consumption will be their average current draw added.

Lastly, you must consider the discharge safety of your battery. The value gives a percentage of battery capacity that is never used. For instance, the discharge safety percentage of a LiPo battery is 20% means that you must never discharge it below 20% of charging still left.

Once you have all these values, you can apply the gives formula:

Capacity / Total consumption * (1-Discharge safety)

This formula gives you the theoretical value of battery life. However, when you calculate a real-life example, the efficiency of your system will also be included with some other factors like:

Awake time

Sleep time

Power consumption during sleep mode

Self-discharge when not in use, etc.

The above values can differ depending on different circumstances, including battery efficiency, environment, system conditions, load efficiency, etc. That is why the practical battery life is always short of the theoretical value we calculate.

Conclusion

As you hover the mouse cursor over the batter icon on a windows laptop, it shows the percentage and the remaining time estimate for which your battery can keep the laptop running. That is the battery life, and calculating it gives a general idea about how long the battery can keep your device running. While it is a calculated estimate, it can give you an idea about how long you can keep the device running.

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