How Fast Will a Power Inverter Drain Battery?

When considering buying an inverter, one of the first questions you probably have is how long it takes to drain the battery.

Answering this fundamental question will ensure you are buying the right size for your needs and know what to do with your inverter and for how long.

Several things can affect the battery’s ability to power devices and appliances, and the characteristics of the inverter can be one of them. We want the battery life of our devices to be as long as possible.

This article explains how to get the most out of your battery life and how fast your battery runs out.

Power Inverter Characteristics that Affect Battery Life 

So how fast will an inverter drain the battery?

A better way to ask this question is how long you want the upload to take. By asking this question, you can perform specific calculations that can help you determine the ideal size for your battery bank.

The run time of your device also depends on the power consumption, which is usually measured in watts, and the capacity of the battery.

It is also important to note that inverter inefficiency and incorrect battery wiring during installation can significantly reduce the operating time of your device, so be sure to follow the advice of an expert when installing.

Units for Measuring Electricity Features

A good way to know the watt reading is to multiply the volts by amps. The capacity of your battery can also be expressed by the number of amps and how many hours your battery lasts. This is known as amp-hours or A.H.

Every 100 watts of a 12 volt inverter system requires about 10 amps of DC from the battery. Meanwhile, a 24 volt inverter system requires 10 amps of DC from a battery for every 200 watts. It is important to remember these numbers, because the efficiency of the battery depends on them.

You can see how long your battery will last by estimating the total watts of the charge. Also look at the type plate of the electrical input of a device and add up your total requirement. This will give you an idea of ​​how much energy your appliance may be consuming.

However, there are some loads that are not constant, so it’s important that you get estimates. Take, for example, a refrigerator that runs on a 750-watt compressor. If it works 1/3 of the time, it would work about 250 watts per hour.

The size of the battery bank can be calculated once the run time and charge have been determined. To do this, you first need to divide your watt load by 10. This is if your device works on a 12 volt system. If it works with a 24 volt system, divide it by 20.

Meanwhile, the amount of time your inverter takes to run your devices depends on the power capacity of your battery.

Use this formula to find out how long your battery will last:

(10 x [Battery Capacity] / [Load]) / 2

However, you need to know the wattage of your device and the reserve capacity of the battery before you can enter the numbers into the formula. So, for example, if your battery has 100 amp-hours and you’re going to use it in a laptop that uses only 45 watts, you’ll get about 11 hours of run time from your battery.

The formula becomes as follows:

(10 x [100 AH] / [45 Watts]) / 2 = 11.11 hour

However, you should be careful when dealing with your investor, even if you already know the numbers. This is because, for example, if you are going to force a 45 watt load to run for 11 hours on a 100 AH battery; Chances are there isn’t enough power left to jack up the starter motor.

This also means that devices with greater load, such as desktops, televisions and other electronic devices, drain the battery faster.

How Fast Will a Power Inverter Drain Battery?

If you’re thinking of buying a power inverter one of the first questions that you probably have is how long will it take to drain you battery.

Answering this fundamental question will ensure that you purchase the correct size for your needs, and that will know what you can run from your power inverter, and for how long.

Different things can influence the ability of the battery to power up gadgets and appliances, and the power inverter’s features can be one of them. We would want the battery life of our devices to be extended as long as we possibly could.

This article will guide you more on how to make the most of your battery life, and how fast it will drain them.

Power Inverter Characteristics that Affect Battery Life

So how fast will a power inverter drain your battery?

A better way of asking this question would be how long would you want your load to run. By asking this question, you’re able to make specific calculations that can help you determine the ideal size of your battery bank.

The amount of time that your appliance will operate will also depend on its power consumption that’s usually measured in watts and battery capacity.

It’s also important to note that inverter inefficiency and improper wiring of the battery during installation can greatly reduce your appliance’s running time, so make sure you are taking expert advice when installing.

Units for Measuring Electricity Features

One good way of knowing the watt measurement is by multiplying volts by amps. Your battery’s capacity can also be expressed by the number of amps and how many hours your battery will last. This is referred to as the Amp-Hours or A.H. capacity.

Every 100 watts of a 12-volt inverter system needs around 10 DC amps from its battery. Meanwhile, a 24-volt inverter system needs a battery’s 10 DC Amps for every 200 watts. These figures are important to remember because these are where your battery’s efficiency depends on.

You can know how long your battery will last if you estimate the load’s total watts. Also look at an appliance’s input electrical nameplate and add up its total requirement. This gives you a hint on how much power your appliance can take.

However, there are a few loads that aren’t constant, which is why it is important for them to get estimations. Take for example a refrigerator that’s powered by a 750-watt compressor. If it runs 1/3 of the time, then it would be running around 250 watts per hour.

The size of the battery bank can then be calculated once the running time and load are established. To do this, you first need to divide its watts load by 10. This is if your appliance runs on a 12-volt system. If it runs on a 24-volt system then divide it by 20.

Meanwhile, the amount of time that you use your power inverter to run your appliances will depend on your battery’s power capacity.

Use this formula to know how long your battery will last:

(10 x [Battery Capacity] / [Load]) / 2

However, you need to know your appliance’s wattage and battery’s reserve capacity before you can input the figures in the formula. So, for example, if your battery has a 100 amp hour capacity and you’re going to use it on a laptop that uses only 45 watts, then you’re going to get around 11 hours of working time from your battery.

The formula then becomes like this:

(10 x [100 AH] / [45 Watts]) / 2 = 11.11 hour

However, you still need to be cautious when dealing with your inverter even if you already know the figures. This is because if you’re going to, let’s say, force a 45-watt load to run for 11 hours in a 100 AH battery; there’s a huge likelihood that there won’t be enough power left to beef up the starter motor.

This also means that appliances with bigger loads such as desktop computers, televisions, and other electronics will drain your battery faster.

Working Example

To better understand the capabilities of our car batteries and how these inverters will definitely affect their lifespan, we have a real-life case study that focuses on all this in numbers.

For this study, let’s see how long the starter battery of an average car engine, rated at 60 Ah, or amp-hours, can run a television with an average power of 100 watts. The car’s engine battery is also PW150 rated.

This means that the load falls within the maximum power of the PROwatt inverter. As a result, the inverter will not be a limiting factor for the useful life of the TV. This is a common scenario for those with RVs, as well as truck drivers who want better entertainment to accompany them on the road.

Taking the numbers into account, we have 10 multiplied by 60 Ah multiplied by 100 W.

This means that the TV can run for up to 6 hours before the battery is completely discharged, and for a more comfortable viewing comfort and to ensure that the car can still be started, 3 hours runtime to half battery point.

Of course you don’t want the battery of your car to drain, so that it does not continue to work.

Some Tips Worth Keeping in Mind

Engine starter batteries shall not have a discharge rate lower than 90% of the others, and for deep cycle marine batteries it shall not be lower than 50%. This is because any rate lower than this would shorten battery life, and many battery manufacturers prescribe this as well.

In the case of the PROwatt250, it comes with a lighter plug that allows for an easier charging connection, especially between the little ones. However, a direct connection is required if you want to charge 100W or more at the battery terminals. This helps reduce the amount of voltage lost on long, thin battery cables. Ultimately, less voltage drop means a shorter time to get the entire system up and running.

If you want to use power tools for purposes other than domestic use, or for 200 W loads for applications longer than one hour, an auxiliary battery may be required to power the inverter.

In addition, it must be deep cycle and can work according to runtime expectations, with the engine off. Most of the available deep cycle batteries are typically 27.4d and 8d which have 90Ah, 150Ah and 220Ah respectively.

Finally, the alternator should not be connected to the auxiliary battery through an isolator module, as this will cause the inverter to discharge the engine’s starter battery even when it is turned off, potentially wasting a lot of electricity.

Knowing how long it takes for an inverter to drain a battery is one of the top lists to know when buying one. Now you may need to know which one to choose between modified sine wave inverters or pure sine wave inverters.

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