How Long Will a 1500 Watt Inverter Run?

Determining the runtime of an inverter is essential for anyone relying on portable power sources. In this blog, we will discuss how long a 1500 watt inverter runs and the key considerations that influence its operation.

How Long Will a 1500 Watt Inverter Run?

Connected to a 120V battery, a 1500 watt inverter with a 200 Amps hour rating can operate for an impressive 16 hours. Even at full load, the inverter can provide power for a substantial 80 minutes when connected to a 1500 Amps 120V battery.

Note that the type of battery employed in a 1500 watt inverter also plays a crucial role in determining how long a 1500 watt inverter runs. While SLM batteries and AGM batteries are commonly used in households, it is highly recommended to opt for a battery with deep discharge capability when choosing an inverter. Moreover, lithium batteries can have different usage capabilities, with some allowing up to 100% usage depending on the manufacturer and brand of the battery.

Appliances that a 1500W Inverter Can Run

Other than the type of batteries, what matters is the workload on an inverter. In fact, when a 1500 watt inverter is connected to a 500 watt load, it has the potential to draw up to 50 Amps. Inverter loses some energy as it operates, so possibly for a 1500W inverter let us assume it can take up a workload of around 1200 watts only.

Let us now divide this wattage into devices that we would be powering with it.

• 100-watt ceiling fan
• 100-watt laptop
• 20-watt cellphone
• 40-watt television
• 800-watt fridge

Supposedly, these devices can altogether run, taking up slightly less than 1200 watts. So, the number, type, and wattage of devices also affect how long a 1500-watt inverter will run and the appliances it can power.

Also Read: Can a 1500-Watt Inverter Run a Microwave?

What is the Battery Size for 1500 Watt Inverter?

To calculate the battery size for 1500 watt inverter, take a look below:

1. Determine Amperage that the Iinverter would Draw

For this calculation, we need to divide the watt rating by the voltage.

For example, if we have a 12V system of 1500 watts,

Amperage = 1500 / 12 = 125 Amps

So, for a 12-volt system, it is crucial to have a battery capable of delivering a reliable and secure current of 125 amps per hour when utilizing 1500 watts of power.

Suppose we have a 24V system, following the same rule.

Amperage = 1500/24 = 62.5 Amps

So, we need a battery size with a capacity of 62.5 amps to maintain its performance.

2. Determine Number of Ampere hours or Capacity

Choosing a 12V system would require you to have a substantial battery life. Deep cycle batteries designed for long-term use have a discharge rate of 0.2C or 20% per hour. To sustain a draw of 125 amps at a voltage of 12V, you would require approximately 625Ah.

To power a 24V system effectively, it is essential to equip it with a high-capacity lithium battery, such as a 315Ah or 300Ah 24V battery.

3. Determine Battery Size Based on Duration of Your Appliance Usage

The size of the battery you require depends on the duration of your appliance usage. A 1200-watt electric kettle, for instance, would require a 1500-watt inverter. However, you would only be able to use the kettle for a brief period of time.

Here is a table based on rough assumptions for a 24V system; you can calculate the same for your inverter with its specifications.

Also Read: How Long Can Tesla Powerwall Run AC?

How Many Batteries for 1500-Watt Inverter?

As discussed in the table above, if we are drawing 30 amps per hour, at a voltage of 24V, this would require approximately 300Ah, and for that, you would need 6 batteries (110 Ah 12V).

Let us find out how many batteries for 1500 watt inverter are required. To calculate this, you must be aware of how much power your system will be drawing every day.

Step 1: Calculate Your Daily Power Consumption

Power consumption is expressed in Watt-hours (Wh). You have to add the power consumption of every appliance you use. 

Daily power consumption = wattage rating of device × no. of hours

For example, 1 light bulb consumes 100W, and we are using 4 units for 5 hours a day.

Thus, 4 × 100W × 5 hours = 2000Wh/day.

Step 2: Calculate Backup Power

For this, multiply daily consumption by the number of days.

Backup Power = daily power consumption × no. of days

Backup for 2 days = 2000Wh/day × 2 days = 4000Wh.

Step 3: Find Depth of Discharge

To maximize the service life of batteries, it is essential to minimize the discharge frequency of the battery, irrespective of their type or cost. So, determine a calculated maximum depth of discharge and then divide days of backup power by it. Choose the factors that result in a lower average temperature in which the batteries are going to work. Then multiply this number by the maximum depth of discharge.

For example, 50% DoD = 4000/50% = 4000 / 0.5 = 8000Wh

Step 4: Calculate Minimum Capacity of Your Battery

For connecting batteries, calculate the minimum capacity of your battery by dividing the power by the desired voltage.

Therefore, 8000/24V = 333.33 Ah is the minimum capacity of your battery bank.

Step 5: Identify How Many Batteries You Need

Let’s suppose, we have 110Ah (12V) deep-cycle batteries for a 330Ah 24V battery bank:

For 24 V battery bank, number of batteries (12V) = {330/110} × 2 = 3 × 2 = 6 batteries

For the 48V system, the number of batteries (12 V)= {330/110 } × 4 = 12 batteries.

Note: In your calculations for the number of batteries and their size, you need to consider the battery’s age, power loss, and temperature factors, along with the overall efficiency of the system.

Also See: How Many Batteries for 1000 Watt Solar System?

Can I Use a 1500-Watt Inverter With a 100 Ah Battery?

For a 1500-watt inverter, you will need approximately 6 units of 100 Ah battery (12 V) to run certain appliances like a fridge, air conditioner, coffee machine, electric kettle, etc.

If you wish to run appliances that use relatively less power like laptops, lights, TV, etc. then in that case, an inverter with less voltage is preferred.

Cross-Reference: A Complete Guide About Solar Panel Installation. Step by Step Procedure with Calculation & Diagrams

We have examined how several factors determine the battery size and the runtime of a 1500-watt inverter. We have also addressed whether a 1500-watt inverter can be paired with a 100 Ah battery. For more information on inverters and their batteries, stay tuned.