How Many Batteries Needed for a 2000W Inverter

In this article, let’s discuss how many batteries you’ll need for a 2000W inverter.

Let’s talk about finding the right inverter battery size, how long it’ll last, and the best options to go for between pure sine wave and modified sine wave inverters.


You’ll learn all the important things to consider when determining battery requirements for different inverters.

Let’s get right into it!

Battery Requirements When Working With Inverters

The battery requirements when working with inverters depend on the power requirements of your appliances, the backup time you want for the appliances you intend to run, and the efficiency of the inverter you’re using.

How long a battery can provide a set amount of power is referred to as its BATTERY CAPACITY, and it is expressed in Ah.

Let’s quickly illustrate how to discover the ideal battery capacity using the power ratings of some appliances below.

70W Television

A 12V battery with 33.3Ah battery capacity or more is needed to run a 70W television, and A 24V battery with 16.7Ah battery capacity or more is needed to run a 70W television.

  1. Decide is the AMOUNT OF TIME you want for the TV to run on the battery. Assume running a 70W television for 5hours
  2. Appliance requirement = 70 x 5 = 350Wh (Watt-hours)
  3. Consider the EFFICIENCY OF THE INVERTER. Assuming a 90% efficiency, the battery has to supply 350Wh/ 0.9 = ~400Wh of power

You need a battery that can provide 400Wh of power. Let’s try to obtain the corresponding value of the battery capacity in Ah (Ampere-hours).

This value depends on the voltage of the battery you’ll be using. Batteries are typically sold in 12V, 24V, 48V, or 120V. However, 12V and 24V batteries are most commonly used for this purpose.


Since Power = Voltage x Current, then, Current = Power / Voltage

For a 12V battery, 400Wh/12V = 33.3Ah.
For a 24V battery, 400Wh/24V = 16.7Ah.

1000W Coffee Machine

A 12V battery with 470Ah battery capacity is needed to run a 1000W coffee machine, and A 24V battery with 230Ah battery capacity is needed to run a 1000W coffee machine.

We arrived at these values in a similar procedure. Let’s have a go at it again!
A 1000W coffee machine that you intend to run for 5hours needs 1000W X 5hours = 5000Wh of power from the battery.

An efficiency of 90% corresponds to 5000Wh/0.9 = ~5600Wh of power from the batteries
For a 12V battery, 5600Wh/12 = ~470Ah.
For a 24V battery, 5600Wh/24 = ~230Ah.

How to Find the Right Inverter Battery Size

You need to know the following things to find the right inverter battery size:

  • Inverter efficiency: Inverter efficiency is a measure of the input power that gets converted to output power.
  • Inverters often have efficiencies ranging from 80% to 90%. It is calculated as output/input x 100.
  • Power requirements: This is the total wattage of the appliances you want to run the inverter with.
  • Runtime: This is how long you want the appliances to run on the inverter and battery.
  • Actual battery capacity and voltage: This is how much power capacity and voltage the battery delivers when in use as opposed to the stated rating from the manufacturer (Nominal capacity and voltage).

We’ll put all these together to help you find the right inverter battery size in the illustration below.

How Long Will a 12V Battery Last with a 2000W Inverter

A 12V battery running with a 2000W inverter at 90% efficiency can run for about 8mins depending on the actual battery capacity.

The inverter demands 2000W from the battery. At 90% efficiency, it means it actually draws about 2000/0.9 = 2222W from the batteries. But, as the battery begins to work, the voltage drops from 12V to about 10.5V or lesser for some batteries.

Therefore, this drop in voltage must be considered when calculating the time. Different manufacturers provide this information in the constant discharge power tables of their batteries. You should factor it in when trying to know how long your battery will last.

Pure Sine Wave Vs Modified Sine Wave Inverter: Which to Use

You should use a pure sine wave inverter if you want to power SENSITIVE ELECTRICAL EQUIPMENT that prefers to RUN STRICTLY ON “CLEANER” AND BETTER CURRENT. A pure sine wave inverter is also ideal if you have a reasonably high budget for powering these kinds of appliances.

Examples of appliances best suited for pure sine wave inverters include laptops, specialized medical equipment, laser printers, refrigerators, etc.

You should use a modified sine wave inverter if you want to power GENERAL EQUIPMENT AND APPLIANCES THAT ARE LESS SENSITIVE. It is also ideal if you have a relatively low budget.
Examples of appliances best suited for modified sine wave inverters include phone chargers, electric heaters, air conditioners, etc.

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