It might be challenging to figure out how to determine the right inverter size for your requirements, particularly if you don’t know how an inverter works or how much electricity you need to generate.

Although inverters are valuable tools, you may still need to know more about other pieces of technology in order to produce a precise estimate or resolve a problem.

Some typical queries are as follows:

  • Can I use an inverter to power a freezer?
  • What can I use a 300 watt inverter for?
  • What kind of inverter do I need to operate a microwave?

Of course, there are more.

However, by using our inverter size calculator, you can determine the proper size regardless of whether you need a large or small inverter.

A power inverter uses how much electricity, first? Two requirements must be met by an inverter: peak or surge power and average or regular power.

  • Surge The inverter’s surge is its maximum power capacity, which it typically only offers for a brief period of time (often no more than a second, unless otherwise indicated in the inverter’s specs). Some appliances need a substantially bigger start-up surge than they do while they are operating, especially those with electric motors. The most prevalent examples are pumps, compressors, and air conditioners, although freezers and refrigerators are also often used devices (compressors). To avoid prematurely burning out the inverter, choose an inverter with a continuous rating that can withstand the surge rating of your appliance. As inverters prefer not to function in surge mode, unless the manufacturer claims to have a longer surge duration than typical, don’t depend on the inverter’s surge to start your equipment.
  • Typical What the inverter must consistently deliver is typical. This rating is ongoing. Typically, this is considerably less than the surge. For instance, this is the amount of power needed to operate the microwave or a refrigerator after the first few seconds it takes for the motor to start up, or the sum of all loads. (See our comment on name tag ratings and/or appliance power at the end of this section.)

What Size Inverter Do I Require?

Simply sum up the required wattages of the devices you need to power to get the right inverter size for your requirements.

The right size will be determined by a measurement based on the required average and surge power, regardless of whether you’re searching for the optimum inverter size for your home or something as simple as an inverter to power your TV.

In order to avoid damaging your inverter, you’ll need to provide extra surge power if your equipment needs it to start up.

Calculator for inverter watts to amps: Finally, in order to calculate how much battery drain your inverter would need, it could be essential to determine the necessary amps.

This may be helpful for calculating the required voltages or for determining the appropriate battery size for your inverter (which you can figure out using our helpful instructions).

To calculate the size, use the formula below:

Volts * Amps = watts or Watts / Volts = amps

1250-watt example:

1250 / 120 Vac = 10.41 amps AC (typical number found on equipment) or 1250 / 12 Vdc = 104.1 amps DC (battery drain per hour)

Here’s an illustration:

To start, you must decide which devices and for how long you need electricity during a power outage.

Here is a succinct illustration (watt needs change):

  • Lights: 200 watts or such
  • Refrigerator: About 1000 watts
  • Radio: 50 watts or less
  • Heater: around 1000 watts

2250 watts are the total amount required.

Let’s give the heater and refrigerator a beginning power allowance of double the constant watts.

2250 * 2 = 4500 watts

Check out this handy calculator to obtain an estimated total wattage for all the devices your inverter will be powering.

You may save time and get an accurate measurement with this practical measuring equipment.

Next, choose an inverter.

You will want a power inverter with a 4500 watt handling capacity for this example.

The real continuous power need is 2250, but you must account for the start-up when designing an inverter so that it can manage it.

Decide how long you want to run 2250 watts, which is the next step.

Let’s assume you want to run these devices for eight hours.

Well, this may be challenging since refrigerators and heaters operate erratically.

Let’s suppose that all of the appliances will operate for 40% of the allotted time, or 3.2 hours, in total.

Because batteries are rated in DC amp hours rather than AC watts, we must convert the two units.

You must divide the AC watts by the DC voltage to convert AC watts to DC amps per hour (usually 12v or 24volts).

As it is the most typical, let’s utilize 12 volts.

187.50 DC amps per hour from 2250 watts at 12 volts

Your current hourly power demand is 187.50.

You have now calculated your power demand per hour to be 187.50, and you need to multiply that number by the entire number of runtime hours, which in our case is 3.2.

A DC amps per hour of 187.50 600 DC amps in 3.2 hours

Because you’re using an inverter, you need to figure out the loss in power conversion, which is often approximately 5%.

(600 DC amps * 5%) plus (600 DC amps) equals 630 DC amps/hour (This is how much power you need in an eight-hour period running your appliances 40 percent of the time.)

Fourth, we may choose a battery source now that you are aware that your overall power needs total 630 DC amps.

Most common deep cycle batteries have a voltage of six to twelve volts.

I’ll use each voltage to provide you with two examples.

Example using a 12-volt battery: If you use a 12-volt battery with a 100 DC amp rating, you will need six or seven batteries connected in parallel (I will explain parallel vs. series later).

630 DC amps / 100 DC amp battery = 6.3 batteries

Six-volt battery example: If you use a six-volt battery with a capacity of 200 DC amps, you will need six batteries connected in series and parallel. batteries: 3.15 x 2 = 6.3 I didn’t err, I assure you. In order to get 12 volts while using six-volt batteries, you must link them in series. The 12-volt battery bank is then made by paralleling each series pair of six volts.

What Distinguishes Running Batteries In Series From Parallel?

Amps are increased when batteries are connected in parallel.

Voltage is raised by series-connecting batteries.

Limiting your parallel strings is preferable in the world of batteries.

Your power system will benefit more from it.

Because of the quantity of batteries needed in this example, I advise using six-volt batteries.

How are these batteries recharged? When you have access to city electricity, a charger is required to recharge the batteries.

The majority of deep cycle batteries need a “smart” charger to prevent harm to the batteries from the charger.

In this case, you will want a charger that is at least 40 amps or larger.

The rate of charging increases with charger size.

Because the system we just mentioned is a 12-volt system, be sure your charger is for 12-volt batteries.

Cables are also required.

To handle the 4500 watts of starting power in this scenario, a 4 AWT (0000) cable is needed.

It’s a large cable.

An inline fuse could be something else to think about.

For this scenario, a 500 amp is ideal.

You divide your AC watts (startup) by your DC voltage to get the fuse size.

4500 watts / 12 vdc = 375 amps

You would need a fuse of at least 375 amps.

Just in case you were to use the 5000-watt inverter to its maximum, I advise a 500 amp backup.

This is only a small illustration.

Your system may be set up in a variety of ways.

You may make use of wind, sun, etc.

In light of this, how big of an inverter do I need? Keep in mind that a variety of variables influence the required wattage.

Although the method for calculating this can seem straightforward, you also need to take into account power loss, other factors involving your electrical equipment, surge power, and other factors.

Next, determine the size of your batteries, whether paralleling or seriesing them is preferable, the kind of charger to use, and how to connect them.

We’ve taken the initial steps in what might seem like a difficult process of choosing the proper equipment.

What Size Inverter Do I Need? Videos Suggestions From Youtube

What Size Inverter Do I Need? – How to Choose the Right Size Inverter | Accelerate Auto Electrics – Accelerate Off-Grid Touring
What is a Power Inverter and which inverter do I need? What does a power inverter do? – Wagan Tech
How To Size Your Inverter: The 4-step approach – Solar Solution

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Written by Bob Matsuoka
Bob Matsuoka is a blogger and founder of RVing Beginner blog. He has been blogging for over five years, writing about his own family’s RV adventures, tips for people who are interested in buying an RV or taking their family on an adventure by RV.