How Much Solar Do You Need to Power an Air Conditioner?

Air conditioners are important in every household because they help you keep your home cool in summer. Even if you live in a place where winters are mild, an air conditioner can be used in winter too. If you don’t have access to electricity or if your electricity supply is unreliable, an off-grid air conditioner may be your best option.

An air conditioner is typically a high-wattage appliance however they are options that allow a more sustainable of running an air conditioner off solar power. 

How Much Solar Do You Need to Power an Air Conditioner?

Solar Power for a 1000-Watt Air Conditioner

The most important thing when choosing an air conditioner is to make sure that it will cool down your space without using too much energy. If you plan on using solar panels and batteries to power your home, then you’ll want to use as little electricity as possible so that your batteries last longer.

A typical 10,000 BTU air conditioner is enough for a small room or even a cabin. This air conditioner will have a wattage of around 1000 watts.

To run a 10,000 BTU air conditioner for an hour you will need a 500-watt solar panel and 24V 200Ah Lithium Battery. You will also need an inverter rated at least 1100 Watts. 

Let’s talk you through how we got to this:

Air conditioner Watt-Hour Energy Requirement 

The amount of energy used by an appliance is measured in watt-hours. The time it takes to use that appliance dictates how much energy it uses. This is calculated by multiplying the wattage of your air conditioner by the number of hours you will run it.

Watt-Hours = Watts X Hours 

If you want to use an air conditioner for 1 hour, you will need 1000 Wh

This number will help us calculate the number of solar panels required and how big of the battery bank is needed to support it.  

What Size Solar Panel for an Air conditioner

The size of the solar array is determined by the size of the system’s area, altitude, and distance from the equator. If you are in an area that receives around 4 hours of sunlight daily, you will divide the total Watt-hour requirement by this number.

1000Wh/4 = 250 Watts

During summer you can get more than 4 hours of sunlight in the course of a day. We usually recommend you go higher on the solar panel size. In this case, take a 500-watt solar panel might be more than adequate. As long as there is no prolonged overcast.  The extra power will be stored in the battery.

Also, remember we are doing this through an inverter and battery. You also need a battery that supports these power requirements. 

What Size Battery to Power an Air conditioner?

From the example above we’ve seen, we’ll need around 1000 Wh in order to run an air conditioner for 1 hour a day. In order to get the size of the battery, you would need to run the air conditioner you will get the number of amps the appliance is drawing. 

To get the number of amps you divide the Watts by the voltage of the system. 

For a 12v system:

1000W/12= 83.3 amps 

For a 24v system 

1800W/24= 41.6 amps

 Amp-hours is 1-amp of power expended over one hour. This can tell you if a battery can work for the intended use or not. 

Batteries are not designed to be depleted over a short period of time. Most solar batteries are labeled deep cycle and are intended to be used over a 20-hour period max.  But with LiFePo4 batteries, it is possible to stretch this limit as they have a 1C C rating which means you can discharge the whole battery at once. This is not recommended however but a 50% discharge in one hour is possible. 

So if we were to use a 24v 200Ah LiFePO4 battery bank it can support the 41 amps drawn from the air conditioner for every. This battery can last up to 5 hours without recharging this air conditioner.  With Solar panels, you can add other appliances like a small TV and charge your devices.

Inverter for the 1000-watt Air conditioner

You will need an inverter in order to convert the DC power from the Air conditioner to AC power. Because of inefficiencies from Inverters, it is a must to oversize the system. You will need an Inverter that is rated at least 1100 watts. 

Conclusion 

Solar power is a convenient and clean way to run an air conditioner during the summer. As the day heats up you can use the sun’s power to cool down. While an air conditioner may require more to run than most appliances you can get a low-wattage air conditioner for a smaller space that will not need as much power. 

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