Generally speaking, a central air conditioner will consume between 3000 and 3500 watts per hour. Beyond that, they draw 3 – 4 times more power each time the compressor starts.
They are generally more suited to running off a fully installed solar setup with substantial battery capacity.
It is difficult to run air cons overnight due to the high power consumption and need for a powerful battery installation.
Smaller units (in an RV) can be run successfully, although briefly, with portable solar-powered generators.
Air conditioners and fridge-freezers are some of the most difficult appliances to run off a solar-powered generator. The power they consume is generally higher than most other appliances.
Types Of Solar-Powered Generators
There are three broad categories of solar-powered generators:
- Solar power permanently installed backup generators.
- Partially portable solar-powered generators.
- Fully portable solar-powered camping generators.
Solar Power Permanently Installed Backup Generators
Solar generators permanently installed at a location can be a partial or full backup to the main utility-generated electrical power supply.
These devices will be activated (either automatically or manually), and they will generate an alternate power source that acts as a substitute for the conventional utility power supply.
As a full backup, they are sized to replace all the power at the premises. This means that they can provide the total power needs of the building.
Partially Portable Solar Powered Generators
This category can produce high power output and, although heavy, can be moved around.
Which means they can be used offsite (albeit in a controlled environment). They can also be used as an RV’s power supply, meaning the RV does not need to be connected to a mains power supply.
Fully Portable Solar Powered Camping Generators
These small, portable solar-powered generators are compact and lightweight.
Examples of fully portable solar-powered generators are the Bluetti AC60 or Jackery 500, which produce around 0.5kW and only weigh about 13 lbs. (6.04 kg).
These devices can power small electrical appliances such as lights, cooler boxes, and phone chargers but not air conditioners.
They make an excellent companion when low levels of virtually silent portable electrical power are needed.
Solar Powered Generator Power Outputs
Along with the different uses for solar power generators, there is also a wide selection of power levels that are produced.
These range from 0.5kW at the low end to 25kW for large solar generators linked together.
Examples of the varying levels of solar power generators are listed below.
|Solar Generator||Inverter Power||Surge Power||Battery Power||Run AC|
|Ecoflow Delta Max||2,400W||5,000W||2,400Wh||❌|
|Ecoflow Delta Pro||3,600W||7,200W||3,600Wh||✅|
|Bluetti AC300 Extended||6,000W||12,000W||24,576Wh||✅|
|Ecoflow Delta Pro Extended||7,200W||14,400W||25,000Wh||✅|
Powering Air Conditioners With Solar Systems
Air conditioners are one of the most commonly used electrical home appliances in America and account for 12% of the power used in households across the US. The US Department Of Energy (DOE) states that air conditioners account for 6% of ALL electricity consumed in America.
Even though air conditioners consume large amounts of electricity, running one off a solar generator is possible.
The issues that you will need to consider as listed below.
- Air-conditioners are high-consumption appliances and will require large batteries to run at night or in bad weather.
- They require a “surge” current to start the compressor that can be three times more than the normal “running” consumption, which will dictate the size of the solar generator used.
There are three categories of household air conditioners used in private homes.
AC Solar Air Conditioners
AC (alternating current) units are the traditional choice for household air conditioners. The primary reason for this is that the power supply from the utilities is AC, and there has yet to be an incentive to explore other technologies.
The problem with AC air conditioners is that they are not an efficient electrical consumer.
The compressor is the component that uses the most energy in an air conditioner. The compressor’s motor generally runs on a direct current (DC).
This means the AC connecting to the main power supply passes through a rectifier that converts it to DC.
An AC air conditioner that runs off a solar system may convert the current twice (the DC from the solar panels is converted to AC and is then passed through the rectifier where it is covered back DC.
There are a few disadvantages to running AC Solar Air Conditioners of a solar system:
- They need a large amount of current “surge” when the compressor starts.
- Energy is lost when the current is converted to AC and back to DC.
- They require substantial battery power to run when there is no sun.
DC Solar Air Conditioners
DC units eliminate the wasteful conversion from AC to DC.
The problem with running the air conditioner directly from the solar panels is that the current fluctuates during the day, particularly when there is cloud cover.
DC air conditioners overcome this by using MPPT (Maximum Power Point Tracking), stabilizing the current.
The advantages of a DC unit are as follows:
- A DC air conditioner leaves the two AC/DC conversion steps out and uses the native DC directly from the solar panels.
- Most DC inverters use a “soft start” technology that minimizes the “surge” current needed to activate the compressor.
- DC units do not need an inverter between the solar panels and the system.
The disadvantages of a DC unit are listed below.
- DC air conditioners need large-capacity battery storage
- They generally cost more than AC-powered air conditioners
Hybrid Solar Air Conditioner
As the name implies, hybrid solar air conditioners can operate on DC or AC. This means that during the day, when there is plenty of sunlight, they can draw current from the solar generator. At night or when there is cloud cover, they can switch to AC and draw power from the utility.
Solar Generator Compatibility With Air Conditioners
Generally, a fully installed solar system is the optimal solution to run air conditioners. High-powered air conditioners use large amounts of electricity, which means solar systems with many solar panels and excess capacity from solar batteries are needed.
Despite this, it is possible to run air conditioners from a solar generator; however, the power requirements must be carefully considered.
Choosing the correct solar generator is essential. The typical power requirements of AC-powered solar air conditioners are listed below.
|BTU Size||Current Type||Running Watts Required (kWh)||Initial Surge Watts Required||Number of hours 1 X 3kWh battery will run|
|5,000||AC||200W-500 kWh||1,000-1,500W||6 hours|
|7,000||AC||400W-700 kWh||1,400W-2,000W||4 hours|
|10,000||AC||500W-800 kWh||1,700W-2,200W||3 ¾ hours|
|13,500||AC||700W-1,500 kWh||2,500W-3,000W||2 hours|
|15,000||AC||800W-2,000 kWh||2,800W-3,500W||50 minutes|
|24,000||AC||1,200W-2,800 kWh||3,800W-4100W||45 minutes|
|10.000||DC||300 kWh||1,000W||10 hours|
The size of the generator will be determined by the running watts and initial surge watts consumed by the air-con.
For example, an air-conditioner rated at 10,000 BTU will require a solar generator with the following capacities:
- Normal running power – 0.8kW
- Surge Power – 2.2kw
- Night time running – 10 kWh batteries (8 hours)
The factors that will impact these values are as follows:
- The air conditioner’s compressor generally runs 2-3 times every hour for 15-20 minutes.
- Increasing the temperature setting reduces the running times and the power consumed.
- The higher the ambient temperature, the more often the system will need to provide cooling air.
Setting Up And Running The System
The factors to consider when setting up a solar generator to run an air conditioner are listed below.
Before installing the system, first, answer the following questions:
- Do you intend to run the system overnight? If the answer is yes, it is important to calculate the battery capacity you need to do this.
- Calculate the number of solar panels (and the capacity) required to keep the battery charged and to run the system during the day.
- Ensure the inverter is sized correctly and meets the air conditioner’s power requirement (for both running and surge power).
Installing a solar generator is very simple and only involves following the instructions issued with it.
Running The AC Unit
Always ensure the solar generator batteries are sufficiently charged before connecting and switching the air conditioning unit on.
Depending on the battery type, it can only be discharged (depth of discharge) to a certain level beyond which battery damage will occur.
Although not ideal, running air conditioners off a solar-powered generator is possible.
1️⃣ The main consideration is the battery capacity included (or that it can be attached to) with the solar generators.
2️⃣ Another consideration is the amount of surge power the air conditioner draws each time the compressor starts (2 -3 times per hour.)
3️⃣ DC air conditioners are more expensive but draw less power and are therefore more suitable to being powered by solar generators.