Off grid power solutions

Close Comfort PC9+plus runs on AC 240 Volt 50 Herz power supply, which is the standard Australian residential power supply. Close Comfort has the lowest power consumption of any air conditioner on the market in Australia which makes it particularly suitable for off-grid applications.

If you are unfamiliar with off-grid power solutions, there is a technical note with some explanations so you can understand the technology.

If you plan to operate your personal air conditioner away from normal AC power supplies, for example, on batteries, solar panels, or a generator, this page provides suggestions.

Please note that our product warranty covers normal use on specified power supplies. It is your responsibility to ensure that your power supply conforms with the product specification requirements with a minimum supply voltage of 215 Volts AC.  Running the AC on a lower voltage can damage the compressor and other motors.

We recommend that you thoroughly test any alternative power supply before departure from your home base.

 

For Battery and Solar system

A typical off-grid power system consists of a series of solar panels, an electronic inverter to convert DC solar power to AC power for household appliances, and a storage battery to provide power when there is insufficient solar power.

Choosing the Right Inverter

In common with refrigerators, Close Comfort draws a very short burst of high current to start the compressor, around 5 - 7 Amps.  The normal operating current is about 1.3 Amps.  

You should choose an inverter with a peak (starting) load rating of at least 1800W (2100W is recommended), and a steady load rating of at least 350W.  The peak load will only last for 5 - 15 milliseconds at the time of starting the compressor each time.

You should account for the load of all your other appliances that could possibly be in use at the same time, then add that to the constant load.

We recommend that you test Close Comfort unit on your preferred inverter product first before purchasing. Make sure the unit is in Cooling mode.  The ambient temperature must be at least 20 °C. Run the AC on the inverter for at least 10 minutes, switch off the AC, then switch it on again, and test for a further 5 minutes. 

PC9+plus can operate on both a pure sine wave inverter and a modified since wave inverter. While the former is usually much more expensive but has a higher efficiency (85%- 95%), the latter one is more common and affordable, except it has a lower efficiency (60%-85%). 

Battery Type

There are many different types of rechargeable battery that you can use with an inverter. 

Standard lead-acid car batteries will work, but you can only draw about 40% of the battery capacity.  Therefore it is better to purchase "deep cycle" lead-acid batteries.

Today, the best battery option in terms of weight, durability and life cycle cost is a Lithium Ion battery.

Make sure the battery voltage matches the inverter input voltage.

Determine Battery Size

We assume the following:

Using 12V system.

PC9+plus operation hours: 7 hours

Inverter efficiency: 85% (Good quality modified sine wave inverter)

Depth of discharge: 95% (deep-cycle battery)

Constant power demand = 300W.

With a 12V battery, the current will be 300 / 12V = 25 Amp (Make sure the wire you use will can carry 25A constant current).

Peak power demand is about 1800W for 10-20 milliseconds.

1800 / 12V = 150 Amp  ( Make sure your battery has a CCA rating equal or higher than 150 Amp)

The battery size can be roughly estimated with the following equation:

(duration x steady battery current) / (depth of discharge * inverter efficiency)

Based on the above figures, the equation gives:

(7 hours x 25 Amp ) / ( 0.95 depth discharge x 0.85 inverter efficiency ) = 216.7 Amp-hours

Round it up to 220Ah. This is the smallest battery size it requires to run the AC for 7 hours. Please note that using Close Comfort with the Igloo tent can extend the operation time by about 30 to 40 percent.

Please also allow extra capacity for other appliances that could possibly consuming power at the same time.

Solar Panel

If you plan to use Close Comfort in a solar powered house (usually 3.2Kw or more), then just plug it in and use it just like any other appliance.

For car or caravan solar panel, the user will need a suitable solar inverter in order to use Close Comfort.

The solar inverter should be able to charge your battery as well as run the appliance.

 

Generator System

Close Comfort air conditioners can run from small 240 Volt AC generators.

Choosing a generator is very similar to choosing an inverter as stated above.

The generator should have a rated peak load of 1.8KW or higher, and a constant load of 350W or higher.

Most generators can run more than one Close Comfort unit at the same time.