EasyStart™ Installation FAQs
Success with EasyStart™ on Inverter Generators
Many customers ask us if their inverter generator will operate their air conditioning unit. Sometimes this question is because they read on the internet that a 2000 watt inverter will run their rooftop AC unit. Other times they purchased a generator or inverter and found that it won’t reliably start their air conditioner so they search for a solution. EasyStart™ is a great solution for many of these situations but there is certainly more to it than that.
What does EasyStart™ do and how does it work?
Consider how a regular compressor starts. When power is first applied to the motor it creates a magnetic field that presses against a rotor. The rotor is connected to the compressor and these components have mass so it takes time and energy to get up to speed.
Compressor motors are connected in a way that lets them draw as much energy as needed to get up to speed quickly. Because of this design the motors draw a huge current surge when they start.
On every motor plate there is a specification called LRA. This stands for Locked Rotor Amps and is the maximum current the motor can draw according to the manufacturer. During a start you can expect your compressor to draw this current from the supply.
RV rooftop 16 KBTU compressors are rated around 50 to 60 amps LRA. A typical 2000 watt inverter generator is rated at 2000 watts peak which is about 16.7 amps at 120 volts AC. There is no way will the generator start a load that draws four to five times its peak rating!
The solution is to reduce the peak LRA so we created EasyStart™. EasyStart™ is designed to connect directly to the compressor motor and reduce the power surge that occurs on start. It does this by controlling the power supplied to the windings of the motor on each AC cycle. EasyStart™ gradually increases this power until the compressor is running.
This increases the time it takes the motor to get up to speed and creates a very smooth start that reduces the peak current by 50 to 70%. An RV rooftop 16 KBTU, 120 volt compressor can now start with under 20 amps of current.
What do I need to know to use my Rooftop AC with an inverter generator?
The idea of these small light weight generators is so appealing that they have surged in popularity over the last several years. Many companies are making them and they are not all equal in ability. These generators are rated for both continuous output and peak output but some are very under rated.
The Honda eu2000i and Yamaha EF2000iSv2 are the most popular and arguably the industry standard. These two generators can easily produce more than their rated power to start and run a rooftop AC unit with EasyStart™.
Yamaha’s earlier EF2000iS generator was not as robust though and would overload if pressed to run a 15 to 16 amp air conditioner. We recommend researching reviews, blogs, and RV websites before selecting a generator.
There are still more considerations to take into account. How you will use the generator is just as important. The above mentioned generators are working above their 13.3 amp rating to run an air conditioner. Don’t expect to add any other loads to a single generator while the air conditioner is running.
This means you may need to turn off any powered appliances including the battery charger and refrigerator. Easy solution is to buy a bigger generator but that means more cost and weight. Most people just make do with the limitations, it is camping after all!
Since air gets thinner the higher in elevation you go, altitude also affects the generator, and it will likely not have enough power at or above 4000' to keep your A/C running, even though EasyStart may have been able to start it. Above 4000', you may need to re-jet the carburetor to get the generator motor to produce enough power. Depending on all the altitude and air temperature (i.e. "density altitude"), re-jetting the carburetor may or may not adequately extend your altitude range.
Be aware that running at lower altitudes again will require the jet change again or you risk high combustion temperatures and burned engine components. Honda makes high altitude kits for its generator and some Yamaha dealers can also provide jets for those generators.
Will I still need EasyStart™ if I have a bigger generator or parallel two generators?
That depends on how big a generator and what you want to run at the same time. Without EasyStart™ the start surge is huge. Generators respond to this load by slowing down and reducing the voltage to the air conditioner. If they slow down enough they go into overload and the air conditioner won’t start.
Air temperature also affects the air conditioner. Higher outside temperatures raise the refrigerant pressures causing a higher current draw. We have had some customers with Honda EU3000iS generators tell us that the generator will not start the air conditioner reliably when temperatures get hot. Most 4KW generators will start a single rooftop air conditioner reliably but that’s a lot of size and weight.
Are there any other benefits to running EasyStart™?
EasyStart™ is the only starting solution that will allow reliable starts from energy saving generator modes. Many small generators have a switch that throttles down the motor saving a lot of wear, gas and extending the operating time.
Generators are also considerably quieter in this mode. EasyStart™ allows you to save fuel and reduce noise whenever the compressor is not running.
With this as an overview, we offer the following list of more in-depth FAQ's specific to brands and models you may be using.