Micro-Air’s EasyStart reduces the power requirement to start and run rooftop air conditioners
A frustration that trailerists have been grappling with for decades is the difficulty of running an air conditioner on a compact, easy-to-handle portable generator when boondocking. While it’s possible to lug around a larger and heavier generator that’s more difficult to maneuver, many RVers prefer to use a 2,000-watt model for its convenience and versatility. Most rooftop air conditioners can run on a high-quality 2,000-watt generator once the compressor starts, but that’s the rub. The popular 2,000-watt generators do not have the capacity to start a 13,500-Btu air conditioner. Two of these generators must be tethered together in parallel with a connection kit to produce enough amperage to start the air conditioner.
To fix this, Micro-Air created an electronic soft-start system for RV air conditioners called EasyStart, which reduces the amp-draw spike normally necessary to start the compressor. The system replaces the air conditioner’s original start capacitor and provides a four-stage ramp-up start for the compressor, timed with the starting of the fan, which, according to the company’s data, reduces starting amps from 65 to 75 percent of the compressor’s locked rotor amps (LRA) rating.
A few RV manufacturers started installing this technology into their rooftop air conditioners in 2017, and in 2018 Micro-Air introduced EasyStart units to the RV aftermarket, after a run in the marine industry where the company still participates.
The obvious benefit of the EasyStart is the ability to start and run an air conditioner on lower current, and even run two 13,500-Btu units on 30-amp service, with proper energy management. That means it may be necessary to shed other loads, including the battery charger, to run the two air conditioners simultaneously. The same concept applies to running three 15,000-Btu air conditioners on 50-amp service.
Current inverter and lithium-battery technology makes it possible to run one EasyStart-equipped air conditioner for a while on a suitable inverter. This, of course, is predicated on the size and heft of the battery bank and recharging provisions, but that’s another story.
The not-so-obvious benefits are reduced noise when the air conditioner starts, and the ramp-up is actually kinder on the compressor than the jolt it gets when the compressor engine “slams on” using the stock capacitor. Additionally, when operating an RV on a generator, there’s usually a limit to the number of accessories that can run simultaneously. For example, if the air conditioner was running when the converter/charger kicked in, the generator would likely stall, especially if the air conditioner shut down and restarted with concurrent loads. The EasyStart makes it easier to calculate and manage loads, running more appliances and accessories while operating the air conditioner.
Setting Up the EasyStart
Installation is pretty simple, but if you’re queasy about working with high voltage and wiring, leave the job to a professional. The EasyStart works on all RV air conditioners,
regardless of the thermostat and circuit-board type, because it connects only to the compressor and power. The unit consists of a tan box containing a circuit board with proprietary software and a wiring harness. The software actually studies the particular compressor, “learns” its unique characteristics and programs it to minimize the power requirement.
The optional installation kit contains all the parts needed for the installation, including cable ties and solderless connectors, along with detailed instructions. The Micro-Air website has videos and additional documents that provide step-by-step procedures, wiring instructions and other information that is useful when installing the system.
Tech Tip>> Before tackling this project, make sure the roof
is clean and dry, all sources of 120-volt AC power are disconnected, and the start capacitor is properly discharged.
Before tackling this project, three safety warnings must be heeded. First, obviously, you’ll be spending time on the roof of the RV, so it should be clean and dry. If you’re uncomfortable with heights, don’t even consider doing this installation yourself. Second, make sure all sources of AC power to the RV, including automatic-starting invertors, are disconnected. If the RV has a generator with a self-start feature, make sure the generator breakers are off.
Lastly, the start capacitor that you may be working with can contain high voltage and give you a good jolt, so be sure to confirm that it is discharged using a multimeter set to DC volts. The correct way to discharge a capacitor is by using a 1,000-ohm resistor across the terminals or using a light bulb and socket. Most of the time, shutting off the power to the air conditioner with the unit running will be enough to discharge the capacitor.
Instructional photos are provided here for installing a Coleman-Mach unit and are generalized for space considerations. The process differs slightly depending on which air-conditioner model is being modified, so follow the instructions that come with the EasyStart.
After the EasyStart is installed and shorepower is restored to the RV, the start sequence can be initiated. This is done by cycling the air-conditioner compressor five times. The simplest way to perform the programing is to set the thermostat and allow the unit to go to work. The EasyStart uses these start sequences to “learn” the compressor. This will take some time to complete, but once it’s done, the unit can be started on a generator or inverter. EasyStart’s design includes a five-minute delay between starts to protect the compressor’s motor. Alternately, start sequences can be accomplished using two 2,000-watt or larger generators running in parallel with Eco mode off, if hookup power is not available.
An EasyStart unit will be needed for each air conditioner.
Measuring Peak Output
The only way to accurately record the start-up surge is with a sensitive recording ammeter. When the Micro-Air staff demonstrated the system, we saw a significant decrease in the starting amperage (see the “EasyStart vs. Conventional Start” graph). The 15,000-Btu Coleman-Mach unit’s compressor will have a start load of up to about 59 amps with just the stock capacitor, which is reduced to 20 to 23 amps with an EasyStart installed. The 13,500-Btu Coleman-Mach unit will require up to 50 amps to start unmodified, and this requirement is reduced to 16 to 19 amps with the EasyStart installed.
Micro-Air demonstrated that the Honda EU2000 portable generator, for example, will run a 15,000-Btu air conditioner; however, this is dependent on other loads being opened and the elevation at which the generator is being operated. According to the engineering staff, the EU2000 has been able to achieve a peak output of 3,300 watts over a short period of time in laboratory testing, but some lesser-quality portable generators were not equally capable.
EasyStart electronic soft-starter units and instructions are available from select RV service centers and directly from Micro-Air for most current-production RV rooftop air conditioners, including Advent, Coleman and Dometic, as well as legacy brands like Armstrong and Carrier.
The EasyStart 364, which we installed, has an MSRP of $299, and the optional installation kit runs $9.89. The unit comes with a two-year warranty. For an additional charge, Micro-Air offers an extended warranty, called the Double Down Warranty, that covers compressor failure.
Chris Dougherty is technical editor of Trailer Life and MotorHome. Chris is an RVDA/RVIA certified technician and a lifelong RVer, including 10 years living full time in an RV. He and his wife make their home in Massachusetts and hit the road in their heavy-duty truck towing their travel trailer every chance they get.
An RV/MH Hall of Fame inductee and publisher emeritus of Trailer Life and MotorHome, Bob Livingston has written countless RV technical and lifestyle articles and books, and created and appeared on the weekly television show RVtoday. A lifelong RV enthusiast, Bob now travels and lives full time with his wife, Lynne, in their fifth-wheel trailer. He continues to be a regular contributor to Trailer Life.