Micro Air easy start

[ronthet]

I have seen youtube videos on this, but wandering if any Forest River Rvers have had this installed on their rv say with the dometic 15000 btu unit. I see that 2000 watt generator are suppose to be able to run the Ac with this installed. Anyone out there had it done. Or can anyone suggest size Inverter/generator need to run the 15000 btu unit.

[SeaDog]

The problem is not with running its with starting the AC compressor. The typical AC runs on about 10 amps or 1200 watts but can require up to three times that amount to start. So a generating system that can handle a momentary 3600 watt surge be in the range. I run 2 yamaha's 2000s in parallel and have no problems. I do have a hard start kit on my AC

[Brewhedd]

I installed one on my 15k unit. Now able to run ac with generac 2k generators. Haven't tried one. As mentioned the starting current can be over 30 amps, probably closer to 40 for a 15k. A hard start capacitor does not reduce the start current.

[SailorSam20500]

A search with term microair will pull up a number of threads where people discuss these. One member recently sold a couple that he removed from a trailer he sold. He plans to install new units on his new trailer after the AC warranty expires.

[SailorSam20500]

Additionally, On the Airstream forum has a long thread where the Easy Starts get discussed. Go over there and read thru this one and some others on that site: Can Generators Run Both AC's While Boondocking.

[dcling]

Originally Posted by Brewhedd

I installed one on my 15k unit. Now able to run ac with generac 2k generators. Haven't tried one. As mentioned the starting current can be over 30 amps, probably closer to 40 for a 15k. A hard start capacitor does not reduce the start current.

I am able to run my 15k a/c unit on one generac 2k generator in normal mode.

[Brewhedd]

Originally Posted by dcling

I am able to run my 15k a/c unit on one generac 2k generator in normal mode.

I'll have to try that. I assume you have an IQ 2000. I am not impressed with them at all. When running both they start the ac fine. When they slow down after the ac startup surge to the running current they slow too much. This causes the ac blower to slow momentarily. Don't get why this happens.

[garbonz]

Micro airs are the next best thing to sliced bread. It greatly reduces the stress on the small generators whether they can start the AC or not. Really, they are awesome.

[jeffnick]

My Micro air worked well on my 13.5 ac with my Honda 2000i until I got into 90+ temps at higher altitudes.

[SailorSam20500]

Originally Posted by jeffnick

My Micro air worked well on my 13.5 ac with my Honda 2000i until I got into 90+ temps at higher altitudes.

Not particularly surprising. High altitude decreases the engines power, reducing power output.

Did you put high altitude jets on the generator to compensate?

[jeffnick]

Originally Posted by SailorSam20500

Not particularly surprising. High altitude decreases the engines power, reducing power output.

Did you put high altitude jets on the generator to compensate?

When doing cross country, this might mean changing jets every few days?

[pgandw]

What happens when you go up in altitude with a non-blown engine? The air pressure which pushes the air into the engine is significantly reduced (oxygen percentage in air does not change). The maximum air pressure inside the engine is about 20% lower at 6,000ft, and power generally drops about 25%. Inside the carburetor, the venturi effect is non-linear to begin with, so the fuel air ratio from the carb will change with altitude, resulting in the engine being richer at altitude. High altitude jets correct the fuel air ratio but do not increase the power out (except for the very slight increase from leaning the mixture).

The primary benefits of re-jetting and/or carb adjustments are easier starting and smoother idle. At higher RPMs, the rich mixture tends to foul your plugs and uses more gas than at optimum mixture. If you do re-jet, and forget to change the jets back when you come down, you are now running lean, and can damage the engine from being too lean and too hot.

In an ideal world, you advance ignition timing with altitude, too. The flame front does not travel as fast in the thinner air. Again, coming down you have to retard the timing back to its "normal" setting.

Electronic fuel injection optimizes the mixture for ambient pressure, but can't recover the power from the air pressure loss. The same with variable timing. The real cure is turbo- or super-charging to maintain the pressure into the engine.

Unless you are going up to 9K or 10K, re-jetting is seldom done unless you really want to optimize, and are staying at a given altitude for a while. If you are up at 9K+, you don't need air conditioning, so the generator running like crap (or not starting) isn't as much of an issue.

things I learned from flying carbureted aircraft and living at 7800ft
Fred W
2014 Rockwood A122 A-frame
2008 Hyundai Entourage minivan
camping Colorado and adjacent states one weekend at a time

[SailorSam20500]

Thanks pgandw, I read forums to learn. Your post has upped my knowledge level. I've never understood what really happens as altitude increases in a NA engine. Just that many folks have said they rejet for high altitude. Now I think I know why and when it should be done along with the actual benefit of doing the work.

[My17Ram]

Originally Posted by SeaDog

The problem is not with running its with starting the AC compressor. The typical AC runs on about 10 amps or 1200 watts but can require up to three times that amount to start. So a generating system that can handle a momentary 3600 watt surge be in the range. I run 2 yamaha's 2000s in parallel and have no problems. I do have a hard start kit on my AC

I just installed one on my Coleman Mach 13500 unit and am successfully running the AC with my new Predator 2000 inverter.

There are two conditions to overcome: startup (inrush) current and running current. The Easy Start addresses the inrush current by reducing it in my unit from about 40 amps down to 17 amps, allowing a very small generator to start the compressor.

Running current is most assuredly way above 10 amps as stated above, especially for a 15,000 btu unit. My 13,500 btu unit runs at 13.5 amps on an 80 degree day and would be slightly higher on a hot day. My Predator is able to sustain this load, but requires all other 120v loads to be shut off (converter, etc.). Bottom line, make sure the generator you choose is capable of producing sustained wattage sufficient to run the AC, and realize the Micro Air Easy Start only addresses the startup inrush current, which it does very well.