Foretravel Owners' Forum

I plan to add a Micro-air Easy Start to the front A/C this weekend, which should put it within the specs of our new inverter (Verrrry close to putting some units within the specs of the popular Honda 2000W generator, for those who may be interested in that route).  There is a great video linked on the Easy Start website that is full of very interesting tests, and includes an example installation - but it is 34 minutes long and not a great quick reference if you are looking for a refresher on what is about a 4 minute re-wiring install on the video. http://www.youtube.com/watch?v=soP0uZFd0nQ&feature=youtu.be

So I grabbed a photo of the wiring diagram used in the example video, and made an "illustration" of the install they did on the unit in the video.

I then took our Duo-Therm's wiring diagram, and marked it up the same way with the wiring changes I need to make for the Easy Start install.  I emailed the diagram to Micro-air for confirmation, and within a few hours they had it forwarded to an engineer who responded to me that the wiring diagram was correct. Good customer service!!

I've attached both diagrams below - maybe this will save some time for someone doing something similar at some point.

Note 1: In case of interest, Easy Start can be purchased here: Micro-Air - Products (http://www.microair.net/main/products/product.php?id=20) and you can get $50 off by entering the code "GWTW" at checkout.  No affiliation - just trying to save an interested party the $50.
Note 2: I do realize that i should have marked up the 'left version' instead of the 'right version' of the original wiring diagram, but I used the right for illustrative ease.
Note 3: If this doesn't work, I'll come back and update appropriately.

Easy start will reduce the LRA of the AC start. What are the predicting it will be reduced to? They are a reputable firm, and seem to focus on the 115v rv market.
SureStart makes a similar product, and almost all 115v rv and Marine AC will start and run (a single AC unit) on a Honda 2000i inventor, so I suspect the Easy Start will as well.
Running AC on battery, it will be interesting to see how that goes. What is FLA of your running AC? Might be nice to run one roof air off inverter while driving (vs run generator). But usually I seem to end up with Two AC running in my 40' coach when I need AC to cool coach while driving. I am more likely to be happy with just one running now that I had FT extend the vents forward from factory stock location Two soft starters, one on each AC might allow both units to run on a 30 amp service, if other loads kept to a minimum.

If you have problems, just give MicroAir a call, an engineer will help you out. I called them to ask how the black-box works and they are great to do with. They really do work...I spoke with the owner of a marine A/C company that is a mechanical engineer and he said "I don't know what magic goes on inside that box, but it allows our customers to run our units on small generators when they couldn't before".

For the trivia: MicroAir makes many/most of the controls for Dometic CruiseAir marine a/c systems. Dometic does make their OWN soft start (which is odd, because they usually outsource such things), but it isn't as good.

This soft start isn't a traditional VFD type soft start. What it does, if I remember correctly, is use PWM to slowly ramp the voltage up on the start and main windings (which doesn't cause such a current surge).

Actually, Dometic OEMs the Hyper SureStart and calls it SmartStart. It is not made in house.
Dometic has the in house expertise to test various soft start options. They chose to OEM the SureStart over the cruise air product due to its superior LRA reduction, durability, and UL listing.
Easystart would of course claim superiority to the Dometic product. They want you to buy their product.  Ask yourself, If the EasyStart is superior and cruise air already sells OEM control boards to Dometic, surely Dometic would buy the EasyStart instead of the SureStart (OEM'd as SmartStart.) if it was superior.
That being said, EasyStart tech assistance is superior to Dometic, especially for a DIY install. RV A/C wiring varies from brand to brand and model to model. Having someone to call and check wiring and confirm install is a considerable benefit.

I have no idea which is "superior". I've seen some internet tests that show the microair product "wins", but who knows.

As for why Dometic would use something else instead of from Microair product??? Well, big corporations often make decisions that don't seem logical, cost more, and provide a crappier product (I've seen it many times). So I would never assume they chose the best....but the SmartStart may be the best! I'm just debating your conclusions that Dometic OEM'd the smartstart thus it automatically is more bester.

No worries Krush.

While I don't pretend to understand how a soft start works, the Easy Start is advertised as a "different type" of soft start.  In this case, the research cost that goes into a new technology could be a significant barrier in immediately applying it into commercial applications and contracts.  Cost is a plausible reason to use an existing technology that may be inferior, particularly because that technology is perfectly sufficient for most applications and we all get on fine with it as-is.  Just spitballing / conjecturing.

TIm. the LRA is either 50 or 60 on my unit (Did not pull cover to check exact model because it was inconsequential to my conclusion).  That equates to a 5750-6500 Watt surge, and exceeds both the 100 msec 40 AMP surge rating (and less consequentially, the 5 sec 3900 Watt surge rating) of the magnum MS2812 inverter.  Easy Start advertises itself as an 'at least 50%, up to 80% reduction' in compressor LRA.  In the example Easy Start video, LRA is reduced from the mid-40's to 17.3.  But I'd be fine with a 50% reduction.  An LRA of 25-30 amps puts everything within the recommended specs of the inverter, provided I don't have any other power hogs running.

After the compressor kicks, continuous power tops at 15 AC amps -> 1725 Watts, well within the 2800 W continuous rating of the inverter - so no problems there.  Although, I guess that is easy to say when it's all still numbers on paper!  We'll see how it works in practice.

James

James,

SureStart guarantees 60% LRA reduction off the sticker LRA or your money back.
So a rated 60 LRA would be 24 LRA worse case after Application of SureStart.  Easy Start likely similar.  The start sequence is about 300 milliseconds, so a 40 amp surge rated inverter should easily start the AC if the Sticker LRA is 60 Amps and the EasyStart reduces LRA in a similar amount to the SureStart.
Interested in your view on the relative superiority of the EasyStart, in what way is the device more effective or "better" than the SureStart/SecureStart (Emerson OEM name)/SmartStart(Demotic OEM name)? (Both Emerson and Dometic OEM SureStart, you can find information on each of their websites.) Easy Start and Sure Star both "learn" during the start sequence, and modify the start parameters to optimize the start of the compressor going after 10 starts.  Most commonly with SureStart you will see starting LRA of about 35% of rated LRA after 10 starts. Sure Start continues to monitor start performance and adjusts the start parameters as the compressor behavior changes over time with age or environmental stress.
Actually, the devices are quite similar, both having an on board Start capacitor and logic board to monitor run information on the run winding. Primary difference between SureStart and EasyStart is that SureStart is UL approved, no doubt a safety and liability concern of Dometic and Emerson and a factor in the decision to OEM SureStart.  Not sure why EasyStart has not pursued UL approval of the device.
Do you have an oscilloscope of high end fluke meter that could capture inrush information before and after you install the EasyStart?  In that way you can see the improvement and then know exactly the load on your inverter at startup.
Good luck and keep us updated!

That sort of a technical opinion is one that goes well beyond my comprehension level - and any opinion I put out there would simply be a regurgitation of advertised bullet points, so not very useful.  My personal purchasing decision was made upon a viewing what I felt was an authentic video example that decreased the LRA of a slightly smaller A/C unit by more than half.  And while I don't own any sort of measurement device to indicate what the effect will be on my particular unit, the engineer did use two different units simultaneously in the example video, so the best I could do to semi-respond to that question is to direct you there:  http://www.youtube.com/watch?v=soP0uZFd0nQ&feature=youtu.be

There is a direct comparison from the Easy Start to the Smart Start here: http://www.microair.net/main/products/specsheets/EasyStart_Spec_Sheet.pdf
It is on the Easy Start product page, so take the claims with a grain of salt - I'm sure there are some 'missing' bullet points on the side of smart start - but I'm not sure any truly unbiased comparison exists between the product types we are talking about.  Perhaps I have just been falsely persuaded that one similar product is better than another!

But in reality, as long as it works, then I'll be happy - I plan to play the inverter load as conservatively as possible - and so exact performance isn't as important to me as meeting those attainable benchmarks.  Because I felt like I saw authentic evidence that the Easy Start met that benchmark - I went with that unit.

Just re-read this.  I meant to specify that it might start without switching off EcoMode on that generator.

On the youtube video you linked, there is a good comment (I pasted part of it below). For me, let's assume both products are adequate. Well, MincroAir spent 10 minutes on the phone with me...and it was an engineer that knows the stuff. They also made a great video to show the system at work and how to install it. It's a small business made in USA owned by Americans. We can all choose were to spend our money......

As for UL approval. Both are CE, which is sufficient for me.

Krush, agree that they are very good on the phone support of the product, especially with regards to RV air - let us know how it works out - was not trying to start a debate!

Tim

For anyone who hasn't pulled the trigger on a new inverter yet, there are high surge inverters available now - no extra soft start box required. I installed this Aims 4000 watt (https://www.amazon.com/Power-PICOGLF40W12V120V-4000W-Inverter-Charger/dp/B00JBND8VK/ref=sr_1_1?ie=UTF8&qid=1487873420&sr=8-1&keywords=aims+4000) with 12,000 watt surge and along with the 300 amp Delco alternator upgrade I was able to start and run the front roof air in our ex-U300.

How was that thing on noise production?  Reasonable to sleep next to with no A/C / furnace / generator running to drown it out?  Any comparisons?

The Aims has a muffin fan that runs all the time. I mounted in the center basement bay. No issues with noise up in the coach.

Wired the Easy Start in today.  Took about 90 minutes.  Would have taken about 45 minutes total - but had to run to the hardware store because my closed-end crimp connectors were too small.  After doing the pre-identification work on the Duo-therm's wiring diagram, it was very easy to identify which wires were needed, despite the "wiring mess" inside

Have no idea the A/C will still work, though!  We've been boondocking for the last 10 days or so - need to check into a campground so we can get this thing to "learn" the A/C on utility power.  Then we'll rewire the A/C through the inverter breaker box, and we'll really get to see if this was a success.  I'll check back and update whenever we get around to that.

Yes, please do, there are several forum members on the edge of their chair waiting for this result  ^.^d

Well it hit 95 degrees three separate days this week in Appalachian Virginia where we are currently posted up, so it's time to update this thread!

We aren't in campgrounds much, so while we were dumping and filling at a campground on the way home from Nacogdoches last month, I also plugged in to the 50amp, and started up the A/C 7 times to finally complete the "easy start learning process."  At first, I was pretty discouraged because the A/C wouldn't start up, and I thought I messed up the wiring.  But I solved that problem in the best way possible, by flipping on the breaker that I had never turned back on after wiring in the East Start.  Phew!  Everything ran normally.

Today, I finally got around swapping the wires over from the main breaker box to the inverter breaker box.  And we ran the A/C for five minutes on battery power to test!!  Here are the results:

Running Amps:
117 amps on low.  130 amps on high.  On high, this is about 1500 Watts, well within the 2800 Watt continuous power rating of our Magnum MS2802.  In terms of continuous power usage, think of it as the same thing as running your microwave on the inverter.  We have a big ol' 1200 AH AGM battery bank, and 1140 Watts of solar.  We're usually fully charged by 11am or so, which means on a sunny day we can get away with running the A/C for 45 minutes or so around mid day, and still finish the daylight hours fully charged.  We pull in 60 amps in favorable sun, which means the draw on the bank will only be 60-70 if the sun is out.  (If that doesn't prove to be true, I will report back)

Compressor Surge Power:
Air Compressor Surge:  When the Air Compressor kicked in the very first time on the inverter, the magnum display jumped to 400Amps.  Factoring in the 65-70% efficiency for this intense draw, that works out to be 4800 Watts Dc Input to  3500 AC Watts output.  BUT - the next three times, we started it up, there was no jump at all.  Barely went above the standard running amps - and didn't see a reading above 150 amps.  I'm not sure whether the discrepancy was a "learning" issue for the easy start computer, or the inability of the magnum to display power surges quickly enough before they dissipate...  I'm going to assume the former, but will report back if I start seeing high power surges on the magnum moving forward.

However, regardless - these readings are within the specs of the inverter:  8400 Watt 1 msec surge, 4800 Watt 100msec surge, 3900 Watt 5 seec surge.  I feel comfortable that starting the A/C [post-Easy-Start-install] will not do irreparable damage to the Magnum inverter in the short term.

If I'm wrong, I will be sure to report back so you don't spend $$ on the same mistake.  But in the meantime, I'll enjoy our "free" air conditioning!!

Excellent report! I have long planned on doing the same with our 3000W Magnum Hybrid inverter and a Sure Start Soft Start from Hyper Engineering Sure Start Soft Start (http://www.gen-pro.biz/single-phase), but re-roofing this 400 foot trailer of our home base is taking up almost all my time as we get ready to depart for Canada in late June. I have to make sure that this house-of-cards built Woodland Park trailer protects our goodies while we are gone. Our AGM battery bank consists of 4 8D's for a nominal total of 980AH, and when finished the solar will total 904 watts, and eventually a brushless Delco 40SI alternator (Amps depending on the best bang for the buck, but likely 240 amps). My goal would mainly be to be able to use the house A/C to supplement the dash A/C while driving, but I can imagine running one A/C for 30 minutes or so while parked when returning to a hot coach mid day. I will be tracking your impressions as you live with it for awhile... ^.^d
Don

Thank you for the update. Sounds like you confirm Mirco-Air easystart does as advertised!

Where do you find the "favorable" sun to give 60A out of 1140w panel array?

We get 50-60A on a daily basis pretty much anywhere with no clouds in the sky.  Closer to 50A during the late winter months in Maryland.  Closer to 60 during our trip to Missouri/Kansas/Texas.  See 55-58A in full sun in Covington, VA where we currently are.

Credit to John Palmer (Palmer Energy Systems - Mayo, FL).  I suggest searching the forum for John Palmer!

We've used the A/C on battery power 7 or 8 times, so time to report back on some items of note:
Refresher on our setup summary: 1170 AH batteries (585 AH usable), 1140W solar on roof, Magnum MS2812 Inverter, Micro Air Easy Start wired into original Duo Therm A/C.  Re-wired front A/C unit through the inverter breaker box to use A/C on battery power.

1) We're generally running the A/C for 45-60 minutes.

2) Display suggests this draws (net) in the 100-140 Amp range, depending on state of the sun.  It ends up using 100-150 AHs of battery power total.

3) The primary item of note is that the use of the A/C is not sufficient to kick the solar charge controller out of float charge mode and back into bulk charge mode.  As per the TriStar MPPT manual, the charging schedule for a given day is determined by the overnight low voltage from the previous night.  So apparently, once the TriStar sees 95%-100%, it pops into float charge mode, and remains there until the next day.  Perhaps one would be able to "reset" this, and restart the bulk charging by temporarily pulling the charge controller fuse for a few minutes - but then does one lose the controller's "learned" size of your battery?  Not sure, but I haven't tried this yet. For comparison's sake, I popped the generator and turned on the MS2812 charge feature, but it also functioned the same way.  Stayed in float charge mode, even after pulling the batteries down to 12.6V or so.  I found this strange.

4) I've seen higher compressor kick spikes than I was hoping - the magnum display suggests a split second kick to about 450 Amps.  So, a 5000+W spike. When factoring in the high draw inefficiency power loss this value includes (I believe), it is still within the surge specs of the MS2812, but not by a whole lot.  However, for the sake of scientific research, we've decided to continue using the A/C through the inverter.  If something goes wrong, we'll report back!

5) Using one A/C for an hour is not useful for dealing with mid-day 95 degree temps - that still requires a two units and a generator - but an hour of one A/C unit is very useful to speed up cooling down an 85 degree interior to a more comfortable 78 degree interior before bed when the exterior temps and the Kool-Matic wouldn't allow for an efficient process.  As such, we find ourselves using the A/C on battery power more as the sun is going down.  Didn't expect to be using it this way, but the float charge behavior in #3) above made this the most viable option.

6) With a conscious energy day and some sun, we generally hit the "full according to the display" charge by the following evening - although because of the long absorb charge requirement of our battery bank wiring / size, it may be an additional evening until the battery is truly full and will hold at 13+V at rest after the sun goes down.

7) Haven't noticed any adverse effects on the batteries.  Still showing the same charging patterns, full voltage, etc.  But they are brand new, and it's still early in the high power A/C draw process, so stay tuned!

Anything I'm missing, or any questions?

Two updates:

1) I've continued to see large compressor spikes - even higher than the 400+ Amps I've seen generally.  Given that I doubt the magnum display is "fast" enough to give an accurate reading of the spikes, I'll assume the highest reading I've seen in 15-20 iterations of the compressor turning on (750 Amps!!!) is the standard spike.  That is high enough to make me think the Micro Air is NOT performing as I'd hoped.  It is also high enough to be outside the specs of the Magnum Inverter.

2) As you may know the AUTO setting on the Duo Therm units automatically changes operation from High-to-Med-to-Low the closer the interior temperature gets to the desired thermostat temperature.  I must have been caught in a funky temperature transition today, and the A/C cycled between Med-and-High 3 or 4 times within a minute.  Then (I guess because of the repeated spikes) the Magnum inverter shut down with an "A/C fault."  First time that has happened.  Worth noting that it did not pop the built-in breaker on the inverter itself (which DW did pop once when she tried to turn on every kitchen appliance at the same time....).  In any case, moving forward, I will run the A/C using a constant fan speed (probably Low), and avoid using the AUTO setting.

I'm starting to think that, rather than try to modify the existing A/C unit to be within the specs of your system, it may be safer to buy a low energy A/C that is actually within the specs.  There is a solar company out there that sells a low-energy A/C unit to go along with the solar kits it sells - but my google-fu is lacking this morning and I'm having trouble locating it again.

Great information. Keep us posted as you learn more.

Are you able to run the ac long enough to cool down the coach? How long do you leave it running?

Might try some adjustsable time delay relay on the evaporator fan and condenser fan circuits 5 & 10 seconds might help. Invertor compressor lock rotor (inrush) amps are approximately only 10% more than full load amps. This is the future for RV a/c units. Can you build a 12,000 btuh unit that starts on 10 amps inrush and 900 watt operation? Yes with widely available components today.

I think you are talking about this unit from Kingtec Solar (https://www.amazon.com/Kingtec-Solar-Air-conditioner-Recreatinal-Vehicle/dp/B00K1JLWB6) but it operates on 48v DC power which is going to be a problem for you. 

I find it kind of embarassing at how behind the times the US RV market is regarding this.  Check out Dometic Australia's inverter air conditioner (https://www.dometic.com/en-au/au/products/climate/air-conditioners/air-conditioners-for-rvs/dometic-harrier-inverter-_-78610#features) that probably will never make it to the US market.  Dometic EU seems to have lots of different options that also aren't available in the US.  All the improvements to the US market have been small alterations of the same design as we had 50 years ago.

SEER numbers are bogus ratings that are manipulated by the manf, and ARI. They are established by one off prototypes. EER numbers are less manipulated. Friedreichs makes a 14 eer 115 vac unit

We usually run it for about an hour.  Not really helpful in 95 degree weather, but perfect for getting coach from, say, 86, to a more more reasonable 78-80 right before bed when the exterior temperatures wouldn't allow for the kool matic and a few open windows to accomplish the same.