Replacing small rooftop Air Conditioner - lost trying to find info

[fpmtngal]

Most of the threads I found here doing a search about air conditioners have to do with big rigs and large air conditioners or heat pumps.  Plus anything electrical makes my eyes glaze over and my mind go into neutral.

I currently have a small (16.5’ box, 21’ overall length) travel trailer with a 9K Coleman air conditioner.  It’s now almost 6 years old and the AC seems to be drawing more power to run than it should, I think.  My AC is not ducted.  It’s noisy.  I was thinking of replacing it with the Coleman Mach 10 NDQ, which seems to get good reviews from the noise point of view.  I don’t really need the 13.5K of the Mach 10, since my 9K does reasonably well keeping my small trailer cool except when the temp goes over about 102 (it really struggled at 117, but I don’t think even a 15K would have helped that much then).

The reason I think it’s taking more power to both start and to run is that I recently re-did my 12V electrical system.  I now have three 100Ah Battleborn batteries, a 3000W Victron Multi-Plus Inverter/Charger, and additional solar (370W on the roof along with a 120V portable panel, with the option to add additional portable panels if I need to, roof is out of space).  I know a couple of people who run the same 9K air conditioner on a similar inverter set-up, at least for brief times.  When I tried to do it, the inverter went into overload briefly but did allow the AC to start.  The amount of power it was drawing once it was going was higher than my friend’s reported power consumption also, so even adding an easy start/SoftStart won’t completely help.

My needs/desires for a new air conditioner then are twofold: 1. that it be relatively low power AND 2. it be quiet.

Besides the Coleman Mach 10 NDQ, I thought about the Coleman Mach 1 PS - it’s a 11K power saver air conditioner.  It should work as well as my 9K and would draw less power.  Only I have no idea if it is as loud as my current one, and trying to find information on Airxcel’s website is frustrating, since I’m so clueless about such things.  I don’t know whether the energy savings of the 11K power saver over the 13.5K NDQ is enough incentive to buy it instead of the quiet one.

Can any of you give me some advice about this?  Or give me links to help me get some answers?  Or give me suggestions other than Coleman Mach?

Thanks!

[Kirk W]

2 hours ago, fpmtngal said:

The amount of power it was drawing once it was going was higher than my friend’s reported power consumption also, so even adding an easy start/SoftStart won’t completely help.

Before you do anything else, be sure that all of the air conditioner coils are clean and the veins of the one on the roof are straight with a fin repair tool.

To clean the coils, watch this video. DIY - how do clean RV AC Coils. 

When these maintenance items need attention it will cause the air conditioner to work harder and that increases the current it requires. If yours is now 6 years old and has never been cleaned, I would expect it to draw significantly more power. 

[fpmtngal]

Thanks for the info!  I haven’t cleaned the AC this year, so I’ll try that when I’m not parked under tall pine trees, maybe next week.  Still would like something quieter than mine but perhaps I’ll try to figure that out this fall.

[Chad Heiser]

Air conditioners surge (draw high power for short periods) upon start up to allow the unit to run.  Once the surge is completed, it will run at a lower power draw as it cycles on and off.  The initial surge is what overpowered your inverter.  A larger AC unit will have a higher initial surge and will also over power your inverter and put it into fault mode.  You will not be able to run an RV rooftop AC from your inverter without some type of easy start module installed.  The easy start modules draw lower power over a duration of time upon start up and store that power until there is enough to overcome the initial start up surge of the AC compressor.  They then use this stored power for the start up rather than drawing all that power at once from the power source (like you are experiencing now).  I have experimented with starting AC's with the same inverter you have and I have not been able to get one started without an easy start module installed.

[whj469]

A lot of those stand alone ACs are noisy.

[fpmtngal]

40 minutes ago, Chad Heiser said:

Air conditioners surge (draw high power for short periods) upon start up to allow the unit to run.  Once the surge is completed, it will run at a lower power draw as it cycles on and off.  The initial surge is what overpowered your inverter.  A larger AC unit will have a higher initial surge and will also over power your inverter and put it into fault mode.  You will not be able to run an RV rooftop AC from your inverter without some type of easy start module installed.  The easy start modules draw lower power over a duration of time upon start up and store that power until there is enough to overcome the initial start up surge of the AC compressor.  They then use this stored power for the start up rather than drawing all that power at once from the power source (like you are experiencing now).  I have experimented with starting AC's with the same inverter you have and I have not been able to get one started without an easy start module installed.

Thanks, I wondered if adding an easy start would make the difference.  I think a friend of mine has an extra one he would sell me and I can have it installed in a couple of weeks.  If nothing else, if I replace the AC, I can always have it moved to the new one.

Have you heard anything about the new Coleman Mach 10 NDQ that comes with a soft start built in?

41 minutes ago, whj469 said:

A lot of those stand alone ACs are noisy.

Until I started researching the Coleman Mach 10 Quiet series, I thought all of them were about the same, no matter what size they were.  But it appears the quiet series ACs really are quieter.  I don’t really need the 13.5K for my trailer, but they don’t come smaller (they come in a 15K also).  If I get one of Coleman Mach Power Saver units, I’d probably get the 11K.  It uses less power and probably would be about the same as my older 9K.

[Chad Heiser]

3 hours ago, fpmtngal said:

Have you heard anything about the new Coleman Mach 10 NDQ that comes with a soft start built in?

I am not familiar with that specific unit.

[GlennWest]

Could you make a mini split work? They are super quiet and sip power. Not real knowledgeable about your unit.

[fpmtngal]

7 hours ago, GlennWest said:

Could you make a mini split work? They are super quiet and sip power. Not real knowledgeable about your unit.

I don’t know anything particularly about a mini split.  I know that I would have a mounting problem for anything that doesn’t fit on the roof.  I also have a weight problem - I run around GVWR for the trailer with the current roof-top AC unit.  The replacement units are about 85 lbs so I assume mine probably weighs about the same - I wouldn’t want to go higher than that.

Would they have the big initial surge that AC units have?  Do you have a link where I could find out more about one, including specs like weight, size, mounting options and both peak and running power (don’t know if that’s the way they would refer to it, but it’s how I think about it).  At this point I’m open for suggestions, as long as I don’t go overweight, or draw more power than I have available. My 3 batteries (100 Ah each) are all I have room for.

[GlennWest]

Mine pull between 5-7 amps. No surge. Mine are Pioneer but there are many great units on the market. Highseer.com is where mine came from. Both of mine,12k each, will run on a 2k generator. They don't even grunt. There are several youtube videos showing installations on RVs

Edited June 9, 2021 by GlennWest