Adding second air in back bedroom?

[Jusplainwacky]

I'm thinking of adding a second A/C unit in the back bedroom and plan to do some calculations of how many amps I'm currently drawing and if I would need to upgrade to 50amps if I installed the Polar Cub Mach 8 - 9,200 BTU that draws just under 12-amps on high cooling and 15-amps for heat.

I would remove my existing 14x14 vent and install this.

Before I bought my motorhome, I had a cab-over camper and I replaced the air conditioner on it with the Coleman Polar Cub Mach 8 and my Honda EU2200 ran it without a problem. What I liked about it was that it also had a heating element.

Thoughts anyone?

[The Gritz Carlton]

Go big on A/C (13.5 or 15) and run a separate 120V line you can plug directly into the 120V outlet on the power pole while camping. Much cheaper than converting to 50A.

[16ACE27]

Might be a thread or two on this forum about that exact upgrade..............

[LandKO]

Originally Posted by The Gritz Carlton

Go big on A/C (13.5 or 15) and run a separate 120V line you can plug directly into the 120V outlet on the power pole while camping. Much cheaper than converting to 50A.

I agree.
Here’s how I added a second AC unit.
https://www.thorforums.com/forums/f2...1-a-27171.html

[Mr Sunshine]

Originally Posted by 16ACE27

Might be a thread or two on this forum about that exact upgrade..............

Yes, thoroughly discussed at least once. The search tab will keep you reading for hours!

[Jusplainwacky]

Originally Posted by Mr Sunshine

Yes, thoroughly discussed at least once. The search tab will keep you reading for hours!

This post wasn't so much about adding a second AC, it was more about the Coleman unit and the current requirments.

[Chance]

Originally Posted by Jusplainwacky

This post wasn't so much about adding a second AC, it was more about the Coleman unit and the current requirments.

Based on specifications alone, I’m not a fan of the 9,200 BTU/hr air conditioner because it uses more power than the 11,000 Power Saver or some of the newer 13,500 BTU/hr air conditioners like the Mach 10 NDQ, rated at only 10.4 Amps. Notice essentially no new van uses the 9,200 units even though that may be enough cooling capacity — I’m not sure if 9200 are even in production, or why Coleman doesn’t redesign them to make them much more efficient. It’s crazy that they pull more current than 13,500.

Anyway, since it’s for the bedroom, I would personally try the quiet series, and if you are thinking of sometimes powering with 2200/1800 inverter generator like Honda, I’d buy it with the soft start to limit peak starting current.

As far as electric heat, that should be a common option on many models. See specs below which show heat pulls a lot more current (16 vs 10.4 Amps).
.

[Chance]

P.S. — Note 9200 specs show it draws higher current at 11.7 Amps.
.

[Jusplainwacky]

Originally Posted by Chance

Based on specifications alone, I’m not a fan of the 9,200 BTU/hr air conditioner because it uses more power than the 11,000 Power Saver or some of the newer 13,500 BTU/hr air conditioners like the Mach 10 NDQ, rated at only 10.4 Amps. Notice essentially no new van uses the 9,200 units even though that may be enough cooling capacity — I’m not sure if 9200 are even in production, or why Coleman doesn’t redesign them to make them much more efficient. It’s crazy that they pull more current than 13,500.

Anyway, since it’s for the bedroom, I would personally try the quiet series, and if you are thinking of sometimes powering with 2200/1800 inverter generator like Honda, I’d buy it with the soft start to limit peak starting current.

As far as electric heat, that should be a common option on many models. See specs below which show heat pulls a lot more current (16 vs 10.4 Amps).
.

This is exactly the kind of information I'm looking for. And yes, the 9,200 is still being made - I talked to manufacture today. They stopped making it because of a shortage of parts, but are back up in production.

I wasn't aware of the Mach 10 NDQ, which apparently is new (2021). It appears to be a lot better than the Polar Cub 9200 and it's a lot quieter...and less expensive!

I don't plan to run this on small generator. That is why I went with the polar cub as my honda EU-2200i could run it. However, I installed a "soft start" cap. The Mach 10 NDQ can come with soft start.

I'll have to check this out! Thanks for sharing this information!!

[Judge]

Agree with Gritz and Chance..... go bigger and a newer design.

You can buy a RecPro 15K BTU for $1200 that draws 14A for cooling with only 16A startup draw and 12A for heating.

https://www.recpro.com/rv-air-condit...ith-heat-pump/


if you are going to install something small, you might as well install a 12V A/C Unit.

https://www.amazon.com/dp/B0B36PPFFC...NsaWNrPXRydWU=


https://www.recpro.com/recpro-12v-rv...eid=cc56f21150

[Jimbo56]

Originally Posted by The Gritz Carlton

Go big on A/C (13.5 or 15) and run a separate 120V line you can plug directly into the 120V outlet on the power pole while camping. Much cheaper than converting to 50A.

What Gritz suggests is what I did. In fact the non ducted 13,500 Coleman Mach 3 I added cools the entire coach by itself. Your Hurricane is about same size. And the 13,500 will also run on a 20 amp pedestal plug, leaving the 30a for the coach. It won’t run while on generator but I don’t need it while driving. And we don’t boondock.

[Jusplainwacky]

I was hoping to find an AC that I could add and not have to add another plug or go to a 50amp.

Today I plan to turn everything on inside the RV and see what my amps are. In situations like this, the start-up is the killer, but with the slow start, I might be able to get away with it.

What I said about not planning to go with a small generator...what I meant to say is that I had a cab-over camper and I went with the polar cub because I was using the Honda Eu-2200i and it ran that. I was very please with the unit so I was thinking of going with the same thing in the motorhome. But the one that Chance has recommended appears to be a lot better.

[Jusplainwacky]

Well...I got this information from Airxcel. It appears that the polar cub does take less power.

Specs - Polar Cub 9200 BTU
Capacity (Nominal BTUH) Cooling 9,200
Heating (Electric Strip) (1) 6,000
Electrical Rating 115 VAC, 60 HZ, 1 Phase
Cooling Full Load AMP’s at A.R.I. Standard
Condition
Compressor 6.7
O.D. Motor 1.8
I.D. Motor Low –.7 High – 1.3
Total 9.2 9.8
Feature Equipment Amps Heating (1) 15.2
Running Watts (cooling) A.R.I. Standard Condition
(80° F. DB, 67° F. WB Indoor, 95° F. DB Outdoor) 1180
Running Watts (cooling) Desert Condition (100° F.
DB, 72° F. WB Indoor, 120° F. DB Outdoor) 1300
Running Watts (1) Electric Strip 1800
Compressor Locked Rotor Amps 49
Metering Device Capillary Tube
Refrigerant Charge – R-410A 14.75 oz.
Evaporator Air Delivery (CFM) 300 – High Speed
Generator Size See “Generators” Below
Unit Weight (pounds) 87 lbs. (2)
Use time delay fuse or circuit breaker (U.L. H.A.C.R. Type C.S.A.)
Rated at: Min. 15 Amps; Max. 20 Amps (Without optional Electric Heater)
Min.: 15 Amps; Max. 20 Amps (With optional Electric Heater)
See Product Installation, Operating Manual for proper wire sizes

Specs on Mach 10 NDQ 13.5 BTU
Capacity (Nominal) Cooling 13,500
Heating (1) 5,600
Electrical Rating 115 VAC, 60 HZ, 1 Phase
Cooling Full Load AMP’s at A.R.I. Standard
Condition
Compressor 9.5
Fan Motor Low – 1.2 High – 1.9
Total 10.7 11.4
Feature Equipment Amps Heating (1) 16
Running Watts (Cooling) A.R.I. Standard Condition
(80° F. DB/67° F. WB Indoor, 95° F. DB Outdoor) 1325
Running Watts (Cooling) Maximum Condition
(100° F. DB/72° F. WB Indoor, 120° F. DB Outdoor) 1700
Running Watts (Heating) (1) 1800
Compressor Locked Rotor Amps 54.0
Soft Start Device Up to 70% reduction of Compressor Locked Rotor Amps
Metering Device Capillary Tube
Refrigerant Charge (R410A) 15.25 oz
Evaporator Air Delivery (High Speed) 260 cfm
Generator Size See “Generators” Below
Unit Weight (2) 80 lbs. (2)
Use time delay fuse or circuit breaker (U.L. H.A.C.R. Type C.S.A.)
Rated at: Minimum 15 Amps; Maximum 20 Amps (Without Optional Electric Heater)
Minimum (1) 20 Amps; Maximum 20 Amps (With Optional Heater)
See Product Installations for proper wire sizes

[Chance]

Originally Posted by Jusplainwacky

Well...I got this information from Airxcel. It appears that the polar cub does take less power.

.....cut.....

Thanks for latest specs. It appears Airxcel may be slow at updating their website. Who would have thought?


It’s unfortunate the Polar Cub 9,200 BTU/hr lower capacity A/C requires up to 3.1 Amps for fans/blowers alone, which is close to 50% of compressor Amps. I expect that’s because of its small size requiring more power to move air across coils (heat exchangers). That same compressor in the Mach 10 could bring current down below 8 Amps, making it viable for smaller vans and motorhome bedrooms.

The one thing that jumped out in specs is that Polar Cub evaporator operates at 300 CFM on high, versus larger Mach 10 NDQ at 260 CFM. That suggest to me that Polar Cub may be much louder on high fan speed (probably low also) and that air won’t cool down as much (in degrees) so it won’t dehumidify as effectively.


Regarding running two air conditioners on 30A service, I don’t see why not as long as you don’t have much else running at same time. I powered my A/C and microwave regularly on 30A, and each required a little over 13 Amps under average conditions. Either of these two A/C listed pulls less than my microwave, so total would be less; though I expect your motorhome has a 15,000 BTU/hr A/C presently, possibly requiring 15~16 Amps. Just a guess on my part.

Anyway, breakers should have time delay to handle lock rotor current for a moment, so soft start may (should) not be required. Soft start helps most with generators.

[16ACE27]

Just FYI, I run my 13.5K and 15K regularly on 30 amp without issue as long as nothing else is drawing current. On really hot days I'll switch the fridge to GAS for more buffer room.

[Jusplainwacky]

Very COOL Ted...(no pun intended)....that's good to know.

If you can run both, then I would certainly think I could run the Polar Cub. But if I could run both like you, then I'd rather get a 13.5K...didn't think that was possible without going to 50-amp.

I like the one that Chance recommends...as it is very quiet and although it draws more power, it's not a huge amount more.

I don't know what model is in my coach...except its a Mach 15K BTU.

Here are some readings I took off the coach. Readings are in amps.

Just sitting - 1.2
Air Conditioner - 14.9 (Inrush - 49.3)
Air and Refrig - 17.2
Microwave only 13.7
DirecTV (one TV on) - 1.6

[Jusplainwacky]

Originally Posted by 16ACE27

Just FYI, I run my 13.5K and 15K regularly on 30 amp without issue as long as nothing else is drawing current. On really hot days I'll switch the fridge to GAS for more buffer room.

I'm assuming that you put in a separate breaker? If so, where did you put it?

[Skip500]

Wonder if you could run 2 Mach 10 units on 30 amp?

[Jusplainwacky]

I'd like to add a second air conditioner to my 29M in the back bedroom...if you have done this, I'd like to know how you ran your wires (how did you get down the side walls), where did you put the breaker, and your setup.

I know some of you have done this on other coaches; if you have, you are more than welcome to contribute to my POST as many coaches are similar.

[halfprice]

It's fairly easy but to much to write about. If you want to know how I did it send me a pm with your number and I'll call you to explain

Or go to my thread "Jerry hurricane mods" and start reading at post 3131. Not a lot of detail but it covers the install

Jerry