Custom Air Conditioning Retrofit

[Patandlinda]

Originally Posted by rubicon327

I respect that since your use is minimal and you are already invested.

For the rest of us especially those in warmer climates just imagine for a moment if a trailer manufacturer like Escape took the time to engineer and implement a sleek, split system that

-provides cooling, dehumidifying, heating and fan modes
-is whisper quiet inside and outside
-has inverter compressor technology that reduces amp draw and improves dehumidification versus an oversized constant speed compressor
-provides cooling to 115F, heating down to 15F
-lowers overall trailer height
-creates less aerodynamic drag
-provides for a nicer overall exterior look/profile (especially on smaller trailers)
-has less weight (and possibly the ability to position condenser underneath or where the weight might be desired to positively affect tongue weight)
-provides more room on roof for solar
-no roof opening or opening used for passive ventilation/light or add'l fan
-creates more headroom inside trailer
-auto restart and compressor protection time delay (set EMS on 15 sec delay instead of 2:16 just to protect your A/C)
-no condensate dripping down side of trailer
-easily run on 2KW generator (with no hard start capacitors or SmartStart system to worry about)
-with economy mode (580W) possible to run off inverter tied to lithium battery bank and solar?

Those that want/need A/C deserve better! What's not to love?

Dave no convincing me ! I love it . Only problem I need to win the lottery or something first . Only problem I don't play , not a gambler ,already paid for the AC . Where were you when we needed you ? Pat

[Defenestrator]

Originally Posted by rubicon327

I respect that since your use is minimal and you are already invested.

For the rest of us especially those in warmer climates just imagine for a moment if a trailer manufacturer like Escape took the time to engineer and implement a sleek, split system that

-provides cooling, dehumidifying, heating and fan modes
-is whisper quiet inside and outside
-has inverter compressor technology that reduces amp draw and improves dehumidification versus an oversized constant speed compressor
-provides cooling to 115F, heating down to 15F
-lowers overall trailer height
-creates less aerodynamic drag
-provides for a nicer overall exterior look/profile (especially on smaller trailers)
-has less weight (and possibly the ability to position condenser underneath or where the weight might be desired to positively affect tongue weight)
-provides more room on roof for solar
-no roof opening or opening used for passive ventilation/light or add'l fan
-creates more headroom inside trailer
-auto restart and compressor protection time delay (set EMS on 15 sec delay instead of 2:16 just to protect your A/C)
-no condensate dripping down side of trailer
-easily run on 2KW generator (with no hard start capacitors or SmartStart system to worry about)
-with economy mode (580W) possible to run off inverter tied to lithium battery bank and solar?

Those that want/need A/C deserve better! What's not to love?

As someone full-timing across a variety of climates, this would be amazing. I've got 500Ah of batteries, so mini-split A/C in economy mode could run for 8 hours even at 100% duty cycle. For things like overnight stops in the summer it'd probably be more like 30% duty cycle, so I could just leave it on overnight.

The dehumidification would be a huge deal for longer trips as well. In cold climates a bit of ventilation will do and in hot climates the A/C dehumidifies OK, but in a moderate-temperature humid climate keeping humidity down becomes a pretty big challenge. I've got a little thermoelectric dehumidifier, but it's inefficient and not very effective. The compressor-based ones are just too bulky and for a small trailer it's silly to have two separate ones for A/C vs dehumidification.

Solar room would be great, too. That particular advantage hadn't even occurred to me, but the A/C really does makes panel placement tricky. I bet I could easily fit a third 180W panel on the Escape without it, and quite possibly a fourth.

With the extra room for solar, it might even be feasible for the heat pump to do a lot of the heating on battery power. Especially during the day.

[rubicon327]

Originally Posted by Defenestrator

As someone full-timing across a variety of climates, this would be amazing.

With the Fujitsu mini-split I'm realizing all of the benefits listed except the last one. That is more of a future thought as the cost of lithium batteries and solar continue to come down.

Regarding the dehumidification abilities of the mini-split it has what is called a "dry mode". Fujitsu claims it "allows for moisture removal in low load conditions of up to 50% of rated moisture removal capacity". Since it is rated at 1.3 pints/hr this would mean 0.65 pints/hr or approximately 2 gallons over the course of 24 hours. Just for perspective this seems to be on par with small standalone dehumidifiers.

What really disappoints me is that there are already "RV" split systems that exist but they are not available in 120V, 60 Hz. Dometic makes one that I think I mentioned earlier in this thread. Kimberley (who are reopening) use them in Australia. They don't show the condensing section though.

https://www.dometic.com/en-au/au/pro...on-22-_-136297

[Ron in BC]

Originally Posted by rubicon327

but there are still only 2 in existence in Escapes!

Maybe at least one more pending. But since we don't pick up our new 21 until Sept. any comments on what I what to do may be premature. I'm thinking I may end up with a hybrid of your two installs.

Actually I'm in Calgary for my HVAC nephews' wedding and I'll be asking him about getting me a wholesale price. Guess it would be tacky to bring that up before I offer my congrats.

You've definitely paved the road for the rest of us.

Ron

[rubicon327]

Originally Posted by Ron in BC

Maybe at least one more pending. But since we don't pick up our new 21 until Sept. any comments on what I what to do may be premature. I'm thinking I may end up with a hybrid of your two installs.

Actually I'm in Calgary for my HVAC nephews' wedding and I'll be asking him about getting me a wholesale price. Guess it would be tacky to bring that up before I offer my congrats.

You've definitely paved the road for the rest of us.

Ron

A few have contemplated it but no action so far that I know of. Excited to hear that you may take it on! It's a challenging DIY, but the benefits speak for themselves. I assume that since you are ordering new you will omit the rooftop A/C and save the money. Where are you thinking you would put the condenser?

[Farther]

I, for one, would definitely consider a mini-split if it was an option on the build. I had a Mitsubishi mini-split on my last home that replaced a Monitor heater and window air conditioner and it worked very well. Whisper quiet and dedicated thermostat/unit in each bedroom & living room.

[Ron in BC]

Originally Posted by rubicon327

A few have contemplated it but no action so far that I know of. Excited to hear that you may take it on! It's a challenging DIY, but the benefits speak for themselves. I assume that since you are ordering new you will omit the rooftop A/C and save the money. Where are you thinking you would put the condenser?

Previously I've built my boat holding plate system so I'm hoping it won't be any more challenging than that. But there's always something.......

I was thinking outside, moving the propane tanks aft in a modified tongue box structure and the mounting compressor on the front where the propane tanks were. Inside would be at the rear dinette. But as I said, I better not make too firm a plan until I have the trailer in hand. And I might have a few other mods to do before I get to that one.

Still waiting for a good opportunity to ask my nephew what kind of a deal he can get me.

Ron

[rubicon327]

When looking through the Hymer North America auction I noticed mobile air conditioning units for sale. Then I realized that because of the pop top roof design these are underfloor and are what I have seen just behind the step when looking at a side profile of the trailers. Originally noticed it because of impact on ground clearance. They are described as “MOBILE CLIMATE CONTROL 12V MODEL T13-22601 EVAPORATOR/CONDENSOR/COMPRESSOR UNIT”. I studied the Mobile Climate Control company when researching quiet A/C solutions but they make 12V units for buses and off road vehicles that I believe would typically have an alternator(s) running constantly. Does anyone know how well these might work and if an RV application is even practical?

[cpaharley2008]

never used one but it would seem logical to be only used with electrical hookups, like our stock a/c units.

[rubicon327]

Originally Posted by cpaharley2008

never used one but it would seem logical to be only used with electrical hookups, like our stock a/c units.

Seems odd to have a converter/charger that must run to keep the battery charged up and some really meaty conductors and fusing for a 12V unit. I suppose with the proper engineering it could work though.

[cpaharley2008]

I have a Fujitsu inverter heat pump in my home, it is a split system for 2 rooms that are not serviced with the whole house system. It is very efficient and quiet on both cooling and heating and probably similar to a 12v model.

[John in Santa Cruz]

the smallest models I looked up on Mobile Climate Control's site, (couldn't find any T13 models) draw on the other of 10 amps at 13V. many where way way more than this, like 100 amps at 13V.

edit:
wait, 10 amps at 13V is only 130 watts. that must have just been the fan, not the compressor. AC's tend to be 1500-2000 watts for small units, and many times that for bigger ones.

[John in Santa Cruz]

Originally Posted by cpaharley2008

I have a Fujitsu inverter heat pump in my home, it is a split system for 2 rooms that are not serviced with the whole house system. It is very efficient and quiet on both cooling and heating and probably similar to a 12v model.

how many watts? watts / 12V will give you the amperage a DC version with the same capacity would require.

[Brian B-P]

Originally Posted by rubicon327

... They are described as “MOBILE CLIMATE CONTROL 12V MODEL T13-22601 EVAPORATOR/CONDENSOR/COMPRESSOR UNIT”. I studied the Mobile Climate Control company when researching quiet A/C solutions but they make 12V units for buses and off road vehicles that I believe would typically have an alternator(s) running constantly. Does anyone know how well these might work and if an RV application is even practical?

While a 12V unit could be used that way, it's more typical to drive the compressor directly from the engine. The 12 volt design is normally used to allow cooling while the engine is not running, during trucker's test stops or no-idle bus stops... although it could also be used to handle an unusual off-road vehicle in which engine accessory mounting might be awkward.

A truck cab is small by RV standards, and trucks set up for this carry a large battery set (e.g. about twice the capacity of an Escape's option dual GC2) to enable operation without the engine running. The truck also restarts and drives for 12 hours or so after 8 hours or less of resting with the engine off, so this battery-electric operation doesn't translate well to typical RV situations.

[Brian B-P]

Originally Posted by rubicon327

Seems odd to have a converter/charger that must run to keep the battery charged up and some really meaty conductors and fusing for a 12V unit. I suppose with the proper engineering it could work though.

I agree. If the intention really is just to run as an elecrically-driven accessory it might need a dedicated alternator, and if one is adding that it would make more sense to pick a higher operating voltage to keep the current reasonable. Typical belt-drive mild hybrid systems use about 48 volts.

[rubicon327]

Originally Posted by rubicon327

At about two years now...mini-split wasn’t cooling well in the high temps so I had my HVAC tech friend check it out. Was low on refrigerant. Sniffer on high sensitivity didn’t pick up any leaks on the entire system. We think it was possibly a very slow and intermittent leak from the Schraeder valve on the charge port. We’ll monitor, but it is back to working fantastic with a little R-410A injection. Only if the issue persists will we fully evacuate the charge and pressure test with nitrogen like we did at original start up.

Originally Posted by rbryan4

Thanks for the follow up Dave. I would expect that the system might be a little more susceptible to minor leaks, since it's a home system applied to a moving vehicle. But if all it takes is a little refrigerant every couple of years, no worries. I think you've more than proven it's superiority to the roof mount.

For those that have followed the mini-split install and operation I wanted to disclose that we needed to add a small amount of refrigerant again. It was working perfectly on a trip in late July and then when about to leave on a mid-August trip it wasn't cooling well. No time to fully evacuate and pressure test so we just topped off with R-410A again and it is working great. This is only a very small amount of refrigerant lost over the course of a year but if this happens again I am going to do a full evacuation and pressurize with nitrogen. I may need to use some dye as suggested by another member because it may only be leaking slowly/intermittently when going down the road. The only fittings are at the connections to the indoor and outdoor units. My guess on the leak is where the semi-rigid copper lines come into the outdoor unit. If this is truly the cause I'm hopeful that the flexible refrigerant line connections that I installed on Viator's 21 is going to keep him trouble free.

[Truckasaurus]

Wow, what an awesome thread! My project trailer is a vintage Airstream (1960) and at 33' long maybe I'll need the 12K unit but I have been looking for a well executed solution like yours for literally years.

Thank you for the excellent write up and when I get mine installed and the exterior unit chrome plated or vinyl wrapped in silver I'll post a pic up too :-)

Here's my design mock up from 2016 for your amusement. PS sorry it's not fiberglass

[rubicon327]

Originally Posted by Truckasaurus

Wow, what an awesome thread! My project trailer is a vintage Airstream (1960) and at 33' long maybe I'll need the 12K unit but I have been looking for a well executed solution like yours for literally years.

Thank you for the excellent write up and when I get mine installed and the exterior unit chrome plated or vinyl wrapped in silver I'll post a pic up too :-)

Here's my design mock up from 2016 for your amusement. PS sorry it's not fiberglass

William: Glad you like the thread. Did you watch the videos to hear how quiet it is? I am happy that it is helping people consider alternatives to the current A/C offerings. I may write the new leaders at Escape to stress that they should at least consider the modified Houghton Belaire unit available from Advanced RV that I highlighted in post #329. I'm sure they could easily establish a relationship and procure units. Install would be very similar to what they do now. If any trailer manufacturer, including Escape and Airstream, wants to get innovative and a leg up in the market they could work with Dometic or Mobile Climate Control to develop a split system specific for their trailers. With 70%+ of Escape customers being US based it seems like a no brainer. In the meantime, guys like you and me have a great custom solution if you are willing to think it though and put in the effort. The payoff is huge. By the way, for your size trailer I would definitely go with a 12,000 BTU unit. My recommendation would be the Fujitsu 12RL2. By not oversizing and making it work pretty hard it will dehumidify nicely for you in the south.

https://www.ecomfort.com/Fujitsu-12RL2/p65506.html

[E Ticket]

Dave,

Very very nice work on your Fujitsu mini split project. I can appreciate all the research, trial and errors, sleepless nights and loads of elbow grease. Congrats. Now I see your desire to go Lifep04. Save weight and space and great energy density. You will not regret it. I have over $10k battery invested in my home solar system. I have no regrets.

[rubicon327]

Originally Posted by E Ticket

Dave, Very very nice work on your Fujitsu mini split project. I can appreciate all the research, trial and errors, sleepless nights and loads of elbow grease. Congrats. Now I see your desire to go Lifep04. Save weight and space and great energy density. You will not regret it. I have over $10k battery invested in my home solar system. I have no regrets.

Thanks for the compliment. It's always a little nerve wracking when you start cutting into things and no one has done it before you, but with risk sometimes comes reward. The system has been amazing. I think we are still years away from an "economical" way to power any A/C via batteries and solar but it is fun to dream. The first move is definitely smaller, more efficient (and quieter!) A/C units. The technology is there especially with lithium batteries. We just need the cost to come down and I think we'll start to see this type of thing going more mainstream.