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Searching4321

Posted 2017-02-26 12:02 PM (#4384)
Subject: Keeping Cool

Location: The Berkshires Massachusetts
(72.189.23.12)

Good morning everyone,

The most important creature comfort for Theresa and I in #4 will be a working AC while traveling down the highway. Our system seems to be intact, however not sure how well it will work on hot days keeping the coach comfortable. I have read a lot of forums about running the generator and house AC while driving. This will not be an initial option for us the way it is currently set up. (There was one thread on another forum where owners of newer models of rvs seemed jealous of the older FMCs and there high capacity for cooling). The house system has been modified. The base cabinet "air handler" had been removed and a window type Household unit was mounted into cabinet at floor level. The only way for this system to run will require the under deck storage door to be open for circulation. So, all that said.....

What kind of performance can we expect from the Automotive AC system if it is maintained and functioning properly? Were the hidden lines for this system pretty indestructible, leaving connections, and components as the source of any freon leaks...if there are any or I get any?

Is the original house AC impossible to restore...given the missing component? Can other Roof AC parts, OEM or "will fit", be acquired if needed?

My other concerns revolve around engines running hot, given that running the automotive AC will usually cause an engine to run warmer. Is this a valid concern with the 440?

Previous owners had some engine temperature issues that had been ironed out. Are there alternative methods/modifications to help these run cooler in general? There are outboard fins on both side access panels to the engine, and there is one exhaust manifold that is the downward type.

John

BigRabbitMan

Posted 2017-02-26 1:04 PM (#4385 - in reply to #4384)
Subject: RE: Keeping Cool

Location: Cottage Grove, OR
(166.137.246.49)

The original automotive system does not work in most coaches at this point as there are too many connections of an old style for which there no compatible parts available at this time. Given the modifications to the house system, I would recommend simply going to a modern roof mounted AC unit. They draw less current and work very well as they are cooling the hot air at the top of the interior. That would just leave the question of one or two units. Either one in the center area of the coach or one in the forward area and one in the bedroom area.

I would therefore recommend removing the roof top condensers and installing two smaller roof top units. You would then run the generator when travelling and using the AC, but that is done by many. I run my generator with my two original AC units when needed. I have attempted to have my auto AC repaired several times, but it still does not work. You can do the original house AC systems if you can locate one or two working units that have been remove from a coach and not disposed of. That would be the simplest if you can locate them. Try a post in Traders Market section of this website. I do like the cleaner lines remaining by using the original units.

LCAC_Man

Posted 2017-02-26 4:27 PM (#4387 - in reply to #4384)
Subject: Re: Keeping Cool

Location: Oceanside, CA
(172.10.134.245)

I agree with all that Stephen said. I completely gutted every component of the automotive A/C system; I was fortunate that a previous owner had already removed both of the original house units and installed a single roof A/C(then converted that empty space to storage). I have since replace that unit with a lower profile (13.5kbtu) model and installed a second roof (9.2kbtu) A/C just behind the passenger seat position. I can easily run them both off my generator but my primary method is to just run the forward 9.2kbtu unit off my inverter, allowing my second engine driven high capacity alternator and large house battery bank to power the inverter. Many ways to get it done, but, two roof A/C's is a great set up. I purchased Coleman Mach 8's, they are only 8" tall so they don't spoil the look of the coach.
If you start at this picture and go for about 10 more you'll see my install of the new roof top units: http://www.fmcowners.com/mbbs22/photos/show-album.asp?albumid=127&p...

BigRabbitMan

Posted 2017-02-26 11:00 PM (#4390 - in reply to #4384)
Subject: Re: Keeping Cool

Location: Cottage Grove, OR
(166.170.5.20)

I do want to add one thing. When you add roof AC units, be sure to retain at least one roof vent. That allows you to exhaust hot air when you are parked and the outside has cooled off. Much nicer to simply exhaust the warm air rather than run an AC unit. It also brings fresh air into the coach.

5Dollar

Posted 2017-02-27 1:01 AM (#4392 - in reply to #4384)
Subject: Re: Keeping Cool

Location: Bethune, SC
(204.116.151.110)

If you want to rebuild the original auto air completely, particularly if the condensers are on the roof, be financially prepared. I had a mobile air conditioning specialty shop in Smyrna (Atlanta), Auto Cool, redo mine including a new rotary compressor replacement for the original. This place does regular autos, customs, hot rods, semis, dash air in motor homes from all over the Southeast. Not inexpensive, but very good. The cost to get mine working better than new was just over $5,000. For all they did, that was reasonable.

Personally, I would have just put in two low profile roof heat pumps on the roof. One on the front part of the roof and one where the center vent is, or possibly a little further back. I am going with an 11.5K btu in the front and a 15k btu in the rear. Overkill, but incremental cost is small. FMC 589 with revamped auto air will be for sale soon. I am finishing FMC 920 with the roof heat pumps.

Henry

Searching4321

Posted 2017-02-27 6:37 AM (#4394 - in reply to #4384)
Subject: Re: Keeping Cool

Location: The Berkshires Massachusetts
(72.189.23.12)

Thank you all for your expertise and advise. I suspect I will go with roof top models to replace original roof system that was canabilized at the base cabinet. I have been married 33 years. If there is one thing I learned...you can never have too much storage space. Lol

However, I have not decided about the automotive system yet.

I like Len's method, running front roof mount off of inverter... I suspect I could do the same if I removed my AC compressor from my 440 and installed an alternate power supply there.

I may have to swing by Bethune on my trip North...do you give nickel tours Henry?

John

5Dollar

Posted 2017-02-27 6:52 AM (#4395 - in reply to #4384)
Subject: Re: Keeping Cool

Location: Bethune, SC
(174.255.135.90)

Anyone is welcome in Bethune anytime. Remember that Len has a Duramax diesel in his coach. Another alternator on a 440 would be interesting to see. My shops are on US 1 North and my Bethune shop has 2 electric hook ups.

Just give me as much notice as you can that you want to stop by.

Henry

Searching4321

Posted 2017-02-27 7:11 AM (#4396 - in reply to #4384)
Subject: Re: Keeping Cool

Location: The Berkshires Massachusetts
(72.189.23.12)

Thank you for the invitation....I will keep you posted. Currently planning on heading North at the end of the week. I am aware of the Duramax that Len has, impressive transformation. I would imagine a charging supply in place of the big compressor would fit quite nicely on the 440. I also suspect it would help to keep the engine compartment a little cooler.

My only concern with not having an automotive AC would be the defrost mode. Typically AC runs when in defrost mode on newer equipment to expedite clear view glass.

LCAC_Man

Posted 2017-02-27 7:22 AM (#4397 - in reply to #4384)
Subject: Re: Keeping Cool

Location: Oceanside, CA
(172.10.134.245)

As Henry mentions, I am running a Duramax, so it is a bit different, but, not prohibitive. If you remove your A/C compressor and install a second (high capacity) alternator the belt layout won't change too dramatically. Making/sourcing the brackets will require some leg work, but, the electrical aspect is really simple and will allow you to remove the battery isolator and clean up some of the rats nest of wiring in the engine bay.
When I say "high capacity", I'm not fooling around, you'll need an alternator that can continuously put out 130amps at idle rpms, my second alternator is a 270amp unit from DC Power Inc https://www.dcpowerinc.com/fit/Chevrolet~Silverado-Classic~2007~6.6L... they were on sale last year and I paid cash so I got a decent discount but as you can see this stuff is pricey. The inverter needs to be oversized as well, I run a 4000w AIMS unit- http://www.invertersupply.com/index.php?main_page=product_info&cPat... this will also allow me to expand into solar later on.
Finally, you'll need a substantial house batter bank to absorb the Locked Rotor Amps (LRA) spikes during the cycling of the unit on hot days. My battery bank is 580ah and made up of 4 each Power Safe SBS145F batteries https://www.power-solutions.com/batteries/enersys/powersafe-sbs/sbs-... I got them lightly used so I paid ($525) just less than the going price of one new for all four.
Two new roof units: $1700
New Alternator/Mounting/wiring- $1000
New Inverter-$900
New House Battery Bank-$750
So you're looking at something close to $4000 to go the route that I did, cheaper AC units can be had for a savings (they'll just stick up more) but I think you'll struggle to find savings on the rest. I also did all the work myself, if you have to pay to have this done you're probably looking at another $2000..

Just saw your question about defrost...my coach wasn't wired to pair A/C with Defrost so it was no loss, removing the automotive evap coil from the heater box really improved the air flow through the unit so in defrost mode it really puts a lot of air on the glass.

Edited by LCAC_Man 2017-02-27 7:30 AM

Duramaxer

Posted 2017-02-27 1:51 PM (#4406 - in reply to #4397)
Subject: Re: Keeping Cool

Location: Oslo Norway
(84.213.61.97)

Interesting alternator and battery combo you have there Len. Looks like top shelf stuff.

How is the charge regulated, are you going with an advanced regulator or alternator to battery charger.? What is the recommended maximum charge current for those batteries? IF your alternator rpm and cables are up for it you might be cooking of those batteries at the "normal" ,25 charge factor for closed lead acid's.

As always, Stay cool!

Kjetil

LCAC_Man

Posted 2017-02-27 4:40 PM (#4410 - in reply to #4406)
Subject: Re: Keeping Cool

Location: Oceanside, CA
(70.183.105.121)

Duramaxer - 2017-02-27 11:51 AM

How is the charge regulated, are you going with an advanced regulator or alternator to battery charger.? What is the recommended maximum charge current for those batteries?

These batteries are spec'd to get 13.75vdc for a float charge(15.3 for equalize), I am putting 14.3vdc to them now(internally regulated alternator) when the engine is running and no particular load is applied, I need some warm days to see what kind of voltage pull down I get with the A/C loading it for extended periods. I have talked to the guys at DC power and they are willing to change the voltage regulator to whatever I want, but, they said that unless you're on the road 12hrs a day for huge periods of time with no load on the system, you won't be hurting the batteries at that voltage; as most of their customers run AGMs and they have a great reputation I tend to believe that. If I was leaving it plugged into shore power and putting that voltage on continuously with no load I'd be more worried.
When on shore power the inverter uses it's internal multistage charger that was designed for AGM battery charging, so I don't have any particular concerns about that.

Duramaxer

Posted 2017-02-27 6:43 PM (#4412 - in reply to #4410)
Subject: Re: Keeping Cool

Location: Oslo Norway
(84.213.61.97)

Ok. You are having some drop from the full 14.8v then and that's probably a good thing. You are a still a little high for float I would say, so keep track of their temperature and you'll be fine.

After all there is nothing we can do to a battery that doesn't slowly kills it.

Keep the lead cool

Kjetil

LCAC_Man

Posted 2017-02-27 7:23 PM (#4413 - in reply to #4412)
Subject: Re: Keeping Cool

Location: Oceanside, CA
(172.10.134.245)

Duramaxer - 2017-02-27 4:43 PM
Ok. You are having some drop from the full 14.8v then and that's probably a good thing. You are a still a little high for float I would say, so keep track of their temperature and you'll be fine.

Yes, a good battery monitoring system is on my "list of things to do"...we won't talk about the volume of that list.

Searching4321

Posted 2017-02-27 7:46 AM (#4398 - in reply to #4384)
Subject: Re: Keeping Cool

Location: The Berkshires Massachusetts
(72.189.23.12)

Thanks Len.
The end game would eliminate two separate obsolete systems, plus set me up for solar, seems like a win to me.
Do you think the two alternators would kill the 440, or cripple it slightly?
You think I could keep my original alternator, and add one big one in place of compressor?
I was thinking the compressor swap for alternator would be an even exchange of draw on the engine.
Too bad we couldn't retrofit an inline (driveline) generator braking system to harness all that energy when braking.
Or a driveline alternator that feeds off the turning driveshaft.
John

LCAC_Man

Posted 2017-02-27 8:20 AM (#4399 - in reply to #4384)
Subject: Re: Keeping Cool

Location: Oceanside, CA
(172.10.134.245)

I think you're right on- the alternator for A/C compressor swap would be a wash (probably a slight reduction) in engine loading, and yes, keep the original alternator for the chassis batteries and just a new oversize unit for the house system.
If you swap to an allison transmission there is the option of PTO driven components, but, that gets even more complex/expensive.

byegorge

Posted 2017-02-27 12:05 PM (#4403 - in reply to #4384)
Subject: Re: Keeping Cool

Location: Olympia, Washington
(73.42.182.228)

Another point on the factory HVAC system, it has NO provision for fresh air. It is permanently set to recirculate, any moisture (wet carpet, dog water etc.) near the heater will soon be fog on a cold windshield. An operating AC (engine driven or roof mount) would help to dry the air and reduce window fogging.

5Dollar

Posted 2017-02-27 12:29 PM (#4404 - in reply to #4384)
Subject: RE: Keeping Cool

Location: Bethune, SC
(204.116.151.110)

I will be here. Give me a call when your plans are firm.

Henry

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