Hey Guys,
I have an idea for air conditioning. I think it will work but not for sure. I need the advice of you electrical gurus. ;)
I am running a 105 amp alternator on the engine. I am thinking about running a 2000 watt AC invertor to run a 800 watt, 8 amp room air conditioner that sits on the floor. I am figuring double that for start up. I will plumb out the hot air and drain but I'm wondering if this electrical set up would work while driving down the road?? If it does, I will be killing two birds as I can plug in to a pole or run a small gen when camping. Thoughts??
Thanks a bunch!!
Chaz
Chaz-How'ya doin? While that sounds good on paper, and the 8,000btu A/C would run on the inverter-8,000btu just isn't much cooling. I have 3-13,500btu roof mounted Colemans. I usually run the front two with front most aimed at me while I drive (I don't have dash air).
Considering most dash airs are around 25-35,000btu, personally I wouldn't even fool with that 8,000btu-I think you'd be disappointed with it's performance. Good Luck, TomC
One more point-while that 8,000btu may keep the front of the bus cool while sitting, remember running down the road presents a lot air pressure on the front forcing in lots of hot air that has to be cooled. Multiply that if you're running into the sun.
Quote from: TomC on January 12, 2017, 05:38:57 PM
One more point-while that 8,000btu may keep the front of the bus cool while sitting, remember running down the road presents a lot air pressure on the front forcing in lots of hot air that has to be cooled. Multiply that if you're running into the sun.
And, that cool air will gravitate towards the rear while going down the road. The front needs a lot to keep the driver cool. Entertainer coaches will have five rooftops, or 3-4 ton basement airs with a separate A/C for the driver. 8000 btu's won't cut it going down the road, and might not be enough while parked, unless in the shade, and the heat has baked off the engine.
Front windows radiate heat, you will have to overcome that first, I did this by putting a 9000btu window AC below drivers seat in tool compartment, short distance to vents at front seats, only worked during the spring, lvmci...
Close to 4kW coming in the front windows, plus large air infiltration as you drive so it is a losing battle.
I think that electrically this will be marginal long term. A 105 amp 12V automotive alternator might be able to produce 105 amps for a short time at peak RPM, but probably will produce half that at idle and probably will over heat if asked to put out full power full time. I read once that the rule of thumb is 60% of full output continuously, unless the alternator is designed for full load all the time. If you could get 105 amps full time, that's around 1300 watts from your inverter. You'll probably be drawing close to 1,000 watts to run the AC unit (8 amps at 120 volts is 960 watts nominal), so it might work, but if your bus uses any electricity at all you'll be drawing down the batteries, and the alternator will probably have a short life. Add a second alternator and it would probably work OK.
Quote from: lvmci on January 12, 2017, 08:54:00 PMFront windows radiate heat, you will have to overcome that first, I did this by putting a 9000btu window AC below drivers seat in tool compartment, short distance to vents at front seats, only worked during the spring, lvmci...
Yeah, not even close when that's all you got, but let's say that you have a pretty good system (maybe 2-3 rooftops) that just needs a little help at the most extreme heat times -- wouldn't that be good as "extra cooling"? Of course, the best thing to do would be to have a system that makes enough cool that you wouldn't have to have extra or buffer additions around but sometimes it doesn't work out that way.
It would also seem likely to me that if you had a large capacity blower to move that cool air around you'd be doing yourself a favor. But the big principle is "if you don't have enough BTUs of cooling, you're going to be hot".
I can tell you the 10k btu portable unit we used last summer just barely kept up in the spring parked, summer, wife not happy at all, may look into the 15k split 110v this year. I'm trying my best to avoid the roof airs because of the way they look.
Quote from: bevans6 on January 13, 2017, 05:12:34 AMI think that electrically this will be marginal long term. ... Add a second alternator and it would probably work OK.
Brian, every point you make is technically correct but wouldn't the whole thing be a lot of work and expense for very little real-world gain? You're talking about component and installation costs, load on the engine, battery purchase and maintenance costs, etc. for 8K BTU. If it tips the scales between being too hot and comfortable, yeah, I see that, but in most situations, it would seem to be too much cost for the benefit.
Quote from: Nel on January 13, 2017, 05:24:56 AMI can tell you the 10k btu portable unit we used last summer just barely kept up in the spring parked, summer, wife not happy at all, may look into the 15k split 110v this year. I'm trying my best to avoid the roof airs because of the way they look.
I've been using a portable to keep some semblance of cool inside my bus while I've been working through my engine change. The things are just not very good. Once they really start working, they pull air that they've already cooled down into the unit to cool the condenser and then exhaust it out the little hose at the back. So they're cooling air that they then pump out of your living space. If there was some way to rig up two hoses -- one to bring in outside air to cool the condenser, and one to exhaust the air after it had been heated by that function of going through the condenser/heat exchanger -- it should improve things a lot. Even better would be mod that would make it work like "recirculation" on your car; draw in already cooled air to go over the evaporator and cool that air even more before it's blown into your living space so you're not losing so much of your cooled air to air leaks, etc.
Of course, much of this would be solved by a split system. I just have found that portable systems are pretty doggone inefficient.
(Edit:) I just went back to the original post and re-read. It appears to me that's asking about a portable (I was thinking Gary Throneberry's principle of a "redneck" installation of a window air conditioner in the side of the bus). He says "plumb out hot air and drain" but still, a portable has a lot of built in inefficiencies.
We'd like to throw something in here, we have one 13,500 btu roof top on the 4104. When we run it on the genny going down the hwy it keeps us a lot more comfortable than not - no matter what the temps are OS. It also lowers the humidity which is a great help. If the sun coming in the windshield makes it feel uncomfortably warm we throw a drivers fan on - solves that. We'd like to think a 160 amp engine generator (original equipment) would run an inverter to keep from having to run the genny for that A/C. So we feel where Chaz would like to go with the 8000 btu unit (but don't think it has enough cooling) - to keep us on thread.
Quote from: Oonrahnjay on January 13, 2017, 05:32:23 AM
Brian, every point you make is technically correct but wouldn't the whole thing be a lot of work and expense for very little real-world gain? You're talking about component and installation costs, load on the engine, battery purchase and maintenance costs, etc. for 8K BTU. If it tips the scales between being too hot and comfortable, yeah, I see that, but in most situations, it would seem to be too much cost for the benefit.
He asked if it would work electrically, so that's the question I answered. He didn't ask if it would work thermally, and everyone else had answered that already, but no one had said if it would work electrically.
Electrically was answered.
As to the look of the roof top A/C's-you'll notice that the majority of sticks and staples are using roof tops. On the high end coaches, 3-5 are used. What they do is create a side extension of the wall to effectively hide the A/C's and the awnings. You could do that also with the bus. Believe me when I say, roof top A/C's work the best, are easiest to work on. BUT-they are also the noisiest and look bad. Good Luck, TomC
hi Bruce, my window AC install under the drivers seat idea, was to help while driving, with the roof front AC, that was 13 or14' back, it was a front kitchen floor plan, nothing like external ducting, fans, etc, worked in the hot desert. originally tried a wheeled upright portable, with 9000btu, I thought it was to dangerous in an accident, and thought I would get more effecient with the exhaust heat out of the room, lvmci...
Quote from: lvmci on January 13, 2017, 11:55:09 AMhi Bruce, my window AC install under the drivers seat idea, was to help while driving, with the roof front AC, that was 13 or14' back, it was a front kitchen floor plan, nothing like external ducting, fans, etc, worked in the hot desert. originally tried a wheeled upright portable, with 9000btu, I thought it was to dangerous in an accident, and thought I would get more effecient with the exhaust heat out of the room, lvmci...
How many BTUs on the window unit? Did it work well? (I can see how it would being right in the driver's area.) Do you share our inefficiency experience with the portable A/Cs?
Quote from: bevans6 on January 13, 2017, 09:24:46 AMHe asked if it would work electrically, so that's the question I answered. He didn't ask if it would work thermally, and everyone else had answered that already, but no one had said if it would work electrically.
Sorry, I didn't mean to sound critical. And, as I said, you were right about the factors in your post. In my mind, the electrical/thermal part is highly connected, the more un-thermals the more electrical load and the more electrical load, the more electrical issues.
I apologize if my comment came off wrong. BH
hi Bruce, I put two dryer vents to direct the air, on the upright portable AC, so there was constant fan on us, but didn't feel great over 95° and the extra heat created by the exhaust heat tubing was an issue, the window unit was 9500btu, tom...
Dang guys, thanks a bunch for all the info!!
Tom, I'm doing OK. Thank you for asking. Not to dwell on it but, this eye thing has kept me from driving my bus for 2 years. There is no hope to see out of it again so, if I don't get more confident in driving it, she will have to go. It is one thing if I mess up in a car but, if I mess up in my bus, it could be a REALLY bad day for other people. And I am one who does not feel that it is all about me.
I hope all is well with all you folks!! I'm not gone yet.
Take good care,
Chaz
Hi Chaz.
Not that you need additional information, but I had a thought so I'm sharing...
I agree with previous posts on electrical efficiency and cooling capacity. I still have the factory heat/AC (converted to 134a). BUT, if I wanted to pull it all out, I would use the driver's heat/ac and spare tire compartment to add some type of system for the driver.
I have 3 13,500BTU roof air units, but when I'm driving towards the sun, I actually get tan lines from the windshields and even with one unit close to the driver...I'd never know they were there.
So, why not find a system that uses the dash vents and possibly one or two added?
Like I said, just a thought.
some people use a complete auto system, just for the front, but there is package 12V systems, just expensive, lvmci...
Quote from: lvmci on January 14, 2017, 11:12:33 AMsome people use a complete auto system, just for the front, but there is package 12V systems, just expensive, lvmci...
Red Dot??? Yeah, breathtakingly expensive.
Quote from: Oonrahnjay on January 14, 2017, 06:02:47 PM
Red Dot??? Yeah, breathtakingly expensive.
Yeah but you guys don't know Chaz. He can and does an amazing job of scrounging parts and stuff.
Chaz you could go to a junk yard and scrounge up the pieces you need for a dash system probably for less than a $100.
SORRY to hear that your eye damage is permanent!
Good luck on the A/C system and it's good to see ya back here on the board.
;D BK ;D
This is just for the sake of collaborating, but what would be the best way to use the existing in-dash system, and separate it from the coach AC ONLY.
Everything needed for a separate system is already under the dash, save a small compressor, receiver dryer...?
I'm not thinking about affecting the coach heat at all??
Quote from: daddysgirl on January 15, 2017, 09:08:16 AM
This is just for the sake of collaborating, but what would be the best way to use the existing in-dash system, and separate it from the coach AC ONLY.
Everything needed for a separate system is already under the dash, save a small compressor, receiver dryer...?
I'm not thinking about affecting the coach heat at all??
If indeed the original set up has not been removed then yes you would have an evaporator, fan and duct work already in place.
Then you would need to get an compressor, drier, and lines to connect it all. (of course with safety pressure switches too)
Welch Industries in Stockbridge, GA has a nice complete system for coaches that mounts in the rear tat could easily be adapted to the drivers area with longer hoses.
If your keeping your OTR A/C then you don't need a separate system, just fix the fans or whatever it needs.
;D BK ;D
yes the OTR AC should have driver controls and seperate fan, at least the MCIs do, you could also boost the driver fan ventilation, just a suggestion, lvmci...
Quote from: B_K on January 15, 2017, 08:56:38 AM...Yeah but you guys don't know Chaz. He can and does an amazing job of scrounging parts and stuff...
I once had a friend who went to the junkyard and come home with a basket full of parts. All he needed to buy from the auto parts place was a double crankshaft pulley (and he probably could have found the right one of those at the "automobile parts recycler" with a little more time). Within a couple of Saturday afternoons, he had put together an AC system that would run you out of a Dodge Maxi-van with frostbite. Probably a little harder 40 years later with non-polluting Freon, etc., but I'm guessing still pretty easy if you know a little about what you're doing.
You can run some crazy BTU's off a single vee-belt on an engine if it's driving the right compressor and you have the right parts hooked up to it.
The trick deal would be to have this driver's AC system electrically powered, so it can run with the big engine off.
Always another variable to play with?
happy coaching!
buswarrior
Quote from: buswarrior on January 15, 2017, 06:22:12 PMThe trick deal would be to have this driver's AC system electrically powered, so it can run with the big engine off.
Always another variable to play with?
happy coaching!
buswarrior
I talked to Lamar Welch about that a while ago. His take is that it's technically feasible but for enough BTUs to be worthwhile, it would be a BIG, Electron-Eatin motor that you'd have to have to run it. He thinks that it would require a hefty generator running fulltime to do it. Not impossible, but cheaper/lighter/more efficient to get your cold air other ways.
Quote from: lvmci on January 15, 2017, 02:17:05 PM
yes the OTR AC should have driver controls and separate fan, at least the MCIs do, you could also boost the driver fan ventilation, just a suggestion, lvmci...
I still have every part of the OTR system, converted to 134A. Both heat and AC work great, but...How would I boost it for the driver? That would be FAN tastic :)
The other thought was for those who have torn out their OTR systems. I can't imagine driving without it...those darn windshields... BUT I am going to be adding material to the area above the visor, VERY soon.
How to improve driver's air?
Get close control over the outside air vent.
Air intrusion will consume the good you are trying to do with the AC.
happy coaching!
buswarrior
Quote from: buswarrior on January 16, 2017, 09:22:27 AM
How to improve driver's air?
Get close control over the outside air vent.
Air intrusion will consume the good you are trying to do with the AC.
happy coaching!
buswarrior
Also making sure the drivers evaporator is good and clean with free airflow along with a clean filter will help tremendously! I can't tell you how many times I had drivers from other companies complain "my driver A/C doesn't work worth a crap" Only to find it was filthy and needed a new filter. After that it was good to go!
Once in a while they would need new brushes in the motor. (but not often because a working defrost is A MUST so the mechanics would make sure the blowers worked, but would often times either forget or flat out ignore the drivers evaporator & filter)
;D BK ;D
Also check your coils for the evaporator (inside) and condenser (outside) for dust buildup of the evaporator and road grime on the condenser, Clifford showed me how clogged up my radiators were by simply shining a strong flashlight thru one side while I was on the other, I could barely see the light, when I should be able to see it clearly. there is a large spray can available for AC condenser coils, that you spray on and rinse off at hardware stores. Think of it like wrapping a blanket around your water heater to keep heat from escaping, only you would want to take the grime coating the fins off your condenser, TO let the heat escape, lvmci