Inverter/ a/c question

[OneLapper]

My coach has a Coleman roof mounted a/c unit that works fine. The over the road a/c unit is dead and missing parts.  My coach as a crappy gas generator that the previous owner installed in lieu of the diesel unit that was in it at one time.  It also has an inverter that is connected to the engine starting batteries and has no house battery bank.

Here's the question.  Should I attempt to run the roof a/c unit off of the inverter (if it will, I don't know the output but it has a 150 amp breaker) and a bank of house batteries while travelling OR should I install my 5500 watt John Deere gasser genset to run the a/c? The gasser unit will run about 5 hours on a tank, but I'm certain that I would have to put a real tank and fuel pump to make it more convenient to use.

I would like to pickup a used diesel genny but I just sank alot into the radiator, new tires, bearings, seals and brakes.  I do have a pair of Yanmar 3 cyl 27hp engines off a John Deere commercial mower, but the time and money involved in making a diesel generator is probably more than buying a used one, plus they would be pretty noisey unless I enclosed them.

Thanks,

Mark

[Nick Badame Refrig/ACC]

Mark,

Need more info, What size is the inverter?

You will need at least a 2000w inverter to run 1 roof A/C and enough altenator to replenish battery bank.

I think it's always better to run A/Cs off a genset if you don't have bus air!

Nick-

[tucsontattoo]

Mark   I've been wrestling with this problem for a month or so now. I have a 4106 that was set up for boon docking back in the early 90's. It has what was the best stuff of the time but was set up for alto cooler climate than here in AZ. while I do have a 2000 watt inverter and 6 traction batteries for the house and 2 D8s for starting, also coupled to the house bank, the coach was not set up to run the roof top air units (also Coleman) off the inverter. My air only runs off the gen set or shore power. I could change this but 2000 watts is the bare minimum for one roof top unit. I have what is called a pulse air system. I can set a switch to run just the front air or just the back air or, pulse. This switches from one unit to the other about every 10 or 15 minutes. Even at that I've seen my amp meter peg 20+ amps if i have the converter charging and one air running. Now that being said,what I have found is running the front air for driving is not enough air conditioning. when you figure the ware and tare on all those components just to have feeble driving air its just not worth it. Think about it, your running down the road with your gen set burning fuel, cycling your expensive house batteries through your incredibly expensive inverter/charger running one roof air and still sweating. all that stuff has a finite service life and this amounts to burning the candle at both ends.I believe the best option would be to run an automotive type engine driven compressor and a duel evaporator/blower system. Very affordable, alto more cooling and you can leave all that other stuff turned off until you really need it
  Just the decision I've come to, For what it's worth. Hope it is some help.
  If you think this makes sense I would be happy to share what I've found on the subject. Have a friend going the same route in his senicruser.


                                          Good luck   Tucson

[belfert]

amounts to burning the candle at both ends.I believe the best option would be to run an automotive type engine driven compressor and a duel evaporator/blower system. Very affordable, alto more cooling and you can leave all that other stuff turned off until you really need it
 

What auto type air system did you choose?

I talked to Dan Hard air conditioning about a dual evap system, but the cost was over $2000!  The system I looked at also had heater cores, so that added a little to the cost.  The driver's evaporator alone was $700.  My plan is to pull out the current driver's evaporator and install a replacement.  The duct work is all there already.  The second evaporator was around $400, the condenser was $750, and the compresser was $300.  The sales guy recommended a powered condenser instead of one that mount in front of the radiator.

Brian Elfert

[Buffalo SpaceShip]

Mark, we're able to run a 13.5k BTU rooftop air off of our mod-sine 2500w interter w/o too much sweat (I also have a Link panel on the inverter for checking such things).

Many of these coaches have a mongo alt. (150-250A 12v or 24v) that's not doing a whole lot since the blowers and coach A/C are usually long gone. Pressing the alt. into occasional service through an inverter for moderate air conditioning demands will likely be very doable for you as well. Check your inverter specs. Make sure you have adequately BIG wiring going to the inverter from the batts and alt.

If you're running through the Mojave in August, you'll need more juice than any inverter/alt. can provide and more A/C units than one. You'll eventually want a water-cooled diesel 1800rpm genset also, (6kW or more) if you put down enough miles every year in harsher weather and/or boondocking. I, for one, have BTDT one too many times with gasoline gensets and... never again. Too much maint. and headaches with dual-fuel for me.

Also, build yourself a house batt. bank (with 4-6 6v golf carts perf.) or you'll kill your 8Ds in short order. Those batts are not designed for even moderately deep discharges. Even if you don't kill 'em the first (or fifth) time, you're one good discharge away from not starting your bus!

This is an expen$ive hobby, no doubt. And you can pay it now or pay it later... but you'll pay it.

My $0.02,
Brian Brown
4108-216

[tucsontattoo]

Brian   who were you replying to?   I have 6 traction (golf cart) batteries + 2 D8 that are isolated. Never really pull them down too far as we keep the solar on most of the time here in sun country. As for the other fellow, 2000 dollars isn't that bad when you consider the cost of a decent inverter and I think the powered condenser is way overkill, just add a water mister to your radiator. Hotrod air has some pretty nice duel evaporator systems complete for under 2000. One in the dash and one under the dinette and your in business. we are currently on the hunt for a minibus system as per Nick's advice. Would defiantly be a better way to go if we can find one. Anyone out there happen to know where shuttle busses go to die?
   Not trying to say you can't do it that way, I'm sure you have enough alternator.Just seems like alto of generating/storing and inverting just to run a weak air conditioner. 

[OneLapper]

Hi guys,


I'm still in the planning stages of this whole project.  The house systems in this bus leave alot to be desired.  It all seems to be there, though:  roof a/c, inverter, generator.  But...  the genset is a gasser, the inverter runs off the bus batteries, the water tank is a tupperware style 10 gallon container, grey water tank is a 55 gallon drum that was designed to dump on the ground, 5 gallon hot water heater, etc.

Thanks for everyones' input.

Mark

[FloridaCliff]

Mark,

On the "Sunny side"

Even though its not what you may want to end up with, you can still use it untill you upgrade

Cliff

[DrivingMissLazy]

My coach has a Coleman roof mounted a/c unit that works fine. The over the road a/c unit is dead and missing parts.  My coach as a crappy gas generator that the previous owner installed in lieu of the diesel unit that was in it at one time.  It also has an inverter that is connected to the engine starting batteries and has no house battery bank.

Here's the question.  Should I attempt to run the roof a/c unit off of the inverter (if it will, I don't know the output but it has a 150 amp breaker) and a bank of house batteries while travelling OR should I install my 5500 watt John Deere gasser genset to run the a/c? The gasser unit will run about 5 hours on a tank, but I'm certain that I would have to put a real tank and fuel pump to make it more convenient to use.

I would like to pickup a used diesel genny but I just sank alot into the radiator, new tires, bearings, seals and brakes.  I do have a pair of Yanmar 3 cyl 27hp engines off a John Deere commercial mower, but the time and money involved in making a diesel generator is probably more than buying a used one, plus they would be pretty noisey unless I enclosed them.

Thanks,

Mark

Mark, what do you plan to do once you get to your destination? The inverter will then be of no use to you. I suspect you will be boon docking some and you will need a decent genset to run the A/C unit for longer periods of time. And one A/C unit is typically not enough to do you any good in hot climates.

My recommendation is get rid of the construction genset and get a diesel unit designed to operate in a coach.
Richard

[tucsontattoo]

I agree with Richard, Get the gen set and house batteries right first then you can think about the other stuff while your having fun in your bus!!.If I had a diesel Generator and a 3000 watt inverter I wouldn't be worrying about driver air right now. Two roof tops running at the same time would be adequate. My present Generator is propane, one step above your gasser,and my inverter is on the small side.The cost of changing both of those would buy me allot of diesel ,and charcoal for the grill.  What do you have for an inverter/charger. Found some really good deals on refurbished stuff from a place on line. I mean around half price for top of the line units (would send you a link here but would loose my letter) Also I'm using traction Batteries from Sam's club and there doing fine, saved some money there! Have some friends that are going on 5 years with theirs. I think I would definitely look into a Generator head for one of those Yamatas too. Unless you buy one of the new (big bucks) quite diesel gen sets your going to have to build a sound box around the thing anyway.

                     Tucson             P.S. let me know if you want me to send that link and I'll dig it out of my well thought out filing system

[DrivingMissLazy]

I agree with Richard, Get the gen set and house batteries right first then you can think about the other stuff while your having fun in your bus!!.If I had a diesel Generator and a 3000 watt inverter I wouldn't be worrying about driver air right now. Two roof tops running at the same time would be adequate. My present Generator is propane, one step above your gasser,and my inverter is on the small side.The cost of changing both of those would buy me allot of diesel ,and charcoal for the grill.  What do you have for an inverter/charger. Found some really good deals on refurbished stuff from a place on line. I mean around half price for top of the line units (would send you a link here but would loose my letter) Also I'm using traction Batteries from Sam's club and there doing fine, saved some money there! Have some friends that are going on 5 years with theirs. I think I would definitely look into a Generator head for one of those Yamatas too. Unless you buy one of the new (big bucks) quite diesel gen sets your going to have to build a sound box around the thing anyway.

                     Tucson             P.S. let me know if you want me to send that link and I'll dig it out of my well thought out filing system

One of the nice things about this new board is that after you post a message you can go to the modify button and add something, or change it, like adding a link.
Richard

[OneLapper]

Tucson,

I agree.  I haven't priced out a diesel genset new or used, so I don't even have a reference price on them, but that would be the best place to start and build from.  I may as well start looking into using one of my Yanmars, even if it's on the big side.   I'll have to remove the inverter to get the specs on it, right now it appears to be bolted in.

Cliff, thanks for the advice on looking on the "sunny side" of things.  So far I'm having a blast working on it.  My wife okay'd the budget to get it "safe and reliable", and my young daughter loves going for our local rides in it.  My first "trip" is my sister's in VT, about 300 miles.  I know lot's of people and John Deere dealers along the way!  Safety in numbers!!

I really appreciate all the info, guys!

Mark

[Ross]

My first "trip" is my sister's in VT, about 300 miles.  I know lot's of people and John Deere dealers along the way!  Safety in numbers!!

I'm in Sunapee, NH.  Probably not far out your way regardless of which route you take to VT.   

[NCbob]

I guess the topic is Inverters Vs. A/C  but a Construction type generator got thrown in with the mix and that's what I'd like to speak to...the generator that is...  because people have the mistaken inpression that because it's a generator it is built to run under most any conditions...and people die as a result.

Let's assume that an individual takes a Construction type generator and encloses it in a bay and connects the proper wires in the proper fashion and fills the tank...pulls the rope (or starts it electrically), closes the door and starts the A/C.  Then starts the bus, the generator is properly secured so it doesn't bounce around like a B-B in a boxcar, and starts up the road.

I see two problems immediately.  #1, where is all that CO going to go?  #2, How is that poor generator (which cost somebody some big bucks at one time) going to get cooling air.  It's going to overheat for lack of circulating air and seize up, fry or catch on fire.  Not a pleasant scenario.

Let's go back to #1.  Assuming it is running in it's little box and CO is accumulating. The bus is parked.  Upstairs there are fans (from the A/C's) creating the most beautiful Low Pressure area one could imagine.   Everybody goes to bed.......and they don't wake up.  The Sheriff of the State Police find the bodies the following morning.  Those who aren't dead soon will be unless CO poisoning is determined immediately and massive amounts of O2 are administered to bring them around.

My point, friends, is that Construction Generators have no place on a Motor Home, a Bus or an enclosed trailer.  Should you wish to hook it up and set it away from wherever you're sleeping...I have no problem with that.

I guess, the bottom line is: Is it worth it to use a piece of equipment for recreation (which wasn't designed for the purpose your intending to use it) if it's going to cost you your life?

Buy equipment specifically designed for the use intended or leave it at home!   Life is too precious to waste!

FWIW

NCbob

[Kevin]

Hey Mark,

I have a '60 GM 4104 with four deep cycle six-volt Trojans for house batteries and two 8Ds for coach. I have a 2,500 watt inverter and a 230 amp alternator on coach engine. The coach and house batteries can be tied together via switch on dash to solenoid, in order to charge the house batteries while rolling down the road. My generator is not yet installed. We are leaving for the coast Sunday the 4th. I want air!

Yesterday I tried plugging the A/C (Dometic 13,500 low-profile roof air) into the inverter, switched coach and house batteries together to get charge from coach engine alternator and, after bumping up the idle, switched on the A/C. The coach engine rpm dropped for a sec but picked right back up and the A/C blew nice and cold. I let 'er run for about 10 minutes and walked back and touched the inverter's cooling fins. (It is an 80's vintage Trace Engineering 2,500 watt) They were warm to the touch but not hot. The auxilary cooling fan built into the unit did not run, as if maybe it wasn't needed.

Anyway, I'm going to give it a whirl this weekend, for better or worse. I think I read somewhere that this is okay to do if one does not have coach engine or genset driven A/C, but it is probably necessary to have a bit of a house battery bank, and not just the coach starting batteries. I guess we'll see how our house batteries look after our two-and-a-half hour drive to the beach! I hope they are good and charged!!! I also hope my alternator doesn't melt down all over the engine block. Ahem. That would be a drag. Wish me luck, and the same to you!

Kevin