Confirmation on power scheme for MC9

[TheHeavenlyChillbillies]

Hi All.
First time posting   Last October we bought a 1986 MCI MC9 Gladiator II that runs on WVO (waste vegetable oil) and traditional diesel.  We bought it in Portland, OR and drove it home 2600 miles to Buffalo, NY.  With the exception of the fuel pump going and a small part of the WVO system breaking...we got home without incidence.

A recent visit to the mechanic is giving us a $3800 bill to get her NY state inspected and that price includes 6 new tires...so all in all she seems like a great investment so far.

It also came with the seats gutted and 5 separate bedrooms already built so she us perfect for what we're doing....which is touring as a band.

Any how...
We are leaving for an 11 day tour in 3 weeks in the Southeast and I have been tasked with making sure the rooftop AC is working for the trip.  Let me preface this buy saying, that although I would love to buy a Magnum inverter and a mini split AC...we are on an incredible tight budget because of the aforementioned mentioned tires.  Let me also say that my main concern is A/C whole she'said running and some small appliances...mainly a few laptops, phone chargers, and a Keurig coffee maker.

So here's what I have so far...or will be getting in the near future:

-A 24vdc, 8k watt low frequency, pure sine, split phase inverter. (Power Jack...yeah I know...)

- 6 or 8,  12v 110ah Deep Cycle Batteries I plan on running in a 24v bank (I have access to a large number of these batteries that have been lightly used on solar arrays...some for only a few hours, for a really low price)

-the existing roof top A/C that the previous owner installed.  I do not know specs off hand but let's just say it 16k BTUs and 13.5 amps...which seems on the high side of average for a 110v rooftop A/C unit.

-I'm mostly sure I have the 50dn 24v alternator but will verify before I put everything together.

- I do not have a working generator on the bus but I did purchase an older Onan RV generator recently for $100...just  not sure if I'm gonna have time to get it running and tuned up before this trip.

I am aware that I will only be getting half of the power from the inverter because I am doing split phase at 110v.  I am also aware that this brand of inverter has a poor reputation.  I payed $250 for it...and if it can do half of what it claims I should be OK.

Anyhow...here are my questions.

Theoretically...given the specs of the alternator, batteries, inverter and A/C...  This should work right?

It seems to be that the inverter (brand) may be the weak link in thus chain...if so can anyone recommend a 24v inverter that will comfortably run the air conditioner, at a reasonable price. (< $500).  In the future I will get a Magnum or high end inverter....right now I need something that'll get the job done for a few weeks.

My concern is damaging the generator...how do I protect from that?

Is there a better, cheaper, easier way to run the A/C?

I have been reading about this for weeks...I just need to get all of my questions in one spot for verification.  Thanks in advance for everyone's help.

That's all I have for now.  Thanks in advance for the help.

[scanzel]

If you are on the road and don't have the original bus ac system still then yes you will probably need the rooftop unit but no battery bank and inverter will run the ac for very long before the batteries need charging so this is where a good generator is needed to run the ac/ac's while driving down the road. I spent the money on my over the road air to get it fixed, expensive yes. I figured that if the otr air gave out I could still use generator to power the two roof tops while driving. So basically I have a backup system for otr air. Not everyone has this choice but if the generator quits while on the road you now have nothing.

[LuckyChow]

I'm not sure where to start, so I'll just say your plan could work, but appears very risky because you haven't given us any indication that you:

•   Know how to size DC cabling suitable to match battery and inverter requirements with distance
•   Know anything about battery chemistries
•   Know anything about mixing battery chemistries with your engine start batteries
•   Know the maximum charge rate your house bank will accept
•   Own a proper crimping tool for 4/0 cable
•   Know what a Class C fuse is
•   Know that a single roof top A/C will not cool a bus if it is over 80 degrees outside
•   Know that installing an RV generator in a bus may require considerable planning to provide proper cooling, exhaust handling, not to mention fueling.
•   Know anything about a floating ground.

Is there a better, cheaper, easier way to run the A/C?
Better = yes, cheaper = probably not, easier = probably not

These issues are not meant to discourage you, but you should know about these things to do what you are contemplating in a safe manner.  None of us came here knowing these things, but we spent considerable time studying them and learning how do it properly and safely from others.   

[TheHeavenlyChillbillies]

Edit: duplicate post

[TheHeavenlyChillbillies]

Edit: Duplicate

[TheHeavenlyChillbillies]

Ok.  That list gives me a good starting point.  I found a good site that is telling me about battery isolators, circuit breakers, wire guages, etc.  Let me put a more specific plan together and I'll return with specific questions if I have them.

I am was told by the previous owner that the rooftop air helped some.  At thus point I'm just hoping it will.keep it bearable.  I'm asking him now what the status of the original AC was.


Let me ask a few follow up questions to help further direct me.

If I only want the a/c to be running while the engine is...  Do I need a ton of house batteries?  It seems that they aren't doing much.  For the most part, when the bus is parked I can plug the actual a/c directly in to shore power.

[buswarrior]

For my money, in this situation...

Time to be ruthless, you don't have time or finances...

You aren't a busnut in this situation, you are "in business", you don't have time or need for elegant foolishness that wastes your time and resources, and FAILURE is not going to be well tolerated like a busnut forces their spouse into; the spouse usually has other things to count as positives in the relationship against the otherwise abusive conditions some of us inflict on them with our "designs and engineering"...

In other words, if you will forgive the brutality: the band don't want no BULLSHIT...

Forget the deep cycle batteries, you don't need them going down the road, and you can't buy enough, nor put the systems in place in time to use them sitting still, and you'll destroy them, cuz you don't know and don't have the stuff to not blow the money.

The good news? The inverter, with proper wiring and fusing/breakers and you are ready to go using the coach's own batteries. The coach batteries better be of known good condition, otherwise spend good money here.

Like a religion, if the coach is off, so MUST be the inverter, or you are walking home....

I expect the band will NOT be happy with one roof air, not enough capacity, but something is better than nothing.... run the coach on high idle when parked, so the alternator makes good power.

The coach AC system needs somewhere 25 lbs of refrigerant, and if it is empty now, it will be empty at some time again, no telling in how long? Get the previous owner to cut the BS and tell you the truth how long it took to leak down. Then you can decide whether filling it to last a day/week/month is worth your money.

In the limited time you have left, if the roof hatches are not equipped with the stock props and clips, rig up some props and securement for the roof vents so they will withstand being propped open with the hurricane winds of highway speed. Then you have a plan for WHEN the rebellion of the band requires more airflow inside.

The other ruthless way to go is with a generator shoved into one of the bays, and just run it going down the road. Cooling, fuel and exhaust management being critical. Poor cooling, you blow up your generator, poor exhaust, you get to die from carbon monoxide, fuel mismanagement will set you on fire.... getting a bay door opened up with a grate and some muffler shop assistance....

keep asking questions, you are in the right place!

happy coaching!
buswarrior

[TomC]

If you notice band buses going down the road-they have 5 roof top A/C's for good reason. Mainly for back up if one goes south.
Realistically, if your bus is insulated well, you can get by with 3, even 2 roof tops if they are the older direct discharge type. I have 3 Coleman 13,500btu roof tops with the old direct discharge hang down type vents. My bus has 2.25" of spray insulation and tight RV windows. Up to 100 degrees, I can get by with just running 2. Hotter-kick on the third. All three of my roof top A/C's run directly off my 10kw Diesel generator that hasn't skipped a beat in the 1200 hours I have on it.
You want reliable and everyone the happiest in the bus-just install a Diesel generator and run the roof tops directly off the generator. Forget the inverter, batteries and other crap for right now. Good Luck, TomC

[TheHeavenlyChillbillies]

Ok.  Thanks for the responses guys. 

Here's what I'm thinking...

I'm going to get a battery isolator relay to go between the inverter and the start batteries to be safe. 
http://pages.ebay.com/link/?nav=item.view&id=171709120378&alt=web

The start batteries aren't even 6 months old...I bought 2 new from Napa when we bought her.

I won't mess with house batteries until after we get home.  The bus is cut up in to 5 bedrooms...so the front 1/3rd of the bus can pretty easily be insulated and sectioned off from the back 2/3rds.  The ceiling has already been insulated by the PO and we're making curtains to keep as much sun out as possible.  Hopefully the one account can make the front 1/3rd tolerable.  If not...I'm making little double clamp thing-a-ma-jiggers to hold the windows open a few inches so at least we can get some circulation.

Other than the isolator, inverter, and good 4/0 cable and ens...is there anything else I need?  Should I put a fuse or two between the inverter and start batteries?

[Scott & Heather]

Does he have a gladiator or a Crusader?? I'm confused


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[TheHeavenlyChillbillies]

Gladiator II

[Scott & Heather]

Ok I never heard of a gladiator. I've only hear of a crusader II. That's what we have. Ok I guess I missed something there! Not that it matters when it comes to electrical setup


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[Jim Eh.]

Do you have a bay you could do a temporary mounted rental generator unit? Even a small(er) gas model? May solve a number of your short term goals and you won't have to shell out a major amount of $$$ to start with.

[DoubleEagle]

I am afraid you are trying to do too much with too little. One A/C will not be enough down south, and the inverter setup is probably not adequate. With five compartments to block airflow, someone is going to be very warm. A $100 old generator will not cut it. You better hope the windows still open. Mixing vegetable oil with diesel will lead to problems sooner or later. You better hope the band is not violent.

[TomC]

Forget the inverter, batteries, automatic transfer switches. You want to be cool this summer without much problem? Install at least an 8kw Diesel generator and 2 more roof top A/C's (3 total). Good Luck, TomC