Roof top ac/3startingbatteries/inverter

[Wanda bus]

Hello! I have been researching how to ac the bus while driving. Seems to be an issue with rear mounted mini splits. I have thought about using 3 parallel deep cycle hybrid batteries plus inverter to run a roof top ac placed directly above the driver. This would only be used while driving, therefore the batteries would be charged by the alternator. Hopefully. Does this sound feasible? Too round about or sketchy? If anyone has any input, I would appreciate it. I say 3 bus batteries vs house batteries ( lithium) because I thought that’s what it would take to leave enough power for restarting the bus.

 

[s2mikon]

Tell us more about your bus. Engine ect.

 

[rossvtaylor]

I'm on my phone, or I'd find the link for you...but you should search for and read the "THINK! Before you remove your factory A/C" thread. That may not be the exact title, but it's close...and the fact that I remember it means it made an impression. There is some good discussion about removing the factory stuff...but there's a lot in there about what you propose and how much cooling a rolling bus requires.

 

[Ronnie-SKO]

I can say from experience that a rooftop a/c will cool the drivers area, but not the whole bus while driving. Either put a wall behind the drivers seat or a curtain. I use a generator to power it.


Powering it with batteries off the alternator, not so sure that will work well for any amount of time. You would need to know how long your alternator can put out the amps needed.

 

[john61ct-SKO]

Yes it will take a powerful alternator to keep up with an aircon unit that could maintain a big temp differential on even just a 10' section of bus

unless very well sealed and insulated.

 

[Wanda bus]

Bus is a navistar 3800 T444E. Also, want to reprogram the governor if anyone knows anything about a 95 model. I have read lots and have a diesel mechanic to help. Apparently no computer until the next year.
But anyways, I will ask my mechanic about upgrading the alternator and if it would be advisable for this use. Any other ideas for cooling the driver? My bus never had an air conditioner and I was informed that putting an indash ac while costly could also damage or be too much for the engine since it was never built to run an ac.

 

[Truthseeker4449]

Bus is a navistar 3800 T444E. Also, want to reprogram the governor if anyone knows anything about a 95 model. I have read lots and have a diesel mechanic to help. Apparently no computer until the next year.
But anyways, I will ask my mechanic about upgrading the alternator and if it would be advisable for this use. Any other ideas for cooling the driver? My bus never had an air conditioner and I was informed that putting an indash ac while costly could also damage or be too much for the engine since it was never built to run an ac.

If it does not have an ECM, then you have a mechanical indirect injected T444, not the electronic, direct injected T444E. This is an important distinction as they are completely different engines sharing only a displacement.

Who informed you that your engine was never built to handle AC? The same engine was installed in pickups which certainly had AC systems. I don't believe building an AC system for the driver only would be a significant load at highway speeds for a bus. Adding 2 or 3 compressors to cool the whole bus is a much larger load and can require some interesting fab work to make it happen. The later 7.3s definitely were able to do it and propel a 40 foot bus with only 210HP.

Look for a data sticker on the engine, it'll tell us which engine it is and how much power it has. Truck engines are offered with a variety of power ratings. The differential gear ratio and transmission will dictate your maximum possible speed regardless of governor settings.

 

[s2mikon]

If your bus does not have a computer or electronically controlled engine then you have a mechanically controlled engine. Or otherwise known as a T444. Can you tell us how many rpm this is going at 55 mph? What transmission is in there now. Do you drive it a lot or would you if it had ac and would go faster? Since this is the same basic engine as the ford f250 and f350 used AC brackets would not be to hard to find. This would allow you to install under dash air in the front. If you found a compressor large enough like the one used in the expedition you could install 2 units in there.

 

[Mountain Gnome]

You don't even need to add in-dash air. You could use the factory brackets and compressors on the motor as stated above by s2mikon, and install an overhead unit to go with. May be cheaper, and give you better cooling - more BTUs and better air circulation.


Find a donor bus from a junk yard with the units you need; get new/rebuilt (a) compressor(s).


My Cummins 5.9L has 2 compressors, 2 separate overhead AC systems. I don't even notice any drag on power when they are running, like I do with my other cars/trucks/vans/SUVs.



good idea for you .... ???? .... that's up to your needs.



That motor is plenty strong. Find a new mechanic. He is just not wanting to do that job (in-dash installs suck), and leading you astray.

 

[s2mikon]

Here is what I used for my rear ac. https://www.ebay.com/itm/12V-AC-Air...-Caravan-Truck-Bus-Motorhome-360/274430319822

 

[s2mikon]

Here is what I used for the front. https://www.ebay.com/itm/12V-LCD-Di...For-Bus-Truck-Evaporator-Caravan/203054288495

 

[Doktari]

Thanks for the links. I’m weighing the options for A/C also.