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AC with internal generator in Sunrader 18'


Raul

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Hi, 

I recently got an 18' Sunrader from 1984 and I'm wondering if it would be possible to build in a rooftop AC that is powered by an internal generator. Does anyone know where the generator could be located on the inside? Are there any alternatives? I'm not sure I want to have a rack on the back bumper with an external generator chained to it. I understood that there is not enough space on the roof to power the AC with solar panels? 

I'm totally new to motorhomes and travelling in a RV. I had initially planned to drive from San Francisco to Chicago, going through the South Arizona, Texas, Louisiana, Tennessee in August. I know it will get insanely hot and humid and I'm wondering even if I would install an AC, would the generator shut off in that heat? And would the AC even be able to cool down the Sunrader? 

Thanks a lot for your advise upfront.

Raul

 

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It won't be possible to power an AC unit off of solar/ battery.  The power simply isn't there.  It isn't necessarily about the solar panels to power the AC, it's the battery bank that would need to be huge.  The solar array would then also have to be quite large to be putting out enough power to keep the batteries charged.  Some have claimed otherwise, but I think it is a claim mostly to get the youtube views. 

The location of a generator comes down to what generator you'll be using, what space inside you want to "give up", and how crafty you are.  If the generator is inside the RV it will need its own separate compartment built to keep exhaust fumes out of the vehicle for obvious reasons.  

A properly functioning/ ventilated generator should not have problems running in heat.  

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Thank you! I think the only 2 places where it could fit is either where the oven (doesn't work and don't really need it, only the stove) is or where the furnace (if the AC would heat too) is. I'm not handy at all, so I would have to look for someone to help me with this in the Bay Area. 

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Welcome to the tribe

Living in CA with all its laws and a lawsuit society, most RV shops will only install RV rated generators = big $$$$

If you don't have a roof AC now then careful shopping will get you a smaller 9200btu  AC that will run on a 2500w portable generator. There may be a lower current draw 11,000btu ac, but it escapes me now.  A normal 13.5K AC will need a 3000 w+ generator. There are several threads here of bumper-mounted generators in baffled quiet boxes.

Go slow and ask lots of questions, it's easy for "local expert" to steer you off the deep end

A side note does your RV have the upgraded 1 ton rear axle

Ah ha 

Colman Mach8 Cub 9200btu 1550w cooling power draw

Dometic Penguin 11,000 BTU  1382w cooling power draw

 

Edited by WME
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Building an internal storage compartment for the generator so that it can run without needing to take it out is a big undertaking. ventilation of the exhaust, gas lines, air flow for cooling, , access to the controls, vibration and noise isolation - all have to be considered carefully.  I know because I've done it and in hind sight I'm not sure if the effort time, storage space and expense was worth it.  But now I've got an incredibly quiet internal generator that I can run and to the people in the camp site next to me the AC unit on the roof is louder than the generator.   Exhaust is vented 14' up with a Gen-turi system.  If you are not planning to do this yourself you could be in for a very, very expensive generator install.  If you can figure out how to mount it on the back bumper or somewhere else outside it will be much easier and cheaper.  A proper internal generator box really takes up a lot of room.  I have a 21' Sunrader and used the old (stupid loud) Onan generator spot plus some real estate I gained by putting in a different water tank.  If you don't have an existing generator bay then you are going to have to give up something big to fit a genny inside.

If you are thinking that you will be able to drive along and run your generator/AC under-way then you have a whole other level of difficulty to overcome because the air flow needed for cooling the generator changes dramatically when driving vs. stationary. 

It is possible to power an AC unit off of a small portable generator, but may not be easy.  To get my AC unit to work reliably I had to use a Micro-Air EasyStart soft starter, which is a spendy piece of kit, but now I have had zero trouble with the 13.5K AC on my Honda eu2000i.   

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RV generators are designed to exhaust heat and exhaust gas out the bottom this way there is little chance of it getting inside the MH.  They draw fuel from the vehicle tank making fueling safe. The only really safe place for any other type of generator is on the ground IMHO. If you want to reliably start an AC unit 2200 watt generator would be the bottom line without adding a hard start system it will run most AC units. All though inverter type generators are quieter by design because of the speed they have to turn but when they are working hard they are pretty noisy.

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Coleman Mach 1 power saver 11,000 btu is the lowest draw roof air on the market last time I looked.  The Polar Cub 9200 btu draws a whopping 13 more LRA than the Mach 1 ps!

Interestingly my old install manual states that my 11,000 btu Dometic Brisk Air, needs a 2500 watt genset.   But I cannot find that info for the ones on the market now.

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Thank you very much everyone! It sounds like if I go down the internal generator path it might get really expensive. Just out of curiosity, do you guys know a company or someone who could do that reliably in the Bay Area? But I think I will either consider an external generator or a different route to Chicago.   

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  • 3 weeks later...

We removed our A/C from our 18 ft sunrader when we had it. Replaced it with variable speed in or out vent fan. We did not have a generator. When parked open windows on the cool side of the rig, set the fan to exhaust and pull cooler air in through the windows. The loss of cargo space for a generator is a huge impact in a 18 footer. If your bent on having a generator installed give these guys in Sacramento a call http://rvdoctorgeorge.com/ see if they are willing. I am sure they could hook you up with a running genset. I doubt that anyone can give you a real price over the phone. The install will be custom with many many man hours involved. It would not be a couple of days project. There are also a couple of RV shops in the Santa Cruz area that do repairs not sure about custom installs. You are also entering the RV season, everyone and his uncle has their RV at a repair shop getting something fixed. Take a number!

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