Posted on 11/01/2016 1:14:31 PM PDT by RegulatorCountry
I know there are any number of FReepers who are knowledgable regarding various technical fields, this question arises due to a possible opportunity to buy a "classic" RV for cheap, appears to only need the two roof unit air conditioners replaced, everything else runs well and appears to have been serviced up to very recently. It's a 78 GMC 26 footer, interior mostly original, newer carpet and upholstery, cockpit seats replaced with Honda Odyssey units some time ago in good condition, appliances newer and in good condition.
I've read that the mini-split heat pump can be an excellent update, even though it's to date unusual in the US. The inside blowers are ceiling mount cassettes for this Senville unit that has piqued my interest, three of them, triple zoned. Replacement BTUs are roughly equivalent of the two nonworking units currently in place. The external component of the mini split heat pump will have to go either on the rear bumper or inside one of several ventilated outside access panels, in behind the Dometic fridge looks promising.
Much lower operating cost as well as greatly enhanced compatibility with solar would be why I'm considering going against the grain and installing typical replacements for the existing two roof units. It would take a pretty large solar array to run A/C even with this, but it appears very doable for at least the hottest part of the day, with dehumidifiers and blowers in each of the three ceiling cassettes to help alleviate discomfort if/when the air isn't a good idea.
Battery bank is another issue, but there are numerous Li-Ion, etc. battery packs existing now for this application. They're a bit pricey, but with such an inexpensive RV to install it in/upon, maybe it makes sense?
This is posted to General/Chat, so please don't give me any crap about vanities, I've posted to the correct forum for this sort of inquiry. Hoping the vast knowledge of FReepers as a group can shed light on this particular one, as well as any others that might fit the bill, in addition to the wisdom or lack of it in even considering doing this.
The mini split unit in question is a ductless 3 zone with ceiling cassettes, please see the following: https://senville.com/air-conditioners/
Thanks.
I don’t think it would be a ton unless I tried to stick with lead, probably less than half that. The furnace can go, the unit heats as well as cools. Couple of other things can be done to compensate, smaller propane tank, etc.
My experience with inop RV AC units is minimal but, the 3 times I have worked on them, all they needed was a new motor start up capacitor and lubrication. Does it trip breakers when the AC tries to start?
The thought is off-grid without having to run into town every week or two for propane. Propane would remain for tankless hot water and stove, but I’d be cooking outside as much as possible. Looks like a big coach but cooking kicks off a lot of odors, heat and humidity. It’s a pretty small space all considered, 26’ long by 8’ wide, regardless of external appearance.
I’ve admired those, but short of hanging it on the back of the RV I don’t see where it could go, and that would be a thief magnet, unlike the external component of the heat pump which honestly looks like a narrow cooler with a vented fan on the side
I’ve been looking at the tankless hot water, many have made it work with retrofitting but there appear to be challenges in getting it to work right. Navy showers, cutting it on and off to save water and propane, causes problems with the sensors and you get ice water because it thinks it’s supposed to shut off when you turn off the shower head.
The newer front unit appears to have been damaged with a low clearance issue, no surrounding stress cracks in the roof or anything but I think that one’s shot. The back one looks vintage and has been dead for some time. I don’t believe either is salvagable.
Ductless? Doesn’t that mean free of duct tape repairs? :P
tankless HW - Takagi Jr is the way to go. I have been using one for 8 years - no issues.
Generator, get a variable speed that idles, otherwise the constant hi rpm will drive you nuts.
You still need duct tape in an old RV even without any ducts. The GMC is much better about it than most other 70’s models due to it’s fuselage style construction, but old exterior seals and gaskets spring leaks often enough that a stop-gap measure is necessary until you can get up there and reseal with something a little more permanent or completely replace the gasket.
Thanks for the advice on the Takagi, Jr., I will certainly look into it. Is there anything else that you’ve done to get past the cutoff issue, like a small reserve tank ahead of the unit? Why does this model not have the issue that most of the others appear to have?
Regarding the generator, I’d love a quiet one. That old Onan’s a beast. But, it does work and it works well. Replacement is another big chunk of change. It’s been rebuilt so should be good for a while yet.
Have you considered replacing your units with newer heat pumps? When we ordered our 5th wheel, we specified two 15k heat pumps. Only use propane when the temp drops below 35. And with the efficiency of the new units we spent 6 weeks in Florida last July and only needed to run one a/c unit.
I think you’ll find more problems trying to adapt the split units running off solar than the cost of new heat pump units running your generator.
Hey, you’re lucky the appliances aren’t Avocado Green!
I have 41 years exp in hvac and have installed quite a few mini splits including several with multi indoor units matched with a single outdoor unit.
I believe that the mini split could be adapted for an RV although I have not seen that application before.
The amperage draw for the cooling attained with the “inverter” style mini splits is very low and most act as heat pumps to provide heat in winter. I would recommend a good generator sized for it...I don’t know enough about solar power arrays to advise.
A couple of things...don’t buy a system off the internet. Contact a local HVAC wholesaler and price them. Warranty parts for systems bought on the net are sometimes impossible to acquire.
Don’t buy one of Chinese mfg...use Japanese or Korean.
That’s sound advice and probably much more practical but I like to try to push the envelope if I can find a way to make it work. I also don’t want to be having to run in for propane refills frequently, the tank is pretty large. It’s not as if I could pitch it in the back of the truck and go trade it in at Blue Rhino or anything.
High watt loads like AC, electric stove and washer/dryers will drain down a battery bank fast. Real fast. You can cover the whole roof with solar and it will not keep up with the daily amp demand. In addition, for any of the AC using devices that are running off the inverter, inverters are only about 70% efficient. That means 10 watts worth of energy in gives you 7 amps of energy out.
For running AC and other high electricity users, a generator is needed. Run the AC, electric stove and such off of the AC output of the generator and the DC output to the battery charger. Use a quality charger set up for multiple inputs such as generator, shore power, solar and wind.
Bottom line is for AC and other large draws, a properly sized generator is needed, solar and wind will not be able to meet the demand.
i will second dont use chinese mini splits
crap no spare parts and expensive if you need them and can get them
rennai is good also for tankless water heaters
Thank you, yours is exactly the sort of first hand knowledge and background I was hoping to benefit from. But, YouTube is full of people claiming to be powering their A/C with solar in an RV, for example:
And many others. Are they full of it?
Also, do you have any exposure to Nautikflor synthetic teak marine laminate? It’s beautiful, can be glued down, no problems with thermal expansion or contraction, considering it to replace carpet if I buy this thing. Not cheap, but there’s not that much floor to cover, either.
I know this may sound obvious, but you said you had a well with a panel. Do you have 220 already coming onto the property? Worst case you could add a 30amp circuit to the panel and you could run the coach with it including 1 a/c unit.
If you only have 110, you could get by with a small heater in the coach, but you’d have to run the generator for the a/c.
Since you are going to a static site, what about wind? you might find the technology is more advanced for wind to accomplish what you want to do.
If you want a good resource for your application, try RV.Net. There are people that have probably tried every application to go off the grid and will be willing to help. Good luck.
One last thing...if this is being set up for Hillary amd Bill to go on the lamb, disregard anything I said previously.
Best of luck with your new toy, and if/when you get a chance, please send updates with pics !
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