Air Conditioning on battery?

[rkentb]

Please forgive my lack of knowledge on this topic. I’m trying to read up on Airstreams before possibly getting one. I’m also new to RV’s in general which makes my learning curve even steeper. But i’’m hoping you guys can help me figure something out.

I like the idea of boon-docking as often as possible. I live in FL so one of my primary concerns is cooling off the RV interior. As I understand it, you cannot run an airstream’s ventilation fan or Air Conditioning unless hooked into shore power or using a gas or propane generator. I’m hoping to avoid carrying a generator.

Is it true that you can’t run the Air Conditioning off batteries at all?

Is there a way to get around that with solar panels and better batteries? Could you run the AIr Conditioning or the fan off the batteries for a while if you had an upgraded electrical / solar setup?

[Daquenzer]

Nope. No can do on the battery. Or I should say not practical. If you want to run your AC you will need a portable generator that puts out close to 30 AMPS. Otherwise you would need so many batteries, panels, and a very expensive inverter (4000w inverter). It isn’t practical on an AS. It would be cheaper and less weight just to take a generator.

The subject of generators is on other threads. That can be a bit controversial. I have 2 small Honda Generators that I put in parallel with a separate gas siphon can that will have them running for some time. Others have one larger generator. They come in all shapes, sizes, prices, etc. I personally like the small ones because they are easy to lift. And if I want to just take one I can as a back up power supply.

Others like one big one. Some like gas. Some like LP.

All a matter of personal preference and usage. No right or wrong answer.

And if it is cloudy, raining, or dark you have the issue of not enough power coming from the panels. So generators are really more practical IMHO.

[fran&frank]

Running a ventalation fan off batteries on a stock trailer is not a problem but eventually you will need to recharge the battery-- a generator or some solar panels. Running air condiitoning is a differnet story. You could spend $10,000 or more upgrading to lithium batteries and solar and still only be able to run it for for a few hours. Or you could spend $800-2000 on a generator and be able to run it whenever you have the generator running.

[rkentb]

Is there any good way to carry a generator if I’m going to pull with an enclosed SUV? Can generator be mounted to exterior of trailer somehow?

[rowiebowie]

The short answer is yes if you don't exceed tongue weight. I recall a few posts about it with some nice custom trays or boxes to house a lightweight (or two) generator. Wouldn't know what key words to search for, but someone will come along who knows.

[pteck]

Academically, one could run A/C on batteries, but agreed with others that running it meaningfully for any period of time is not practical. Still ultimately need a way to replenish the batteries.

In regards to having a compact generator kept outside of an SUV capable of running a high performance A/C unit... I believe this might be what you're looking for. And it all works exceedingly well.

http://www.airforums.com/forums/f427...ny-196699.html

[uncle_bob]

Hi

One answer to the generator issue is a propane fired generator. That gets rid of the "gasoline stink" issue. Just how safe you feel with bulk propane here or there .... do some reading and make an informed decision.

Even *with* a generator, running A/C in the hot months can be interesting. One A/C will cool a smaller trailer. For a larger trailer (like a 30') you may need two running. A lot depends on how much shade there is, the temperature out, and the humidity. 100 degree heat / 90% humidity / full sun / no awnings / 30' trailer is in the "need two A/C's" range for most of us.

Running an A/C full time burns fuel. You can go through a lot of propane or gasoline trying to do it for a week. The simple answer is ... you are mobile, go where its not so hot

=======

Fan on battery works out like this:

The fan can easily pull 2 amps when running at a reasonable speed. In 24 hours that's 48 amp hours. In a "single battery" trailer, that's more than you have. With a pair of batteries, you are about at the 2/3 point. Will the fan run fast for 24 hours? Probably not.

The fridge likely pulls an amp so you just used up 24 amp hours with it. Fan running at speed plus fridge is all you have on a two battery setup.

On a reasonable sized trailer, having enough solar to make up those sort of numbers is very doable.

Bob

[Menno]

I saw the replies on running on batteries. I indeed heard it is possible with major upgrades on solar panels and batteries I met an airstreamer who has done it.
I went for the small 2000 watt Honda generator and just installed the easy start on my smallest of the two AC’s (13.5K ) in my 33 ft classic.
Have not tested it yet. Will probably be not enough to cool down the entire rig with just one AC, when is is truly hot and sitting in full sun. Still better than nothing I would think.

[AirMiles]

Originally Posted by uncle_bob

Hi

One answer to the generator issue is a propane fired generator. That gets rid of the "gasoline stink" issue. Just how safe you feel with bulk propane here or there .... do some reading and make an informed decision.

Even *with* a generator, running A/C in the hot months can be interesting. One A/C will cool a smaller trailer. For a larger trailer (like a 30') you may need two running. A lot depends on how much shade there is, the temperature out, and the humidity. 100 degree heat / 90% humidity / full sun / no awnings / 30' trailer is in the "need two A/C's" range for most of us.

Running an A/C full time burns fuel. You can go through a lot of propane or gasoline trying to do it for a week. The simple answer is ... you are mobile, go where its not so hot

=======

Fan on battery works out like this:

The fan can easily pull 2 amps when running at a reasonable speed. In 24 hours that's 48 amp hours. In a "single battery" trailer, that's more than you have. With a pair of batteries, you are about at the 2/3 point. Will the fan run fast for 24 hours? Probably not.

The fridge likely pulls an amp so you just used up 24 amp hours with it. Fan running at speed plus fridge is all you have on a two battery setup.

On a reasonable sized trailer, having enough solar to make up those sort of numbers is very doable.

Bob

This is the answer I would have written if Uncle Bob hadn’t beat me to it.

I dry camp in the Florida heat with a single A/C 25’ Airstream. I have the “triple” awning package which is a must have in high temperatures. I run both fantastic fans day and night from a 230AH battery bank and 400W of solar. I have a Champion DuelFuel generator which is run from the Airstream external propane port for A/C or microwave use when needed A single A/C with dual fantastic fans works well for us to dry camp in our 25’ Airstream. Dual fantastic fans is better than dual A/C when dry camping.

[mkcurtiss]

Originally Posted by rkentb

Is there any good way to carry a generator if I’m going to pull with an enclosed SUV? Can generator be mounted to exterior of trailer somehow?

You have asked a good question.... We pull with a Tahoe.....same situation....the last time I carried the generator, I wrapped it in a a giant contractor trash bag, sealed it off good, and there was virtually no gas smell. You will need gas as well, but you can wait til you get close to your destination and just wing it with the gas can......

[mkcurtiss]

I think the suggestion to "go somewhere where it is not so hot" was great advice.....Go to the hot areas when the weather is cooler. To run a/c you need at least 4000 watt generator, given that you also need to run the converter, and fridge, etc......Really, a 5000 watt generator is ideal, but at that size, they get noisy....its doable, and if you are boondocking all by yourself, who cares how noisy you are......as long as you can sleep. ....but you will need lots of fuel, and even lots of propane if you go that route, but gas is less hassle, i m o.

[mykytiukr]

Plenty of videos on youtube of people running a small AC from solar panels with links to everything they use!!!
On a side note: One marine deep cycle battery with an inverter ran my 110 volt small fridge for three days. Same battery fully charged battery ran an old tube TV/VCR combo for two hours. Never tried the roof AC but I believe I might get about 30 minutes before the voltage would drop enough to cut the inverter. So, to get 12 hours of AC time I would need 24 batteries at about $130 each and at least 60 lbs each. Then the batteries would need to be charged at at least 10 amps EACH overnight. Not really practical when you can use a Honda 2000 generator at maybe 2 or 3 gallons of fuel all day and softstart wired to your AC.

[pteck]

Originally Posted by mykytiukr

Then the batteries would need to be charged at at least 10 amps EACH overnight. Not really practical when you can use a Honda 2000 generator at maybe 2 or 3 gallons of fuel all day and softstart wired to your AC.

You got it. An A/C will use something like 200 Ah per hour from batteries. Not sustainable even for the most exotic banks here costing over $20k installed.

This might be useful for a quick lunch pit stop.

Why bother relying on batteries, when it's more effective and efficient to power the A/C directly with a generator. To your point, who wants to hear a generator run at night.

[uncle_bob]

Hi

If you have the stock fridge that AS puts into most trailers, it will run on propane or 110V as a source of main power. A few of them will use 12V but they are a bit rare. The propane / 110V units have a control board and a few other bits in them that run on 12V. Depending on exactly which bits you have, current drain on 12V may be a bit more or a bit less than 1A. It's still a pretty good starter number.

If indeed you *do* have one of the fridges that runs on 12V as an alternative, that will use more current than the 1A for the control system. There also are compressor based fridges that run on 12V all the time. They also pull a bit more than the 1A "magic number".

With all lead acid batteries, you have two magic numbers. One is the amp hours you *should* use. The other is the amp hours you *could* use. To keep the life of the battery reasonable, most of us stick to the "should use" number. That's about 1/2 the rated capacity of the battery. If you discharge a lead acid battery to it's "empty" level on a regular basis, you likely will be shopping for batteries fairly soon

Bob

[Gsmblue]

Originally Posted by mkcurtiss

You have asked a good question.... We pull with a Tahoe.....same situation....the last time I carried the generator, I wrapped it in a a giant contractor trash bag, sealed it off good, and there was virtually no gas smell. You will need gas as well, but you can wait til you get close to your destination and just wing it with the gas can......

I put our largish Champion 3100W gas generator in the airstream when we tow. It sits between the shower and bathroom over the axels and I have tie downs for it. I put the gas can in the shower and I have the vents open. Never had an issue with the smell of gas building up. Converting to propane is on the list, but not a priority. We really only do about a week a year with the generator.

Hope that helps!