Solar neophyte question

[happydragon]

Ok- standing by for flames, but I am renting an RV for my first BM this year. I don't want to deal with a generator, I am hoping to get some solar panels and lash to the roof to keep the battery charged, run the fridge (I hear popsicles and ice cream are a wonderful idea) and other necessities all week. I have been crawling all over the net, but am still confused. Seems like the most common setup is to use panels and an inverter to charge a deep cycle marine battery. But do I need the inverter and battery or can I just get panels and an charge controller and hook them into the RV battery directly then run everything off that? I assume I there is some type of external unbilical port on most RVs so you can power them externally. On a related note, any estimates of what capacity panels I would need to run the setup? Assume large RV with fridge and AC running (if wife comes AC will be running)

[ygmir]

if the fridge is propane capable, use that........no electric draw and, they work good that way.

[much2naughty2]

aerialmonster, that's not an easy question to answer because there are a lot of variables and it mostly depends on the amount of power and length of use for devices that draw off the battery. Plus other variables like the size of panel and the hours of sun exposure angle, etc etc.......

Shortcutting detail though, it is possible and practical to connect a panel directly to the battery. The risk you run is if you boil the battery with overcharge, which generates gas, that can be ignited and go BOOM. In and open air environment, that risk is very, very low. To avoid that if you are worried, you can install a low/high voltage disconnect. I did a quick search on google and found this site. http://www.12volt.com.au. There are 100's of different models, but try to match the amp and volt output of the panel.

My best advice is don't drive yourself crazy or broke trying to figure this out yourself. search for"Solar Kit for RVs and Campers" and you should get good results for portable solar packages that will work great.

[Captain Goddammit]

The fridge in an RV runs on propane. The A/C draws way more power that you will get from some solar cells strapped to the roof.

You press a button, the generator fires up, does exactly what it's supposed to do. What "dealing with a generator" are you trying to avoid?

RVs do have an "umbilical cord" to power everything externally, from a 30 or 50-amp 120VAC source. Your solar cells will provide low-voltage DC. You can hook to your RV's house batteries, but what you will need is a charge controller to regulate the solar power so you don't fry your batteries.

An "inverter" is a device that converts 12-volt DC into 120-volt AC (at least, that's what most people are referring to when they say "inverter" in the RV world). You connect the inverter to your 12-volt battery to use it to operate 120-volt AC "house current" type devices.

If it's just for Burning Man, you're gonna spend a lot more money, and get a hell of a lot less with the solar panels.

[Captain Goddammit]

any estimates of what capacity panels I would need to run the setup? Assume large RV with fridge and AC running (if wife comes AC will be running)

search for"Solar Kit for RVs and Campers" and you should get good results for portable solar packages that will work great.

I don't think so! You're gonna need thousands of watts for A/C. And since you said "assume a large RV" we can also assume at least two roof A/C units. Three or four thousand watts...

[Token]

Your rental RV will have a generator installed in it. They are usually automatic push-button electric start units that require near-zero effort to operate.

Top off your gas in Empire or Gerlach and bring an extra couple 5 gallon cans of gas to use for refill just before you leave BM.

Have the rental place show you how to use the generator and be sure to find out what extra $ they charge for the hours used. Make sure they show you the "high altitude" switch if it is not automatic.

Be mindfull of your neighbors with the noise and exhaust stink from the generator. Be ready to move or adjust your position in your camping spot.

[LeChatNoir]

Hi aerialmonster,

We have a 15 watt/ 12volt DC solar panel that assists our camp battery for LED lighting. That’s +/- 1.5 watts of AC power. It cost approximately $80.

That’s $53.33 per watt AC/$5.33 per watt DC.

If an air conditioner unit pulls, say… 2000 watts AC, you’d need 1333 of these panels to get this.

That’s $10,666 worth of 15 watt panels. Grated, you could get the cost lower by getting larger panels and lower your per watt cost, but I still think it’d be around $3.00 per watt DC.

Use the genny in the RV and shut it off when you don’t need it. We use solar for our lighting because it’s fun to see if we can do it. But this year I’m charging the deep cycle batteries with an alternator on our Mutant Vehicle.

Be mindfull of your neighbors with the noise and exhaust stink from the generator. Be ready to move or adjust your position in your camping spot.

Yes, please do this. We had someone squeeze in one year and run their generator constantly with the exhaust right, I mean RIGHT by our tent/sleeping area.

[much2naughty2]

ygmir dealt with the frig issue (use Gas) and I read right over the AC. Capt, thanks for pointing that out. I was thinking radio, laptop, lights, ie charging the RV battery.

Tell your wife to just get naked, get a spritzer bottle, and a battery operated fan. Better yet, get a small solar panel that can run the fan, that blows air on the water drops, that is sprayed on the nekked flesh....

[gyre]

About the only time you don't want to charge batteries is to run fans for heat, for exhausting a car for example.

A fridge can be electric in an rv if it is intended for grid use primarily.
The solar systems use brands like sunfrost for low consumption.
There are others from norcold, dometic and the australian versions.
I have a good japanese type that draws tiny power.
the electrics are good for portability vs propane.
Propane is better for off the grid use, unless you have a massive solar setup.

First step is to minimize consumption- fluorescent lights, hid, etc and efficient appliances.
The most generally run off solar is a microwave.



http://www.sunfrost.com/

[Captain Goddammit]

Dude did you read the question? They're gonna rent an RV. It's gonna have a propane fridge. They aren't gonna modify it with any appliances it hasn't already got built in.

[gyre]

Yeah, I missed that.
It never even occurred to me that anyone would try to strap $20,000 worth of panels to a rented RV.

[gyre]

Dude did you read the question? They're gonna rent an RV. It's gonna have a propane fridge. They aren't gonna modify it with any appliances it hasn't already got built in.

FYI There are very portable electric and propane freezers and fridges.
My japanese cooler is the size of 36 quart cooler or smaller.
Can be used built in or carried.
And yes, 12 volt compressor.

[Captain Goddammit]

Like, I know. Has zilch to do with the issue at hand.

[happydragon]

Well, guess my evil plans won't work. I was hoping it could be done reasonably because I wanted to avoid the whole noise/exhaust issue entirely and test the solar waters before I convert my house to solar. Thanks for all the feedback.

[klondike_bar]

another big remnder: youre at Burning Man, in the DESERT. fcuk air conditioning. get out of the RV and go find a hammock camp to lounge at in thier shade/breeze.

by the time night rolls around and youre to drunk/tired to party, it wil be nice and cool in the RV again.

[SnowBlind]

We have a 15 watt/ 12volt DC solar panel that assists our camp battery for LED lighting. That’s +/- 1.5 watts of AC power.

Watts don't change if you convert it to another voltage. Amps change. So if it had been 15 Amps, then yes, that would be 1.5 Amps (assuming by AC you mean 120 Volts).

But 15 Watts at 12 V are 15 Watts at 120 V, ideally. In reality your inverter is going to have losses, but I highly doubt they are 90%.

[Elliot]

Aerialmonster, based on your original post I say leave the wife at home.

Burning Man is not an Air Conditioned type of event. Burning Man is a decidedly Roughing It type of event.

One of the first things I tell people about Burning Man is that it is NOT FOR EVERYONE.

Now.... "Leave the wife at home" is not a nice thing to say. It's not a good way to run a marriage. It should be her decision.

Some couples are inseparable and some do better by keeping their individual hobbies. I'm no freakin' marriage counselor. I'm just trying to save your wife from sitting in an air conditioned RV watching TV for a week, cuz that's just wrong.

[Yiekes, where did that come from? Oh... It's Saturday. I just wrote tomorrow's Sermon. OK. Sermon over. (Puts fire and brimstone back in the drawer until tomorrow.)]