Using Solar Panels

[GummyBear]

I'm building solar heated showers in 2012. I have a panel of black hose for heating. I'm trying to find out if anyone has figured the optimal direction and angle for solar panels on the playa. (same concept applies to solar water heater panel ... get the most sun)

Thanks,
Ken

[motskyroonmatick]

It should not be too difficult to make the holder for the panel adjustable that way you could align it correctly and adjust it a couple times a day if you felt like it. Or if you decided to only take showers in the late afternoon you could set it so that it was receiving full sun just prior to that and would be good to go when you wanted to use it. Stake it down so it does not become a kite. Even heavy things get thrown around by the wind if not secured in some manner.

[teardropper]

I have a PV soar panel I use to charge my battery bank. I used to use this panel more, but now I've just been using it for BM. So I made a fixed mount, and stake it with 18" rebar, for the 40˚ north latitude of BRC and for the month of September. I think it's about 50˚ from vertical and it's pointed due south. It has to do with the sun hitting the collector at a 90˚ angle from the declination of the angle of the sun and horizan. I think. Anyway, I believe this is all, is this a word?, Googleable. As you can see, PV or hot water, you may have to do some cleaning of dust. Also, these numbers would be the same for either.

A pic of this is on page one of this thread...

[Tiahaar]

http://solarelectricityhandbook.com/solar-angle-calculator.html
yes, google is our friend

http://www.flickr.com/photos/23693019@N00/6740920717/

[wimala1]

i used solar this past year. ran my swamp cooler, supplemental fan in the tent, a light in the tent at night, charged the phones for the drive out - it was great!! i used a charge controller and had just a normal car battery from walmart ($50) which i gifted to my neighbor with an rv at the end.

i used the panel from a solar attic vent fan - already had the panel and it produced great power - i didn't lack for anything.

would i have bought a panel? well, i was determined to use solar out there so maybe. but, the "what do you do with it after" thought came in and i just used what i had. i also had the harbor freight solar kit - used the charge controller from that. i didn't even take my inverter. the harbor freight kit is my back up for hurricanes if we loose power. fighting for gas for a noisy generator isn't my idea of fun!! my supplemental fan was one of those that plugs in to a car cigarette lighter - already dc so no problem. the best thing i did by far was to make a monkey hut. that kept so much sun and heat off my tent & was worth all the planning & setting up & hoping that someone would cut my 6ft section of rebar (not a good idea by the way, spend the money on the ones that are precut!!). i used the sunblocker tarp and it was worth all the $ i paid for it.

i did find that you are out and about so much that you are not at your camp long enough to need power much during the day. it was wonderful to sleep in though with that fantastic cool air from the swampie & it was also extremely nice to turn that light on in the night when i did find my bed.

sometimes I think that if we make our camps too comfy, we don't go out and explore!!

i will do solar again this year - and the most fantastic of all inventions - the monkey hut!!

[Father_Burn]

We extensively use solar in our theme camp. I was running 8 80Watt BP pannels, and Outback Charge Controller, 8 Golf Car Batteries from Sams Club, a Samlex AC battery charger and a GoPower 3KW inverter. We also had a generator for backup, and playing after dark. Think of it as a hybrid. The panels were on top of my RV, and yes, I had to clean the dust off of them daily. I used a ladder and a push broom. Our panels were level on the top of the RV. We saw about 480Watts from the 640Watts of Panels at peak. However it performed wonderfuly. We kept the 60 person camp lit up 24X7, ran our grey water evaporation system, and Ran the sound system (1.8KW) from noon till 4-5 off of it. On days where I might want to sleep in, we'd run the AC on the camper off of it too. At 4-5 the inverter would start beeping about low batteries, and we'd fire up the generator. I had a transfer switch that would switch everything over to the Generator automaitcally, and it would charge the batteries untill we turned it off at midnight. We had the same exact system without the solar in 2010, and didn't have nearly as many lights in camp (10 strings of LED christmas lights instead of 70) and no real stage lighting. We went through close to two tanks of fuel a day in 2010 compared to less than one per day in 2011 with the solar using the same 7KW Honda Generator.

A few things:
Get a MPPT charge controller. The outback might be overkill, but a MPPT controller greatly increases the efficiency of your panels.
Ban all lights that aren't LED or Cold Cathode Flourescent. If you use less electricity, what you produce will go farther
Get Golf Cart Batteris. It's the best battery for the money. Make certain you use them some before you go to break them in.
Use Thick copper wire for everything. Exceed the manufacturer's of the equipment's recommendations. Bigger really is better here, because it reduces your power losses.
Make everything automatic so you don't have to mess with it during the burn. You're there to do other things.
Avoid modified sine wave inverters. Alltough they are slightly more efficient, the square wave they produce instead of a sine wave will make many things very unhappy.
Run higher than 12V on your batteries if you can. It improves efficiency, and reduces the size of wire you'll need.

Have fun! If you have questions, email me netwizard<at>gmail<d0t>com

[teardropper]

Get Golf Cart Batteries. It's the best battery for the money.

While I agree, I also use AGM's, the best sealed battery. If size and weight are no issue, where you want the most a/h for the least $$, golf carts are the best. My two 225 a/h 6 volt (two wired to 12 volts) golf carts cost $70 each. My 75 a/h AGM cost about $160. But I have that under the hood of the motorhome to run the in-dash Alpine stereo. Runs for 8 or 9 days and then starts the rig just fine. Again, that's the Optima Blue Top. I take five deep cycle batteries, one just as a back up, and except for the Optima, they are all flooded lead acid. I just make sure to have everything fully charged when I get to the playa.

I am also a regular camper, mostly camping in my teardrop. So I use my batteries for more than BM.

[7chix&me]

i used solar this past year. ran my swamp cooler, supplemental fan in the tent, a light in the tent at night, charged the phones for the drive out - it was great!! i used a charge controller and had just a normal car battery from walmart ($50) which i gifted to my neighbor with an rv at the end.

i used the panel from a solar attic vent fan - already had the panel and it produced great power - i didn't lack for anything.

How many Watts is your fan panel? Trying to guage how much I need for my camp--just me and my honey. Minimal power requirements like you.
Thanks.

[FIGJAM]

Try this.

http://www.northerntool.com/shop/tools/product_200422029_200422029

[Fufa]

Anyone have an idea how big of a set up is needed to charge up a couple quad batteries (used to light bikes), a deep cycle to light the camp with xmas lights at night, and small things like camera batteries? We currently use a generator, but I hate the noise.

Also, what are some good brands?

[some seeing eye]

I think my earlier post summarizes the calculations.

LED Christmas lights are ~5W per string, running 10 hours 1/2 derating = 35Ah 12 V battery, small
LED bike light batteries are about 7Wh max (4xAA)
A camera battery is maybe 5Wh

So 4 strings, 4 bike battery packs (16AA), 2 camera batteries, 250W a day, 100W~12V panel 10A charge controller, a small inverter to run your 110V LED strings and the bike & camera battery chargers.

It's hard to find a small system with electronics sealed from dust, so as always suggest consulting with the AEZ ae-zone.org. Outback is a great brand, Xantrex is good as well.

Attic fan panels are 20-40W.

[teardropper]

A suggestion... while an inverter can be useful, I switched all my LED lights, which is all I use, from 120 VAC to 12 VDC. I have a 150 watt inverter for small electronics. And I do have a larger inverter just in case, but it is more electrically efficient to use 12 volt accessories instead of inverting that 12 volts DC to 120 volts AC. It's also one less thing that can fail. And has. And you can get just about anything in 12 volt.

[BeachBum]

Anyone have an idea how big of a set up is needed to charge up a couple quad batteries (used to light bikes), a deep cycle to light the camp with xmas lights at night, and small things like camera batteries? We currently use a generator, but I hate the noise.

Fufa, it's really easy to do. Semi-echoing Some Seeing Eye's response:

Volts x Amps = Watts (Watts are a measurement of power)
1 Watt x 1 Hour = 1 Watt-Hour

A standard deep cell is about 80 Amp-Hours at 12V, which means it has slightly less than 1,000 Watt-Hours of capacity. Only use half of it, about 500 Watt-Hours before recharging.

Watts used per day:
- 5 Watts per LED Christmas string x number of strings x hours used per night. Say 4 strings of 5W LED lights x 7 hours per night, so 4x5x7 = 140W per night
- Don't worry about the Watts used by recharge of the bike and camera batteries, it's negligible.

A 15 Watt solar panel will be enough to keep the battery charged for the week. (15Watt x 8 hours of good sun per day = 120 Watts per day)
You'll need one 15 Watt solar panel (about $80), a small charge controller (usually sold bundled with the solar panel, about $25 separately), a 150 Watt inverter (about $15) to take the 12 Volts from the battery into 115Vac. Other people have given recommendations on where to get the parts.

Tricks:
- I bought a new battery for my car last year prior to BM. I used the old battery, and a 150 Watt "cigarette lighter" inverter to run 2 strings of LED lights about 5 hours a night all week without the battery
needing to be recharged. Need to get a "battery clamps to cigarette lighter socket" for like $5 at Fry's. If it needs recharged once during the week, just ask around if someone will recharge it for you.
- Buy two of the 150 Watt inverters. These pop like popcorn in the desert, you need a spare.
- Protect the inverters and charge controller from playa dust in a bread box sized plastic storage container. Cut a small hole in the plastic to get cords in and out. Then cover the hole with duct tape.
- Turn off the strings religiously when you go to bed, otherwise it can drain the battery. Maybe turn off 3 of the 4 strings at midnight or so.
- Idiot camp mates are going to try to talk you into adding other lights, maybe even non-LED lights (NO!), plugging in laptops, ... You need to tell them to go to hell, otherwise this setup won't work. Sorry.
- Start recharging the battery at sun-up on day one. Keep it on all day. Read the charge controller manual, chances are the solar panel/charge controller never needs to be disconnected from the
battery, even at night.
- Keep idiot camp mates from screwing with the setup, thinking that they are "helping". Enjoy getting nasty with them if they try to screw with it
- If you sometimes need more Watts, like if the idiot camp mate really wants to use this to run a small home stereo also (takes up to 200 Watts), buy a 400 Watt inverter for like $40, instead of
the 150 Watt inverter. For about $200, some Costco's sell a 3 panel 45 Watt solar panels setup with a charge controller in the summer. You can now do the math on this.

Have fun, it's really easy to do

Beach Bum

[Marscrumbs]

As hose is cylindrical it doesn't matter which angle you set it at. That what Solyndra did with their solar modules. just leave a little space between hoses so they don't shade themselves.

[Fufa]

Thanks guys! I'll talk it over with my other half to see if the investment is worth the cost to use this year. He's handy, he'll be able to figure out the rest.

[some seeing eye]

I've suggested in the past that people can get batteries charged at Snow Koan Solar which usually sits between Nectar Village and the AEZ. So a stepwise entry into solar could involve an inverter, a deep cycle battery, your small dedicated chargers and your LED lights. (And a wagon to haul the battery for recharging) The AEZ suggests that people will break their first solar equipment until they merge an intuitive and theoretical model for how they work. So you could start without the panel and charge controller, learn at AEZ and add the other parts in the future. Panel prices generally are falling, but there is a trade war going on, so a difference in price could open between US and Canada prices and prices could go up.

Might be worth buying the battery in Reno, especially if you could convince the store to charge it first.

No guarantees AEZ or Snow Koan will be here this year.

[BeachBum]

I wanted to re-post the calculations for how to use solar power for LED Christmas lights, making the calculations a touch more obvious for people. The calculations are also useful for powering other electronics:

Example - 4 LED Christmas light strings of 5W each (about 70 LED lights each), kept on for 7 hours a night.

Volts x Amps = Watts (Watts (W) are a measurement of power)
1 Watt x 1 Hour = 1 Watt-Hour

A standard deep cell is about 80 Amp-Hours at 12V. So, the battery has 80 Amp-Hours x 12V = 960 Watt Watt-Hours of capacity. Can only use half of it, taking it down to about 400 or 500 Watt-Hours.

Watts used per day:
- 5 Watts per LED Christmas string x number of strings x hours used per night. Say 4 strings of 5W LED lights x 7 hours per night, so 4x5x7 = 140W per night

Watts generated per day:
A 15 Watt solar panel will be enough to keep the battery charged for the week.
15Watt x 8 hours of good sun per day = 120 Watts generated per day

So, the Watt-Hours contained in the battery would be reduced from 960 Watt-Hours by 20 Watt-Hours per day. (960Wh -(140Wh - 120 Wh) = 940 Wh, ...)

Parts needed:
1) One 15 Watt solar panel (about $80)
2) A small charge controller (about $25, but usually bundled with the solar panel)
3) Battery - Deep Cell preferred, an old car battery will also work. (about $80)
4) Inverter(s) to take the 12Vdc (battery voltage) to 115Vac (house voltage). Buy two, they fail easy. 150 Watt inverters are $14 to $30. 400 Watt inverters are about $35.

Connections:
solar panel -> charge controller -> 12V battery -> inverter -> LED Christmas lights

It's easy. Have fun!

[BeachBum]

Whoops, things become obvious to you at 8:00 the next morning that you didn't see at 11:30 the previous night. In the previous post, i should have called a few things "Watt-hours" instead of "Watts". Also, some seeing eye kindly responded (thanks!) that my estimate of how many Watt-hours a solar panel would produce in a day were a bit on the high side. So, since i can't edit the previous post anymore, a correction, with some more info added, here:
---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
USING SOLAR PANELS FOR CAMP LED CHRISTMAS LIGHTS:

Example - 4 LED Christmas light strings of 5 Watts each (about 70 LED lights each), kept on for 7 hours a night.

Volts x Amps = Watts (Watts (W) are a measurement of power)
1 Watt x 1 hour = 1 Watt-hour (Wh)

A standard size 24 deep cell is about 80 Amp-hours at 12V. So, the battery has 80 Amp-hours x 12V = 960 Watt Watt-hours of capacity. Can only use half of it, taking it down to about 400 or 500 Watt-hours.

Watt-hours used per day:
- 5 Watts per LED Christmas string x number of strings x hours used per night. Say 4 strings of 5W LED lights x 7 hours per night, so 4x5x7 = 140 Watt-hours used per night

Watt-hours generated per day:
A 15 Watt solar panel will be enough to keep the battery charged for the week. It only produces about 12 Watts for about 8 hours a day though.
12 Watts x 8 hours of good sun per day ~= 100 Watt-hours generated per day

So, the Watt-hours contained in the battery would be reduced from 960 Watt-hours by 40 Watt-hours per day. (960Wh -(140Wh - 100 Wh) = 920 Wh, ...)
Later in the week, if the battery goes down a bit, the inverter may automatically shut off the lights after like 6 hours each day. Or, just use fewer LED strings.

Parts needed:
1) One 15 Watt solar panel (about $80)
2) A small charge controller (about $25, but usually bundled with the solar panel)
3) Battery - Deep Cell preferred, an old car battery will also work. (about $80)
4) Inverter(s) to take the 12Vdc (battery voltage) to 115Vac (house voltage). Buy two, they fail easy. 150 Watt inverters are $14 to $30. 400 Watt inverters are about $35.
Just go to like amazon, or other e-stores, and search for "15 Watt solar panel" and the panels and other items listed here will pop up.

Connections:
solar panel -> charge controller -> 12V battery -> inverter -> LED Christmas lights

Stereo systems:
Home stereo systems for camp can also be powered like this, using a 400W inverter. Or, better, get a $100 or so car stereo amp so it can run directly from 12Vdc, these can power home speakers easily. Would probably need a $200 45 Watt solar panel, or just get the battery recharged a couple times during the week. If doing solar for anything, use a charge controller, and leave the solar panel -> charge controller connected to the battery at all times, otherwise this setup is useless.

It's easy. Have fun!

[some seeing eye]

I appreciate Mr BeachBurn providing a useful answer! The more people who learn solar, the better!

[oscillator]

Here is a 85W solar system I put together a coupla years ago - works great to charge 24aH MV lighting batteries, run a small sound system, and provide LED lighting in camp.

For me, the big take-away from learning solar, is to match your photovoltaic array with your battery bank. With an eye to expanding this system, I purchased a charge controller capable of 2X of this system, so this year I plan to add another 85W PV panel and 2X battery bank. As much as I like the Optima batteries, I will go with series 6V next time.

The ingredients of this system are not the cheapest, but more robust, efficient and smaller footprint than say, the 45W Harbor Freight option and cheap car inverters that do not hold up in the desert. I think the current parts cost for this system is around US$900 and its longevity makes the extra cost worth it.

As I recall, 2009 prices were:
Kyocera 85w - $400 (now ~$300)
SureSine 300w - $300
Charge Controller 15A - $120
Optima 55aH - $160

Also, big shout to Snow Koan solar - those guys got me hooked!

HTHs,

-oSc-

[BBadger]

The ingredients of this system are not the cheapest, but more robust, efficient and smaller footprint than say, the 45W Harbor Freight option and cheap car inverters that do not hold up in the desert. I think the current parts cost for this system is around US$900 and its longevity makes the extra cost worth it.

Or rather, it's what makes solar power worth using at all. If you're not going to use solar for the long term with relatively constant usage, don't buy it in the first place. It is always cheaper to just pay up front for more batteries or gas and get more out of them if you're not going to use your solar for long durations or in extremely remote conditions (ironically, Burning Man does not qualify as you can easily bring in enough power resources).

For example, for the cost of the 85W solar panel itself, at the "now" prices, you could buy 3x 6V@220AH batteries at Costco. In terms of raw Watt-Hours, you're looking at 3960WH of power. To get that back from your 85W solar panel, at 100% efficiency you're looking at 46 hours of charge time, which is about 4 days of daylight--and not using any power in between. This of course doesn't factor in that you don't want to fully discharge batteries or other things, but does illustrate that it can be much cheaper to go the non-renewable route if all you're looking at is a week trip to Burning Man or something like that.

Go for consumable power sources if you're not in the business for the long haul. Solar is okay for the long haul, so invest accordingly.

[solar guy]

Let's talk apples to apples, kWh to kWh. The average usage for a typical home is approximately 920kWh per month, totaling about $95 per month in charges @ 10.5 cents/kWh. That's approximately $1100 per year spent on electricity, for ~1200W of power used 24/7 for a year. Using this calculator, for solar power setup that would provide 100% power offset, for a typical 7.5hrs of average sunlight per day in the US, you need a 5.38kW solar array. Going rates for solar cells can vary depending on array size; I used $6/W as the average cost for an array like this. An array that size would cost roughly $32,000 to install.

BBadger, the cost for solar is much lower these days, about $3 per watt to have it installed and closer to $1.50 per watt to do-it-yourself. You can find 5kW solar kits for about $12,000 online. Still a big ticket, so think about starting small, 1kW for under $3,000, and adding on later.

If you need something portable for the Playa, check out joos or solio solar chargers for phones, tablets, laptops, cameras... anywhere from $35 to $150.

[edit: link removed- Eric, Mod]

[garyt]

I love how eplaya has all the best information, reviews, etc just when I need it. So base on figjam's swamp cooler, I've decided to go solar this year for BM and I have some questions which I hope some of you could help with. What I have is a

1. 45w solar panel kit (with charge controller) from Harbor Freight
2. 80 Amp Hour deep cycle battery from Sears

What I will be powering is
1. FIGJAM's swamp cooler (92gph water pump & 48watts pc fan)
2. Color Changing RGB Led Strip
3. 12v @15w bulb x 2
4. iPhone charging
5. Small non-amplified PC speakers (maybe)

My questions are
1. Is my solar panel - battery setup enough for what I need?
2. Should I convert my 120vac water pump to a 12vdc or just get an AC inverter?
3. Base on my setup, how much more shit can I plug in or am I maxed out?
4. I read that the deep cycle batteries need to be maintain. Coming back from BM, do I just leave my batteries charged with the solar panel in my backyard to preserve it? What do I do?

THANKS!
Gary

[FIGJAM]

I designed the coolers to be all 12 vdc, so you don't need an inverter for the cooler.

As designed, it uses just shy of 1.5 amps.

I don't know about the other questions.

[some seeing eye]

Figjam, 18W is very impressive!

[BeachBum]

Gary: Cool!
Some info on your stuff:

1. 45w solar panel kit (with charge controller) from Harbor Freight - Gives about 250 Watt-hours of power per day at Reno's latitude in September. Must be connected at all times to do even this!
2. 80 Amp Hour deep cycle battery from Sears - Capacity of 1,000 Watt-hours (12.4V * 80Amp-hours) Can use about 600 Watt-hours of this 1,000 Watt-hours, which will take it down to about 11.0 Volts. Normal battery stuff. The solar panel & battery combo are matched well, won't provide a tremendous amount of power each day though.

What I will be powering is
1. FIGJAM's swamp cooler (92gph water pump & 48watts pc fan) - say 48 +5 Watts times like 6 hours per day? That's about 310 Watt-hours per day right there.
2. Color Changing RGB Led Strip - Only like 5 Watts times about 7 hours per day = 35 Watt-hours per day.
3. 12v @15w bulb x 2 - 30 Watts times about 6 hours per day = 180 Watt-hours per day.
4. iPhone charging - Basically zero Watts.
5. Small non-amplified PC speakers (maybe) - Maybe 3 Watts times 10 hours per day? Perhaps about 30 Watt-hours per day?

My questions are
1. Is my solar panel - battery setup enough for what I need?
2. Should I convert my 120vac water pump to a 12vdc or just get an AC inverter? - (I think there's a 12Vdc to 120Vac inverter in the Harbor Freight solar panel kit)
3. Base on my setup, how much more shit can I plug in or am I maxed out?
4. I read that the deep cycle batteries need to be maintain. Coming back from BM, do I just leave my batteries charged with the solar panel in my backyard to preserve it? What do I do?

So, looks like you'll generate 250 Watt-hours of power per day, and use about 310+35+180+30=555 Watt-hours per day. Probably need to cut back on some power used.

Best way to cut back on power used is to cut down the Watt-hours used by the swamp cooler. Like to Figjam's 18 Watts ( 12V * 1.5Amps), and limit the hours it's used each day. Also, maybe change the lights to LEDs or LED Christmas light strings (5Watts each). Another thought is to provide a bit more for lights and sound (the fun stuff), and really cut back on the swamp cooler, you probably won't be in your tent from mid-morning till evening anyways. Or, can add a little bit of power by getting the 55 Watt Coleman Solar Panel kit from Costco for $200. They also carry a much, much smaller 60 Watt folder semiconductor solar panel for $270 at the bigger stores. You have the basic math to figure out if it'll work.

If your battery goes down too far, you can always jump the battery by your car, idling your engine for like half an hour or an hour. Or, ask someone with a generator to top it off. After TTITD, just give the battery a full recharge, sit it on a shelf, and it should be good till the next year, checking it with a voltmeter every few months to make sure it didn't discharge itself.

Nice and fun project! Have a good time with it!

[wkorthof]

Willpower here from Sno-Koan Solar... we will be back again this year with lots of solar power. We're planning our biggest array ever (~30kW) for our neighborhood, Nectar Village. Again we'll be offering our open-access community charging station. We're also putting up a second large array (~24 kW) for the CORE art project power grid surrounding the man-base. We welcome everyone to come visit, plug in, and recharge just about anything with batteries on the Playa. In addition, we expect to work with probably a dozen or so other camps, art projects, and individuals to bring more solar power. Doing our part to make solar work, help eliminate dozens of generators, and save thousands of gallons of fuel.

Yes, solar panels can be had for roughly down to $1 per watt wholesale. Hint----shop online, big box retail stores are not a good deal for solar panels. While it won't work for everyone, switching from generator to solar power can be cost-effective even on the Playa. Suppose you were planning a generator for your small camp or project, say the Honda EU3000. Purchase cost of about $2000. Suppose instead bought and brought 2 x 250 watt solar panels + 1 MPPT 12 volt output charge controller (online), 4 deep cycle marine batteries (Costco), and a 12 volt, 3000 watt inverter. Cost would also be about $2000, and you could also run a pretty extensive amount of the normal camp stuff---lights, sound system, blender, battery chargers. At $1 per watt, the solar panels actually scale up at a pretty reasonable cost.

As for dust on the Playa---you want to remember that dust gets into everything, and rain/water can also sneak into any exposed electronics. Generators are very sensitive to dust---they always needs air for both combustion and cooling, and playa dust wrecks havoc. With solar power, you can actually be much better protected against dust. Even when our large solar arrays were covered in dust after a white-out, we they still found them producing a good fraction of full power. Simply wipe off the panels once a day on the Playa, and they work great. We have found that using a push broom on smaller arrays, and/or an electric leaf blower (yes, really) on our larger arrays works great.

[garyt]

So, looks like you'll generate 250 Watt-hours of power per day, and use about 310+35+180+30=555 Watt-hours per day. Probably need to cut back on some power used.

Best way to cut back on power used is to cut down the Watt-hours used by the swamp cooler. Like to Figjam's 18 Watts ( 12V * 1.5Amps), and limit the hours it's used each day. Also, maybe change the lights to LEDs or LED Christmas light strings (5Watts each). Another thought is to provide a bit more for lights and sound (the fun stuff), and really cut back on the swamp cooler, you probably won't be in your tent from mid-morning till evening anyways. Or, can add a little bit of power by getting the 55 Watt Coleman Solar Panel kit from Costco for $200. They also carry a much, much smaller 60 Watt folder semiconductor solar panel for $270 at the bigger stores. You have the basic math to figure out if it'll work.

If your battery goes down too far, you can always jump the battery by your car, idling your engine for like half an hour or an hour. Or, ask someone with a generator to top it off. After TTITD, just give the battery a full recharge, sit it on a shelf, and it should be good till the next year, checking it with a voltmeter every few months to make sure it didn't discharge itself.

Nice and fun project! Have a good time with it!

Thanks for the detailed reply Beach!

I have done a little more adjustments and also have two additional 105AH deep cycle batteries at my disposal. I figured I will have to change my water pump to a 12v like Figjam's but need to keep the same fan just because I have quite a bit of space to cool. I figured I will add a timer of sorts to turn on the swamp cooler around 6am before my structure gets warm so it doesn't have to cool as much and I really only need to run no more than 4 hours of it. Definitely not going to do speakers and get a battery radio instead. Changed all my lightings to LEDs. I don't have the funds to get more panels this year but definitely next year if this works out great for me.

I was going to volunteer for DPW this year but due to work might not be able to get an additional 2 weeks off (bummed). So, I think this year, I'd like to walk around and check out everyone's DIY projects from swamp coolers to solar to shade structures.

[winger]

be prepared to spend 1k and more to power up anything more than fans.

[maladroit]

Just bought a new 30W solar panel for $57 + tax, free shipping!

http://cgi.ebay.com/ws/eBayISAPI.dll?Vi ... 0864773801

They have more available.

Should be plenty for some basic tent power, keep a battery topped off and run some lights and occasionally other small stuff. Hope it's as good as the specs say.

Wow, I just got a shipping notifcation!

Planning to use it with one of the charge controllers here: http://www.allelectronics.com/make-a-st ... ics/1.html