Solar for drop zones

[billvon 2,434]

Many years ago, when we first moved to Otay, we faced the prospect of paying on the order of $50K to get a power line out to the remote area or doing without power. I didn't like either option so I installed a little solar power system to run a few cash registers, lights, the aircraft radios etc. in our one trailer.

Well, then the rigger wanted power. And then we bought some new buildings. And then Buzz wanted air conditioning. And a soda machine. And the military moved in and got industrial-sized coffee machines.

The original inverter was 1000 watts, with 250 watts of solar charging a small bank of batteries with a Home Depot special generator as a backup. Today I just finished installing the latest bank of solar. As of today we are up to 5500 watts of inverter power, 20 kilowatt propane generator, 700 watts of solar, and 40 kilowatt-hours of battery storage. And we use almost all of the available power.

Typically the generator runs for 5-6 hours during the day when the DZ is open. When the DZ is closed, solar alone runs the phones, the refrigerators that never get shut off and the 'night lights.' The inverter's not beefy enough to run the massive old air conditioners in the trailer, so the generator has to be manually started in the summer when they are needed. Ordinarily, though, the inverter starts the generator when the batteries get low and shut it off when they are topped off. It's worked pretty well over the years with only minor problems (mainly blown breakers when the military guys plug in yet another coffeepot.) I think one of the reasons it works so well is that it's autonomous - you can leave it alone and it will start the generator when it needs to, taper off the charge when the batteries are almost full etc.

Some pictures attached.

[dixieskydiver 0]

Solar power kicks ass. Have you taken the time to figure out how much the whole shebang has cost you with gas for the generator and all vs. approximately how much it would have cost you to run the line & pay for power all those years? Do you think you'll end up coming out on top or have you already?

Dixie
HISPA #56 Facil Rodriguez
"Scientific research has shown that 60% of the time, it works every time."

[TheAnvil 0]

What sort of cells are you using?

Ever think about a stirling power generation system?

Stirling engines rock.

Vinny

Vinny the Anvil
Post Traumatic Didn't Make The Lakers Syndrome is REAL
JACKASS POWER!!!!!!

[billvon 2,434]

>Have you taken the time to figure out how much the whole shebang
> has cost you with gas for the generator and all . . .

Heck no. There was a period of time where Buzz was buying the cheapest gas generators he could on Ebay and blowing them up at the rate of one a month. There was a little "generator graveyard" next to the trailers before he finally spent the money on a reliable one. (That one's been running for about 18 months now.)

But my best guess would be around $15-20K for the system we have now, disregarding that little graveyard.

>Do you think you'll end up coming out on top or have you already?

I think we are already way ahead, and we spend about the same amount on propane as we would have spent on power so we'll stay ahead. As we add more solar we'll get farther and farther ahead.

[billvon 2,434]

>What sort of cells are you using?

Some amorphous because we figured skydivers would be landing on them. Well, that's never happened, so the newer ones are glass polycrystalline.

>Ever think about a stirling power generation system?

Nope. None are commercially available, and even if one were, the concentrator would have to be steered with servomotors to track the sun. And with all the reliability issues we've had, the fewer motors the better.

[harryskydives 0]

Hey Bill: I was reading about this Boy Scout that built a nuculear reactor in his Moms garden shed. He did this from stuff that could be found in dumps, antique stores and wal mart. That was not you was it?

Don't run out of altitude and experience at the same time...

[TheAnvil 0]

These guys are pretty cool:

http://stirlingtech.com/applications/offgrid_residential.shtml

Can't speak about their residential units, but their space unit has got well in excess of 70K hours maintenance free!

Are those solar cells single junction? Dual? Triple?

Vinny the Anvil
Post Traumatic Didn't Make The Lakers Syndrome is REAL
JACKASS POWER!!!!!!

[kelpdiver 2]

What's the battery maintenence/replacement cycle like?
What does it take to store 40 Kwh?

That always seemed to be the trouble spot and now residential customers are steered to a system that feeds the grid in the day, draws at night. Doesn't work in remote areas, and it doesn't protect you from power outages.

[Guest]

Billvon,

Very kewl. I especially like the inverter layout - nicely done and well-organized.

Is there a schematic available? I'm curious to see how it's all put together.

Also, I see there are fans in the battery box. Are those to remove waste heat or hydrogen gas, or both? If they're for removing gas, did you find some that are intrinsically safe, or is the accumulation in ppm or some other low level and thus not a factor?

mh

.

"The mouse does not know life until it is in the mouth of the cat."

[billvon 2,434]

Answering several posts at once here:

>Are those solar cells single junction? Dual? Triple?

Polycrystalline are single junction. Amorphous are "triple junction" but that's more a marketing angle than anything else; they are only half as efficient (per sq ft) as the silicon types (polycrystalline and single crystal.)

>What's the battery maintenence/replacement cycle like?
>What does it take to store 40 Kwh?

Replacement cycle is probably going to be 10 years; the bank is large enough (40 T-220 golf cart batteries) that they're not cycled very hard.

>Also, I see there are fans in the battery box. Are those to remove
> waste heat or hydrogen gas, or both?

Both. Experience has shown that you don't need intrinsically safe fans since the concentration stays very low even when the fans fail. (They are intrinsically safe brushless-DC anyway.)

>Is there a schematic available? I'm curious to see how it's all put together.

It is very similar to this.

And the nuclear reactor question? Anyone can build one; they built the first one in a squash court out of graphite bricks. It's getting the fissiles (uranium, thorium, plutonium etc) that's tough. But it would sure make a cool cogenerator.

[bch7773 0]

I think he actually built a gamma radiation gun. its a pretty interesting read on how he did it... but im not sure it would be useful for power generation

MB 3528, RB 1182

[quade 3]

Radioactive Boy Scout

And NPR audio which ran about a month ago.

It's a pretty cool story.

quade -
The World's Most Boring Skydiver

[gremlin 0]

Have been out in California for 2 weeks and haven't seea single solar cell, yet keep seeing news reports about the power problem here and the pollution problem. I would have thought that with all the sun here solar would be an ideal power source.

I'm drunk, you're drunk, lets go back to mine....

[Viking 0]

Quote

Many years ago, when we first moved to Otay........so I installed a little solar power system

I remember that day very well

I swear you must have footprints on the back of your helmet - chicagoskydiver
My God has a bigger dick than your god -George Carlin

[VectorBoy 0]

Quote

Have been out in California for 2 weeks and haven't seea single solar cell, yet keep seeing news reports about the power problem here and the pollution problem. I would have thought that with all the sun here solar would be an ideal power source.

Reliable, inexpensive solar is somewhat new and it will take a while to become mainstream. Ten years ago it took more electrical energy to grow, what was then the common, wafer than the wafer was ever going to give back as solar power in its lifetime. Improvements have been made in the how solar panels are made.
In the seventies we had an rapid expansion of solar water residential installations. This was then and now a very valid and solid home improvement but too many fly by night installers and hacks soured the general public with junk installs. Solar water heatings rep has never recovered.

[quade 3]

Sometimes ya just gotta know where to look. They aren't always this obvious.

This black cube is outside of the Discovery Science Center in Santa Ana, California.

The side that faces south is covered with solar panels.

Sorry for the crappy photo, but this was a drive-by. Well, actually I was stopped at the light when I remembered your comment.

And they have much cooler photos on the web site.

Also see, http://www.discoverycube.org/media/pressKitCube.htm

quade -
The World's Most Boring Skydiver