Undergrad Research Student in need of some Solar guidance

[Duggan419]

should read "5200 watt-hours per day" not 200

[ghurd]

The 1.5.  This is a crappy place for solar. 1.5 hours of insolation a day sometimes.

If I need 5200WH, sometimes I only have 1.5 hours to get it.

The 17 and 12 thing.  12V panels make the max power at 17V.

Say a panel is rated for 17W. Meaning it makes 1A.

Using that 1A it made means using the 1A at 12V.

If it makes 17W, you get to use 12W.

If I need 12W to use, I need 17W of panel.

If I need to use 5200WH/D, I have 1.5H to get it.

To get 5200WH/D, I need 5000 rated watts of solar panel.  Like I said, this is a crappy place for solar.

ie:  I need 18W for 1 hour every day.  That means I need 1.5A of 12V power for 1 hour, meaning 18WH.

To get it takes a 17W (1A) panel, putting 1A into a 12V battery, for my 1.5 hours every day.

The 20% thing.  Batteries are not perfect.  Just because I put 1A for 1 hour (1AH) into a battery, does not mean I can use 1A for 1 hour.

It would be easier to think in amp-hours, instead of watt-hours.

If you need 10A for 1 hour to use, then you need 10A for 1 hour to supply it.

If you need 1A at 120V for 1 hour, you need 10A of 12V for 1 hour. (120V:12V = 10:1)

It will be a lot easier to wade through the math.

Then add 20% to hopefully cover inefficiencies. 5200W x 120% = 6240W.

A good plan will have enough battery to supply the load for around 15 days of load without any charging at all.  Depends on who you ask or where you look.

The 5200WH is 433AH at 12V per day.  Add 20% (because that is what I like to do). 15 days is 7800AH of 12V battery.

Using the common 6V golf cart battery means 72 batteries, at round-about 65 pounds each, for about 4700 pounds of batteries.

Those trailer better be full of money!

Perfectly clear?  ;-)

G-

[ghurd]

Use propane for anything that makes heat.

Hot water. Stove. Heating.

Use solar for the rest.

Don't use A/C.

Might try "solar heat" for the water and home heating.  Like pipes on the roof.

More cost effective than solar electric panels.

G-

[stephent]

Duggan419....

Ever get anything figured out on this yet?

Using Solar cells/PV is kind of a "no-go" as you have figured out.

Using the "C-Van" (container/van) type "trailers" is the smart approach though.

The oil rig fellers have slept..lived in...eat in these things for years all over the globe.

They are tough and take a beating even off-shore.

But for short term usage or right after a disaster happens...using a slightly techinical power type such as Solar would entail lots of stuff being kaput or not work after some time in storage.

Diesel (with stabilizer) or propane will last a long time with few problems.

Batteries, well, lets just say there will be more then less problems.

As to wind power....ummm.... I would hate to see a hastily put up tower with a 10ft whirling prop spinning over my head. Ditto for a large pile of batteries laying close to where I might be sleeping.

Cost aside...all figures aside and even throwing aside the normal Govt thinking that $$ are something to not be considered...It would be impractical at best for what you look to do.

[spinningmagnets]

Just recieved from a friend:

"...The consulting firm I'm working with has been hired by a law firm representing several trailer manufacturers who have been named in a lawsuit arising from hurricane victims' exposures to formaldehyde in the FEMA trailers.  I'm sure everyone has heard at least one news story about this.  

Due to confidentiality I can't go into much detail on this but the interesting part is in what I can say. The approach that the plaintiffs' attorneys have taken is to first test the interiors of the FEMA trailers that haven't been occupied and then test the ones that are now or have been occupied.  

Here's the crazy part:  there are something like seven enormous storage sites in Arkansas, Mississippi, Maryland, and Alabama where over 100,000 unused FEMA trailers are being stored out in the open, in some cases in muddy fields, rotting in the sun and bending out of shape due to poor soil stability.  

In Hope, Arkansas (sound familiar?) the eight full time FEMA-employed guards each have new Ford F-350 dually 4x4 pickups and John Deere Gators so they can guard tens of thousands of unused trailers, presumably from the snakes and the ticks.  

The sale prices of the trailers range from $27,000 to over $70,000 each.  Just try Google Earth and check out Hope, Arkansas.  The trailers are stored at the airport northwest of town.  Keep in mind the trailers shown on Google Earth are a fraction of the number that are currently stored there.  YOUR TAX DOLLARS HARD AT WORK, ladies and gentlemen..."

Here's one of many links:

http://risingfromruin.msnbc.com/2006/08/fema_flipflop_o.html

The formaldehyde is most likely coming from new plywood and particle board used in construction of the trailers.