Solar Power

[mnjrutherford]

Are computer chips used in a basic (read cheap) PV set up? Would they be susceptible to failure from magnetic interference?

[Joseph Lofthouse]

Most PV setups will have a "charge controller" which these days is normally a computer chip. PV systems are less susceptible to electromagnetic interference than the electrical grid due to having shorter antenna lengths... The electrical grid has thousands of miles of wire hanging in the air that can pick up radio and magnetic fields... The typical PV system only has tens of feet of wire to act as an antenna.

[mnjrutherford]

OK, well, that isn't what I wanted to hear... The "behind the scenes" question is this, IF a major magnetic event occurred, major enough to wipe out ALL computer systems... what could we do to keep our car running? I was thinking a solar array might be the answer, but if the chip would be vulnerable, then it isn't a viable option. Mike is now suggesting that we could perhaps encase the computer in lead. But how much lead are we talking about and how big would the container have to be.

[Joseph Lofthouse]

Recent testing on modern passenger vehicles showed that most of them continued running through a major EMP event. And of those that stalled most of them just needed to be rebooted by turning the car off and restarting (sounds like my jeep today). Vehicles are insulated by rubber tires, and they have very small antenna lengths which helps protect them. A grounding strap may also help. Vehicles built prior to the 1980s do not generally have computer chips in them, and the control systems are mostly mechanical and so they are thought to be immune to EMP.

Any device can be protected from an EMP by putting it inside a Faraday cage, which can be as simple as wrapping it in aluminum foil, or storing it in a metal garbage can or ammo can. The perfect Faraday cage would be a sphere. It's hard to use a computer inside a metal box though. Then there are the protections that are often designed into modern electrical devices: surge protectors, lighting arrestors, earth grounds, fuses, circuit breakers, opto-isolators, etc... They all help protect against "Electro-Magnetic Pulses", which are radio waves. We have been protecting our computers from radio waves since our computers were running on vacuum tubes.

I have one room in my house which is a Faraday cage: The walls, ceiling and floor were covered with metal window screen and grounded before sheetrocking. Then the room including doors was primed with graphite paint before the regular paint. If I had it to do over again I would choose a room without a window. People who have aluminum siding on their houses often complain that they have to go outside to use their cell phones. That is because they are living inside a partial Faraday cage.

You were asking about a "magnetic event" and I answered about an "electro-magnetic event" which has been in the news lately.

[mnjrutherford]

Whoa, I had not noticed it was in the news. Interesting coincidence.

Thanks for the in depth answer. I don't know if I've ever heard of a "Faraday Cage" before. We were contemplating acquiring a small fleet (like up to 5) old model VW Bugs. The idea being to have reliable transportation following a major catastrophic event. I'm glad to know that we should be able to rely on our own vehicle. However, secondarily, how would you supply replacement parts and how would you obtain fuel?

We were thinking along the lines that the VW has an extremely simple and efficient motor system. Parts are available after market making it a simple process to acquire a small bank of replacements. There is a place nearby that has dozens of them. We haven't had a chance to go down and find out how much he wants for one or what condition it would be in. But it is definitely on the agenda.

Mike feels that we should be able to acquire a sufficient gas supply for an indefinite period of time. I would rather have at least a couple refitted to use a more available fuel. The best option in my mind being solar.

Have you ever put your mind to thinking about this? I'd love to hear other folks thoughts on the matter.

[Joseph Lofthouse]

If your vehicles had diesel engines you could grow an oilseed crop to burn as fuel. I'm thinking that for my climate canola would be a good choice. With my gas-hog truck that's around 1200 miles per acre.

If you have 5 of the same vehicle model, then you use them as spare parts for each other. If no new vehicles were being made, I'd expect the trade in spare parts and in custom machined parts to be much more robust than it is today.

Golf cart motors, batteries, and controllers aught to be sufficient to power a small vehicle like a VW, especially if you didn't mind slow speeds. Charge it for a week and drive it into town once a week for market....

[bunkie]

that's what ed's working on, plans for a still to make fuel from jerusalum artichokes, sunflowers, etc... that we can grow, for our vehicles and the tractors.

very interesting about the 'Faraday Cage' joseph.

[mnjrutherford]

Ed sounds a lot like Mike. Always up to something beneficial!

[synergy]

I would very much like to have solar power as a summer source of electricity, though I am no where near able to purchase, I also wonder if it would be fried in an EMP event. Also i question if storing items in a rubber lined file cabinet drawer sufficiently guard elecronic items from EMP effects as a faraday cage , or would it need to be grounded further?

I have posted a link for a car adapted to drive off methane produced in a biodigesting tank similar to a septic tank fed animal manure and plant waste:

www.motherearthnews.com/Sustainable-Farming/Methane-Biogas-Powered-Car.aspx

Also this methane/biodigester article tweaked my interest as it seems that an interesting system was built of rather easily obtainable items, that produced a gas for fuel, fertilizer for plant cultivation, and both food production in the way of meat and plant products is a part of the system. And it seems to be a small scale that could be replicated and maintained without too much trouble:

wanderinggaia.com/2010/09/05/guinea-pig-power/

[Joseph Lofthouse]

Nov 9, 2010 11:42:25 GMT -5 synergy said:

Also i question if storing items in a rubber lined file cabinet drawer sufficiently guard elecronic items from EMP effects as a faraday cage , or would it need to be grounded further?

A metal file cabinet is a Faraday cage when the drawers are closed. To test it put your cell phone in the cabinet and call it. If the phone doesn't ring you have a good faraday cage. Grounding it is not necessary, but would add extra protection.

[synergy]

Well I have tried to understand this principal from a layperson perspective and read that houses with plaster and stucco might function as faraday cages, but I do get a cell signal and the phone rings in the file cabinet, so then I thought maybe it is insulated from the ground too much so I put the cell phone inside a metal file box and set it on the basement cement. Also I tried putting it in the middle of a metal veggie grater and so far all I have determined is that I don't know how to really use or maybe even turn on the cell phone? So I will repeat those experiments when my children are home.

I had planned on storing all my information I wanted to access gathered on portable 20 gig USB sticks in case of an EMP but that would be then contingent on having power to run a laptop to access.

Hmm, I might have to buy books again right when I streamlined my house by discarding books in favour of computer files.

We have some solar panels so I am wondering how reliable they might be , surely some research has been done on this ?

[mnjrutherford]

I am very much convinced that we should use a goodly portion of our insurance money from the shed fire to acquire solar power. VERY much convinced. I recognize that a solar water heater is considered the "best bang for buck" (BBFB).

QUESTION/STATEMENT: We need to do it ourselves but were are good instructions (suggest a book?) and were do we buy decent quality components? Can we make components ourselves?

Next, I want solar panels!!!! Yea, they are expensive but I do believe they are a bit less then $5 per watt these days. Even so, that is to much for to little.

Talk to me about making my own panels. I hear that you can purchase solar cells pretty cheap and use them to make your own panels. The price I've heard (but not been able to confirm yet) is $80 for enough cells to make a 144 watt panel which would cost about $700 if purchased ready made.

ALSO heard but unconfirmed is that the homemade panel would run about $150 complete.

I need to also discover the complete list of items needed to have a complete PV system off grid. Our power company does not offer grid tie in so we have to be completely off grid.

[Joseph Lofthouse]

If you have steady winds, and the neighbors don't mind the sound in a windstorm, wind turbines are more cost effective than solar, but wind turbines have moving parts which eventually wear out. Building a wind turbine from commonly available materials is well within the skill set of any tinker. Solar water heaters and solar space heaters are also within the skill set of any tinker.

There are grid-tie inverters that can be used with wind/solar that plug into the wall just like any other household appliance. They work whether or not your power company pays you for excess power. But they don't work if the grid goes down.

The first thing to do when considering converting a house to off-grid electric is to identify what appliances are using electricity inefficiently. Electric heaters, and electric stoves drain too much power to be used regularly off-grid. Consider switching to a propane refrigerator. Consider using power strips to turn things like TVs off when not in use.

[Joseph Lofthouse]

Nov 1, 2010 19:32:57 GMT -5 mnjrutherford said:

Are computer chips used in a basic (read cheap) PV set up? Would they be susceptible to failure from magnetic interference?

Off-grid electrical systems use chips to control charging and discharging of the system and for monitoring it's status, and for converting DC to AC.

The vulnerability of the power grid to electromagnetic pulses comes from having mile after mile of antennas (power lines) hanging in the air to intercept radio waves. Small PV systems do not have those large antennas built into them so they are more resistant to EMP.

To make a PV system even more immune to EMP, apply standard anti-radio interference and standard lightning protection techniques: Bury long runs of cables rather than hanging them in the air. Use lightning arrestors, fuses, chokes, and surge suppressors throughout the system. Install components inside Faraday cages. Use shielded cables and/or run wires inside grounded metal conduit. These are all techniques and materials that are commonly available.

[mnjrutherford]

The winds are not sufficiently steady to use a turbine. Although, I do want to get a turbine as a support and back up to the PV. Our strongest energy source is the sun. We have a perfectly pitched, south facing roof that is 70' x 20'. We are hoping to put a portion of the money towards building a 10' porch across the front of the house that will add another 70' x 11' south facing area that could be used as well.

I'll have to look into the grid-tie inverters you mention. Sounds like that would be just the ticket for us.

Based on the energy audits done last year, all of our appliances are very efficient. Take this statement with a grain of salt because I am only parroting what I was told by the electric companies henchman. We have central heat and air. Heating is supplemented with the fireplace. Another hopeful upgrade will be an insert what puts out more heat using less fuel. AC is supplemented with ceiling fans, electric. I use my electric oven a lot. However, I'm trying to modify my schedule so that I have only 3 baking days per week, occasionally 4 depending on how many customers I acquire. Yesterday I baked 2 batches of yeast bread, an angelfood cake, quaresmali, and sugar cookies. A total bake time of 3 hours 15 minutes. The oven had to be turned off and on a couple times, but I have 2 baking stones so there is not a lot of heat loss allowing the oven to come up to temp very quickly.

As for the stove, I am working on getting a TLUD burner. Making one is not in the cards at the moment, simple though it would be.

Refrigeration... Now that is the big problem. No can do with the propane at the moment. Additionally, what is the future outlook for being able to acquire propane? If we got propane, would we be able to convert it to something else if propane becomes unavailable?

Additionally, we are intending to get a second freezer and fill it with a cow, chickens, and other stuff as the season progresses. Now, that said, we are looking for the most efficient model available and again, the auditor told us that our current fridge and freezer are functioning at peak efficiency.

Will do with the powerstrip on the TV.