Thomas Allen Schmidt's posts

Posted by Thomas Allen Schmidt on Aug 23, 2009 01:23 pm

#61 -  Renewable Energy > RE General Discussion > Re: parallel panels via their junction boxes
Thank you James. I missed that very important point.
Something a spec. sheet doesn't tell.
Indeed, 2 - KC40T's in parallel with the 156% added to their Isc of 2.56 at STC, would add up to 8.268 amps.
Where as I fully understand and respect that these "laws" are in place to keep the likelihood of an electrical fire from erupting to a minimum, I ponder.
If that series fuse rating of 6 amps for the KC40T, is already 1.866 amps higher than the addition of 156% to the Isc of 2.65 amps, which is 4.134 amps, then would it not still be sufficiently protected with only one other KC40T in parallel on a single over current protection device rated at no more than 6 amps? Knowing the extreme set of circumstance involved that would have to happen simultaneously. Alas, probabilities and possibilities.
Probably best that you stick with the NEC Mr. Johnson, what with liability and all being the way it is.
Better safe than sorry, right?

Posted by Thomas Allen Schmidt on Aug 23, 2009 09:12 am

#62 -  Renewable Energy > Technical Discussion: Other > Re: Questions about Siemen panels
It would appear that you are reading open circuit. But it looks good.
Typically speaking, ones power usage is the starting point and the PV array and battery storage are factored from there.
If you go here and choose; Average, Annual, Flat Plate Tilted South at Latitude, you will see that the area you mention receives the equivalent of 6 to 7 kW hrs. per square meter, per day, based on those parameters.
This is a fair assessment, in my opinion, of the the number of hours of equivalent full rated power from a PV module if the lower value, in this case 6, is used based on those same parameters listed above. So -
2 x 48 x 6 = 576 watt hours or .576 kW hrs.
In terms of battery storage that would be -
576 / 12 = 48 amp hours
I like to multiply that by a factor of no less than 5. This would help to keep what is used from the battery over night in the top 20% of discharge and maybe give a few nights of reserve power.
48 x 5 = 240 amps hours of battery storage.
For example: Trojan T-105's are advertised as having 220 amp hours of capacity at the 20 hour rate.
I agree with Michael B that a charge controller is essential and that a battery monitor such as the Bogart 2020 is very helpful in understanding the "ebbing and flooding" tide (metaphorically speaking) of power flow within your system.
Plan for the future.
Oh, there is lightning surge protection to consider as well!

Posted by Thomas Allen Schmidt on Aug 23, 2009 07:43 am

#63 -  Renewable Energy > RE General Discussion > Re: parallel panels via their junction boxes
Its an NEC issue.
That is whats known as "double lugging."
A lot depends on the UL rating of the terminals in the PV modules J-box. Even if each screw/clamp terminal is UL listed as being able to have double wires and its UL listed amperage ratings are sufficient, a lot of inspectors still don't like to see it. What does the manufactures spec. sheet or warranty have to say about it? Anything? Diodes?
Think about how, not just the amperage from the one PV module is passing through the screw/clamp terminal but the amperage of two PV modules. Or more if several are "daisy chained" in parallel. There is also the issue of the UL listed amperage rating of the combiner box, the total amperage, not just the individual PV module circuits. 6 - KC40T's in parallel after the 156% would be close to 25 amps.
(On a side note, something that has always irked me about residential, 15 amp, 120 vac duplex wall receptacles, on a 20 amp circuit, is that little flimsy piece of metal jumper between the screw terminals. In Commercial use, the current carrying conductors must be bonded together with a single "pig tail" that hooks under the screw.)
Of course its not just at the PV modules in your case put at the combiner box which most inspectors will treat just like a power distribution or "breaker" panel. There again some, like the Square-D, QO breakers are made with the screw/clamp terminal that can hold two wires. But a lot of inspectors still don't like to see it and they don't like to see power distribution panels used as j-boxes so a "pig tail" may have to be done in a separate j-box first.
This one in particular.
I hope something here helps you.

Posted by Thomas Allen Schmidt on Aug 21, 2009 02:50 pm

#64 -  Renewable Energy > Technical Discussion: Other > Re: Modified sine Wave VS Pure Sine Wave Inverters.
"I'm putting together an alarm system for my remote off-grid cabin" - "the added features of the alarm is to use modules that will turn off and on lights, etc.It also has the ability to telephone in from another location and turn these modules off and on."

So, a remote off grid cabin in a high crime area, or at least high enough to warrant a security system with all of those features. Remarkable. What is that word that is used for phrases like; jumbo shrimp, and pretty ugly? Anyway, thats what this sounds like to me. No offense intended Paul Smith. It probably comes from my having spent almost a lifetime of sleeping at night with nothing but a screen door between me and the other 6.5 billion other humans on this God forsaken planet. Now if it was say, the Bronx or someplace like that sure but a remote cabin? You should have more to fear from critters than people. But thats just me. I forget sometimes that not everybody is as cavalier as others.
Just the other day I went to tighten the lugs on the main breaker at a fellas house with my hex wrench set and I though somebody had stuck him with an ice pick the way he howled. I told him, I said, "Relax, I have on rubber soled shoes and I know what is and isn't potential to current, I do it all the time." His reply was, "Well, if you want to kill yourself I am not gonna watch." I was glad he left. He made me nervous!
I guess what I am trying to say here is, is the potential for crime really that bad at your remote off grid cabin? I mean most people go remote to get away from all of that kind of stuff. Is there no place safe left on Earth? 

Anyway, to get back to your system.
"you must use the the power adapter as it contains circuitry required to control the modules".
I take it that this system use X10 technology, correct? And it uses the vac to do the switching while it uses the vdc for motion sensors and such? It would seem that it still has a vdc relay the "triggers" the X10. Other than the power adapter getting hot, does the system work ok? I mean, I don't see how this could work at all if the lights and all are powered by one inverter but the security system is power by a different inverter. But of course I don't know what kind of system you have yet.
There are many "pure" sine waves (Which is really stepped, theres just so many steps it can be called "pure.") of low wattages but as Ken Hall pointed out, you may have to experiment to find the right inverter. The manufactures are not going to tell us if its "half voltage" or not. The only way to obtain a "true" sine wave is with a rotating or spinning force, a.k.a, AC generator. Otherwise you may have to look a other security systems that do not require alternating current.

Posted by Thomas Allen Schmidt on Aug 16, 2009 05:49 pm

#65 -  Renewable Energy > RE General Discussion > Re: Solor water pump for 220 gal. water cistern
I found one other place in Virginia that has taken rain water collection and filtration to one extreme.

Posted by Thomas Allen Schmidt on Aug 16, 2009 01:11 pm

#66 -  Renewable Energy > RE General Discussion > Re: Solor water pump for 220 gal. water cistern
Being in Eastern NC can I assume your more of a Pirates fan than a Wolfpack fan?
Unfortunately I could not find anything at ECU. Not that there isn't anything mind you, its ust that I, could not find anything searching their web site. But at NCSU there is this -

As for the showers, a lot would depend on if its 4 season or not. Obviously the NC Summer months might bring enjoyment from a cold shower where as an NC Winter would not. Uhm, other things would include weather or not the capture cistern can be in an place elevated enough for gravity feed low pressures or if would have to be pumped up to the shower head. Of course you will have to deal with the grey water as well.
Also, "Grey water can be recycled for home use."
Other than maybe our pocket book, we are limited only by our imagination when wanting to overcome a diversity of real or imagined obstacles. Have you presented this challange to your "students" to see what they could come up with?

Posted by Thomas Allen Schmidt on Aug 16, 2009 11:33 am

#67 -  Renewable Energy > Technical Discussion: Other > Re: Battery failure on DC powered exhaust fans
To make a long story short, think in terms of averages. If you calculate an alternative energy source such as wind or solar to exactly what it appears you will need, chances are it will fall short from time to time. As well there will be a surplus from time to time. Better to have a surplus more often. Espcially if off grid and the load is a critical one.
You state that your wind resources are minimal although its averages are governed by the same factors, I will leave it out and stick primarily to PV.
As I am sure you already know, the output of your power supply, in this case; PV and wind, is an estimate based on averages depending on several factors but suffice it to say, the weather? Each season has its own extremes as far as weather goes. Summer brings more hours of intense solar radiation and heat as Winter brings less with cold. The geographical location and local terrain as well as local flora can have an impact on those averages.
All of these work hand in hand to create what is known as, "The number of hours of equivalent full rated power from a PV module." Its not an uncommon practice to have to, increase the size of a PV array by a certain factor after its size is calculated. Even doubling it in some extremes.
The link below provides, in my opinion, a fair estimate of those number of hours of equivalent full rated power from a PV module when the lowest denominator is used. But its still not an absolute. The exact, intended site most also be taken into consideration as well.

Myself, I like to use no less than a factor of 5 when sizing a battery bank. My figures would have been -
100 watts / 24 volts = 4.17 amps
4.17 amps x 24 hours hrs. = 100 amp hrs.
100 amp hrs. x 5 = 500 amp hrs. (No less!)
(Not that much different than yours so far.)
To replace that with PV -
I would go to that site and choose; "Average", "Annual" and, "Flat Plate Tilted South at Latitude." (Even if I were contemplating the use of a tracker and mppt controller I would use this.)
In my area the lowest number of hours would be 3. So -
2.4 kWhrs. / 3 = 800 PV array (No less!)
Again, since you stated that wind power is minimal I left those figures out. Think of that as an unexpected "wind fall" when the wind does blow.
Site specifics such as but not limited to; mountains, hills, trees, buildings may cause one to increase this by a certain factor.
So, no less than 500 amp hours of battery capacity and 800 watts of PV (in my area) all at 24 volts nominal.

As for wind -
Unfortunately, I live in one of those areas that show, on a yearly average, a big fat 0. Even though we do, from time to time see a signifcant amount of wind, because of; tall trees, local terrain, soil conditions and, the general rule of thumb that states, "the bottom of the swept area of the rotor should be no less than 30 foot above anything within a 500 foot radius' keeps wind from being a cost effective alternatinve for me. I spent those thousands of dollars on more PV instead of a guyed steel tower and tons of concrete.

Posted by Thomas Allen Schmidt on Aug 14, 2009 08:59 am

#68 -  Renewable Energy > RE General Discussion > Re: parallel ASC shunt controllers
Looking at a spec. sheet for an ASC 12 amp version, its wriiten that "The ASC can be wired in parallel to sub arrays."

First page, paragraph header - "FOR LARGER ARRAYS"

Posted by Thomas Allen Schmidt on Aug 9, 2009 06:07 pm

#69 -  Renewable Energy > Technical Discussion: Other > Re: Equalizing a Bank of Batteries
Provided that the BAE's you have are indeed deep cycle flooded cell lead acid batteries and not the sealed cells, you'll need a hydrometer in order to read the specific gravity of each cell of every battery and they should all read the same. 1.265 on a hydrometer. I am sure Alt-E store sells them. For more information on charge rates for equalizing go here -
and check the "cut sheet" from the manufacture for your particular battery.

Posted by Thomas Allen Schmidt on Aug 9, 2009 05:37 pm

#70 -  Renewable Energy > Technical Discussion: Other > Re: Pole Mounting - Use the Pole as Ground?
Probably not the greatest equipment grounding electrode (ground rod.) I am not sure how its done in your area but, where I am, if we have to drive a "ground rod," if only one 8 foot long by 5/8 diameter galvanized steel rod is driven, it has to be certified by a third party to be at 25 ohms or less or, two can be be driven no less than 6 foot apart, all the way down, no questions asked. But, I am guessing that 6 inch steel pole is a PV array and if its all going back to a grid tied home, it may only need one. This would be up to your "authority having local jurisdiction" (local electrical inspector) of course.

Posted by Thomas Allen Schmidt on Aug 3, 2009 07:26 pm

#71 -  Renewable Energy > RE General Discussion > Re: Looking for information

I would assume that you have read this already but just in case, here it is anyway.
Conservation is the first place to start in my opinion. Reduce what is used and reuse if possible. Use of non toxic renewables of any kind is good.

This magazine goes way back to the early 70's and the Eco movement and back to the land movement. Back before "going green" was a profitable business. There is tons of good howto info in the archives.
I took the liberty of doing a search using "taking care of cats and dogs" and this was at the top of their list.
#14 might be a bit of a, "kick in the head" for you though.

If PV is a serious option for you its always best to have your specific site evaluated by a professional.

If you want to kick around some numbers yourself, start with the shelters monthly electric bill. For example: if the shelter consumes 1,000 kilowatthours per month then divide that by 30 days and that would be 33.33 kWh's per day. If the shelter is in an area that sees a daily number of hours, of equivalent full rated power from a PV module, averaged out over a year of 6 hours, then it would take a PV array of no less than 5.5 kilowatts in size.
Its self explanatory.

Others ideas.
Supposedly this next place is solar powered but I could not find any pics of that. Surprisingly, San Jose sees an average of 5 to 6 hours of equivalent full rated power from a PV module with a "Flat Plate Tilted South at Latitude."

Posted by Thomas Allen Schmidt on Aug 2, 2009 03:04 pm

#72 -  Renewable Energy > Technical Discussion: Other > Re: autotransformers
Might I ask, what are the desired results of this deux autoformer?
Would it be for audio, or maybe battery charging,???
What kind of power is being considered?

Posted by Thomas Allen Schmidt on Aug 2, 2009 02:26 pm

#73 -  Renewable Energy > Technical Discussion: Other > Re: DC Connectors for Battery/Component Boxes
There is a device called, pin and sleeve inlets and plugs.
Typically used in industry. They come in several voltage and amperage ratings most are weather tight. They are dangerous to plug or unplug under load due to an arc flash hazard so a disconnect means is required. I am not really sure if there are any DC rated plugs and connectors. The last time I installed one it was for a portable cotton seed blower that required a 3 phase 100 amp 480 vac circuit but I know the come in other ratings. Check Pass&Seymour, Leviton, Hubble.
Here is a start with what they look like and typical ratings. Remember though, this isn't like plugging or unplugging a 60 watt lamp at the end of your couch. Smiley Use a separate, suitably rated disconnect means on the line side first. 100 amps at 48 vdc nominal is 4,800 watts.

Posted by Thomas Allen Schmidt on Aug 2, 2009 01:41 pm

#74 -  Renewable Energy > Technical Discussion: Other > Re: Will 110V generator run a Shurflo 9325 pump?
Is it known, how many gallons are lost due to evaporation and leeching, in a days (24 hrs.) time?
Obviously this would be greater in the summer than in the winter.
What I am getting at is, there may not be a need to pump water from the well 24/7/365.
If the well can produce 4 gpm without going much below its static level and PV modules will see an equivalent of 6 hours of full rated power in one days (sunup to sundown) time, then 1,440 gallons could get moved in a days time with the right system. Will 1,440 gallons of water be lost in a summers day (24 hrs.)?

Posted by Thomas Allen Schmidt on Jul 26, 2009 07:00 pm

#75 -  Renewable Energy > RE General Discussion > Re: Revolutionary Non-Fuel Electric Engine - NEW - Recorded with U.S. Govt.
No doubt some might argue that it was Nicholas Copernicus that observed the Earth as an orbiting satellite but history tells us the he merely picked up were Galileo was forced to concede to the Vatican under the threat of torture. Similar to but not the same as Guglielmo Marconi being accredited to having invented the radio. We all know now the Marconi's patent was overturned because Nikola Tesla already held the patent on transmitting electric signals wirelessly.

Posted by Thomas Allen Schmidt on Jul 26, 2009 06:41 pm

#76 -  Renewable Energy > RE General Discussion > Re: Revolutionary Non-Fuel Electric Engine - NEW - Recorded with U.S. Govt.
Maybe its just in the semantics but I just can't get past the use of words "electric engine."
To many folks, "engine" and "motor" are synonymous but to me, I relate motor to electrical and engine to internal combustion or steam. Some of us might say, "What size motor do have in your car?" referring to the engine of course but those same people would most likely not say, "What size engine is in your washing machine?" So when I read "Electric Engine" that, sends up a flag, in a manner of speaking and, forgive my ignorance Harold, I don't know wether to salute it or ridicule it. Would there perhaps be a more fitting name? A radial patterned linear motor perhaps? How about, "The Carter Circumlinear Motor?" Or, if it happens to be capable of say, 100 horsepower on a dynamometer, call it the CCL100? Catchy, huh?

Émilie du Châtelet proved Sir Isaac Newton wrong where, the energy delivered by an object in motion is proportional to v2, not v.

Galileo Galilei proved the Vatican wrong where the Earth is not the center of the universe it merely orbits the Sun as many other "heavenly bodies" do. (Something the Vatican did not conceed too until the year 1984 by the way.)

Could Harold Carter be the name that is know for proving Nicolas Léonard Sadi Carnot wrong? Time will tell.

Posted by Thomas Allen Schmidt on Jul 26, 2009 02:16 pm

#77 -  Renewable Energy > For Sale > Re: Revolutionary non-fuel electromagnetic engine - Unique Original New Design
I was able to look at this site Bill. Do you know what a solenoid is and how it works? Same principle. After reading "How it works" the mental image I got was of a "10 cylinder" or better yet, a sequential fire "10 solenoid" motor turning a crankshaft. I suppose the heat of the solenoid is dealt with by some sort of air or water cooling system. There would still be a need for lubrication of moving parts. In a sense, this is really nothing more than a crude induction motor.

I suppose one could go that way, "clickityclackityclickityclackityclikityclakity" or

Of course the "how it works" page makes mention of a 12 volt generator driven from the drive shaft that makes it sound a little to much like the proverbial "perpetual motion machine" to make it all plausible. Laws of thermal dynamics and all that.

All the same Harold, I hope to eat these words one day, if and when I see (hear) an automobile go past me on the highway driven by this type of motor. Best of luck to you.

Posted by Thomas Allen Schmidt on Jul 26, 2009 01:08 pm

#78 -  Renewable Energy > Technical Discussion: Other > Re: Failing PV panels

Posted by Thomas Allen Schmidt on Jul 21, 2009 05:09 am

#79 -  Renewable Energy > Technical Discussion: Other > Re: exhaust venting solar shed with 48v 5 inch fan
I can't tell you to try it but if it were me, I would find something on the order of a single pole electric baseboard heater thermostat, ether a unit mount or wall mount, and try that. But only if it was really cheap or better yet, free. As you may already now, the bi-metal type thermostats just make or brake a circuit. A problem that may or may not happen at 48 vdc, I don't know because I never tried it, might be that the contacts weld together and then you'll be right back where you started with the fan running all the time. Also the temperature range might not go high enough for you. Typically they are from 50F to 80F.

Posted by Thomas Allen Schmidt on Jul 18, 2009 06:06 am

#80 -  Renewable Energy > RE General Discussion > Re: Blemished sharp 170 watt panels
While trying not to sound like a smartalec he said, "Hey, whatever floats your boat!"

Posted by Thomas Allen Schmidt on Jul 18, 2009 05:43 am

#81 -  Renewable Energy > Technical Discussion: Other > Re: Battery bank size
Argh! I couldn't help myself. I hate to be "buttinski." In my defense JC, Sandeep did write to an open community forum. This kinda correlates with my answer to Mr. Birchfeilds question, "More than 4 - 12 batteries in a bank?", in the sense that sacrafices must sometimes be made.

37.5 x 3 x 2 / 24 = 9,375

37.5 kWh's multiplied times 3 days, equals 112.5 kWh's multiplied times 2 (50% of capacity) equals 225 kWh's divided by 24 volts nominal, equals 9,375 amp hours of battery capacity.
If 48 volts nominal were considered that would be 4,687.5 amphours of battery capacity.


Posted by Thomas Allen Schmidt on Jul 18, 2009 04:59 am

#82 -  Renewable Energy > Technical Discussion: Other > Re: More than 4 12v batteries in a Bank?
Think in terms of how a battery is built and how it works.
The most basic battery is a nominal 2 volt cell.
A 12 volt nominal battery is built as 6 - 2 volt cells in series. One cell can go bad and this disrupts the line of chemical exchange in the rest of that battery and any other battery that might be in parallel with it. If several 12 volt nominal batteries are wired in parallel this increases the chance of a disruption caused by just one faulty 2 volt cell within one 12 volt battery. One bad apple does spoil the whole bunch in this case. Its a major chore but, one could periodically remove the wiring harness from a parallel "string" of 12 volt nominal batteries and check each one individually to insure that each battery is up to "par" or, build the same amp hour capacity battery with 6 large 2 volt nominal batteries and if there is a faulty cell you'll know it right away. Its my opinion there is no right way or wrong way, one just makes sacrifices of one aspect in the hope of gaining in another aspect. Of course if a sacrifice is made in order to, lets say, save money in the here and now, then one has to know what the consequences are going to be and follow through to the end. But you already know this, thats why you are here trying to find out those consequences. Seeking the opinions of others that have been there and done that.

The amp hour capacity would come in to play but I would say, if its possible, use 6 - 2 volts cells. Fewer cells to fill, fewer connections to maintain, if one goes bad, you know it right away. But then I don't have a lot of free time one my hands. If I did, I might say just the opposite and possibly save some money in the here and now with 12 volt batteries even though it might cost me more over the long haul if one cell in one battery goes dead and I don't catch it in time to save the others from being dragged down. 

Posted by Thomas Allen Schmidt on Jul 14, 2009 05:33 am

#83 -  Renewable Energy > RE General Discussion > Re: Over 7,000 years of practice...
The past has past on? It has no relevance in the coming future? Dead and gone is the importance of what has gone on before us? That which is important is only what is to come? Just because we can create a thing, therefore by proclamation we must use that thing to the end of the Earth. Its the age old belief that "guns don't kill, people do." Call what you will... Good, evil. God or devil. Right or wrong, it makes no difference what name we give it, it was here before us and it will be here after we have gone. What matters is the time we have and what we choose to do with it. That would be great if it where just me to deal with but unfortunately there are over 6.8 billion others that want to inflict their will, in however small or large of way, over the Earth. The following is believed to have been written several thousands of years ago before human technology came to the forefront of our minds and our obcession for energy to the center of our hearts. Renewable energies is an ansewer, but its not the ansewer. Its a patch used in an effort to keep a gapping, bleeding wound clean.
Call me crazy but I just think there is more to life than persuing every way possible to possess energy here on Earth. Is it not just enough to live here?

Posted by Thomas Allen Schmidt on Jul 11, 2009 12:27 am

#84 -  Renewable Energy > RE General Discussion > Re: DIY Solar Panel Question
There is a saying or a proverb or something, I don't know, anyway it goes something like this, "Give a man a fish and he eats for a day. Teach a man to fish and he eats for a life time." There is a lot to look at in the site below. Take your time be patient and you could find what your looking or. Most of all, just have fun and don't get discouraged if you don't "hook the big one" right away.

Posted by Thomas Allen Schmidt on Jul 11, 2009 12:13 am

#85 -  Renewable Energy > RE General Discussion > Re: Looking to help for FREE !!
The proverbial question when confronted with the task of acquiring meaningful employment and the prospective employer requires experience. "How do I get experience if I can't get a job doing the work without experience?" It happens all to often. Here is a link to a web site that might help with a knowledge of what prospective employers are up against. Maybe you can find a niche in there somewhere that is close to something you have experience in and hopefully get the proverbial "foot in the door."
There is more at the bottom of their page.

Here is a list of sites to help locate dealers and installers. If anybody is going to have projects, and the potential need for help, they will! Can I offer some friendly advice? Don't sell yourself too cheap! Offer yourself at a reduced rate in exchange for OJT (On the Job Training.)
I'll just stick a few more links up here. Maybe you can find something worth while in them. (check installer locater)
Keep up with the latest news...

Use those online search engines, type in all kinds of stuff like; "ongoing solar installation in New Hampshire", or "Solar installations soon to be completed in New Hampshire", stuff like that will lead you somewhere and you might find links to other places.
On a hunch I tried that first example myself, read through, tried a link and found this -
Best of luck to you Albert Disciullo!

Posted by Thomas Allen Schmidt on Jul 10, 2009 10:52 pm

#86 -  Renewable Energy > Technical Discussion: Other > Re: Problem with Trace C-60 charge controller.
Thanks Jon C.
The LED indication of a circuitry overtemperature never happened with this C-60. It didn't even feel warm. What led me to try the fan was, 1 - elimination of all other possible problems and, 2 - the short on/off cycling in ether mode. After a consult with a Xantrex tech. rep. it was determined that the unit be replaced. I can only speculate at the probable cause for this damage... Most likely a nearby lightning strike.

Posted by Thomas Allen Schmidt on Jul 5, 2009 05:54 pm

#87 -  Renewable Energy > Technical Discussion: Other > Re: Controller for operating loads both with solar and ordinary power
Wow, I had forgotten about this one. You're right "Tech Guy" the topic was deviated from a little. Thats my fault.

You are looking for answers to living with less utility generated electricity from burning coal or nuclear power plants. It that correct?
You want to stay on the grid "utility power" but produce your own electricity from photovoltaics and possibly store some of it in batteries for use at night. Is this correct?

Assuming that these are correct, the point I had in mind, when I wrote that post, with that link, was a crude attempt to show you a path that does not include the grid at all. Its called living "off grid." We (humans) had lived "off grid for thousands of years. Now look at where we are only 100 years after having a "grid." We are trying to "save the planet" with renewable energies. It would seem to me that if we really wanted to "save the planet" we would just, turn those energies off. We are not going to have these energies without consuming some natural resource (mass) or other. Its that simple. Would billions of people die within 100 years of doing so? Most likely but that shows us just how fragile a thing being so dependent on these manmade energies is.
As for exploiting the week. Thats just human nature now isn't it? What do you think being made dependent on these manmade energies does? It does not empower us, it makes us dependent on those that can produce it or, supply the mass or for those that produce it or, the means for us to produce our own or, supply the mass to produce those items. PV modules and the supporting electrical do not last forever and the last time I looked PV modules and copper wire and wind generators, etc. etc. do not grow on trees.
(For you John D. )

Recently on another thread, "Tech Guy," you asked about equipment for megawatt PV systems.
Have you considered seeking out (paying for the services of) a professional in photovoltaic electrical systems "Tech Guy?" There are so many things to consider when designing and building a PV system that, no matter how knowledgable and/or how good the intentions are of people on this bulletin board, someone could inadvertently give you bad advice. This is why, here in the USA, we have things like; the NEC and, state licensed electrical contractors, permits and, inspection by local authorities and professionals (for hire.)

"Fear is not in the habit of speaking truth; when perfect sincerity is expected, perfect freedom must be allowed; nor has anyone who is apt to be angry when he hears the truth any cause to wonder that he does not hear it." ~ Cornelius Tacitus, Roman senator and historian - 96 AD.

Posted by Thomas Allen Schmidt on Jul 4, 2009 09:36 pm

#88 -  Renewable Energy > Technical Discussion: Other > Re: Is charge controller available for 120V DC system?
I found this on another discussion board so...

If its true, you would still need what, about 12 of them?
I tried to download and read the manual myself from Outback but it was corrupted.

Posted by Thomas Allen Schmidt on Jul 4, 2009 08:27 am

#89 -  Renewable Energy > Technical Discussion: Other > Re: Is charge controller available for 120V DC system?
Ok, I was a little confused at first by how you were asking about 120 vdc PV charge controllers on something such as the Alt-E Store community forums but I let it go and went with the flow. Now your asking about integrated components for large scale photovoltaic power plants. That along with a "guy" that wants to remain anonymous has got my "spidey senses tingling" if you catch my drift. 
I do not assume to speak for the Alt-E Store but I would like to say, it would seem to me that the Alt-E Store is primarily residential and commercial PV system oriented. More so than utility scale PV power production anyway. Please forgive me Alt-E Store if I have crossed a line here.
There are places that cater to the utility scale PV systems operator. Perhaps you can find what you are seeking at one or more of these sites? Or at least links to other sites.

Personally, I would think that a more efficient way of storing power from a utility scale PV plant for night time use would be hydrogen instead of lead acid batteries.

The following news clip is almost a year old but maybe you could find one near you and arrange a tour?

I hope that something here helps "Tech Guy."

Posted by Thomas Allen Schmidt on Jul 2, 2009 12:17 pm

#90 -  Renewable Energy > Technical Discussion: Other > Re: Is charge controller available for 120V DC system?

my system size is 40KW.

A PV array of 40,000 watts at 120 vdc nominal?
Thats still 333.33 amps without the UL/NEC 156%!
If I multiply that by 4 hours of equivalent full rated charge we are looking at 1,333.32 amp hours at 120 vdc nominal!
If I multiply that by a factor of 5 to size a battery bank, thats 6,666.6 amp hours at 120 vdc nominal battery bank!

Industrial motor controls use magnetic starters. For example; a 120 vac single phase, less than 1 amp draw coil, is used to "pull in" a starter that connects a higher voltage and amperage motor circuit like say, 480 vac 3 phase at 100 amps. An automobile starter works on this same principle only they are all they same voltage, just higher cranking amps. Old timey cars and trucks used to have something like the old foot operated headlight high/low switch only the foot operated stater button was normally open and momentary and it connected the full amperage from the battery to the starter when depressed. The key switch simply turned on the ignition. But enough of that.
If one could build a sensor that could read 120vdc nominal battery voltage as compared to 120 vdc nominal PV array voltage and make the high/low setting field selectable and that could "pull in" or "drop out" several contactors of a higher amperage rating in accordance... Your problem would be solved. This would in effect be a simple on/off charge controller technology similar to the Trace C30's. One problem would be that at higher dc amperages, the contacts have a greater tendency to weld together. This might be overcome by reducing the amprage with several sub-arrays and multiple contactors. If one does weld together, enough of the other contactors could open there by reducing the over all charge. As with any system of this nature redundancies and alarms may be necessary. PLC's would be a nice touch. Just an idea.

This is the closest thing I could find to what you are seeking that is, more or less, "off the shelf." It actually does more than what you may need but as James pointed out, a custom piece may have to be built. Good luck!

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