Thomas Allen Schmidt's posts

Posted by Thomas Allen Schmidt on Apr 8, 2009 05:32 am

#151 -  Renewable Energy > Technical Discussion: Other > Re: Battery State of Charge
No, no your all wrong about us. We don't have to constantly monitor the battery state of charge. Sure, at first we did leave the battery monitor (in the wall by the front door light switches) set on "battery percent of full." But as time went by (maybe a year) we learned the "personality," for lack of a better word, of our system.
So now we, no more have to constantly monitor the battery state of charge than we have to constantly monitor a clock to know what time it is or a calender to know what season it is.
Now, if we want to pin point battery state of charge we can and, we do but thats no different that using a clock to pin point a time of day or a calender to pin point a day of the year.
We watch the weather like most folks I know. If its the middle of winter and the weather man is forecasting a week of overcast (sunless) weather, we check the battery state of charge and we just, know, how much or how little to start conserving power. Just like how you, knew, that overcast is synonymous with sunless. I didn't have to tell you that.

Can we agree that the battery monitor is a tool just like your VCS, each has its own unique purpose? By the way, what alarms? I didn't know we had a large battery bank. I don't know wether to feel special or feel like a glutton. Is 1600 amphours at 12 volts nominal, for a family of four; two adults and two teenage girls (who by the way have lived their entire life "off grid") living on a more or less self sufficient farmstead, considered large? Our amphour draw in a 24 hour period can flcuate from 100 to 400. Typically around 200 amphours. Which if you condiser a lighted billboard along the I-95 corridor that has; 2 - 400 watt MH lights that burn for 10 hours every night, thats 8 kWh's. In compaerison, we typically use 2.4 kWh's over a 24 hours period to power our entire place. I thought that would be considered small. Maybe not?

Posted by Thomas Allen Schmidt on Apr 7, 2009 05:49 am

#152 -  Renewable Energy > Technical Discussion: Other > Re: Battery State of Charge
Sorry solarjohn but I have to respectfully disagree, adding another piece of electronic/electrical control equipment may be another option but "bottom line" it is not.

We don't have, nor have we every needed, an automated LVD on our inverter circuit, or any other circuit, and our batteries have never hit bottom! They have come close on a few occasional weeks of different years during winter months and, we didn't use a generator ether. (We live off grid and don't even have a generator.)
We did however make good use of our Bogart Tri-Metric monitor that is mounted in the living room wall by the front door light switches. When battery percent of full gets low (below 50%) we simply conserve more. Its become almost second nature and mind you, this is only during extreme weeks of some winters and we are not stumbling around in the dark or burning candles or kerosene lamps. Just a little less time on the internet, a little less time watching TV (stuff rots your brain anyway Smiley ), maybe all in one room reading instead of separate rooms, things of that nature.
I suppose, in all fairness, I should add that we had lived off grid without any type of electricity for over 25 years before we went PV. This could be a big difference also.
So far we have only had to replace a bank of Trojan T-105's but we got the better part of 8 years of household service from them. They are still in use, just not powering the home anymore. Time will tell how successful we are with the new bank of Surrette 530's. I hope to get at least 20 to 25 years of actual household service from them.

Living day to day in a household with electricity coming from battery power, is about, more than just battery voltage. One has to consider the number of amphours removed and how they are replaced as well as the number of cycles built into the battery and the relationship of shallow or deep cycling. Sure there is always going to be some gizmo or gadget for sale to do it for you or there is just plain good ole common sense. To me, saying "the misery of battery stage of charge." is like saying a cat is miserable with a mouse.

Posted by Thomas Allen Schmidt on Apr 5, 2009 06:00 am

#153 -  Renewable Energy > RE General Discussion > Re: Solar is a sellers market after all:(
There is something else to consider as well.

Posted by Thomas Allen Schmidt on Apr 5, 2009 05:46 am

#154 -  Renewable Energy > Technical Discussion: Other > Re: Battery State of Charge
Most of the 12volts inverter cutout the battery at 10.5volts to prevent over discharging.

It all starts with knowing in advance what the anticipated power requirements are. Not what the batteries bottom line is. A well thought out and sized system should never come to this.

Although it is recommended by some that, battery to inverter cables be sized according to the maximum sustained wattage output of the inverter at the lowest possible voltage. Example - 1500 watt continuous at 10.5 volts equals 143 amps. This would be the amperage to start all other wire sizing computations from, such as line loss, for battery to inverter cables.

More importantly, a battery bank should be sized by a factor of nothing less than 2 times the expected highest amphours draw between recharge cycles. Personally I prefer nothing less than a factor of 5. This improves the odds that the low voltage cutoff never comes into play.
Instead of focusing on a batteries absolute bare minimum, focus on keeping it within, at least, the top 20% state of charge between anticipated recharge times. In other words "aim high." This is where a battery state of charge monitor, placed where it can be readily seen by all who use the power, is essential to system well being and your state of mind.

Lets say for example that all of your computations have told you that a battery capacity of no less than 440 amphours is required to get you through one night. Simply multiply that 440 by a factor of 2 or 5 or more. Of course budget may dictate this, but absolutely no less than 2. This will help to keep it in the top 50% state of charge. A lot will depend on the means by which the battery or batteries are recharged. Choosing the means of and, sizing that correctly will have a significant impact as well.

Think about the performer who is spinning a plate on top of a stick, he or she is not thinking about that plate crashing on the floor, he or she is thinking about keeping it spinning on top of the stick.Smiley



Posted by Thomas Allen Schmidt on Mar 31, 2009 05:07 am

#155 -  Renewable Energy > RE General Discussion > Re: During Float Charge - How to use the extra PV power?
My bad.

The picture that comes to mind is of the proverbial squeezing and rolling of the tube of toothpaste.
I agree though, it is a waste of potential.

When a PV system is actually planned and designed for offgrid. It usually means there is a surplus of power in the summer months and it just squeaks by in the winter months. This of course is dependent on local.

But what to do with the power from a PV array that, is not, going to the batteries during the float stage of charging and, its still relatively early in the day?

I suppose James A. hit on something there, but what if it was a smaller secondary battery bank sized just big enough to capture the otherwise lost power and then use it at a more convenient time? (May want to oversize the bank a just a little.) It might mean putting the, charge controller to battery, circuit on an automated transfer switch.
Sounds a little "mad scientist" I know but its not as though you will be staring at the battery monitor, yelling to a hunchback named Igor waiting to throw the transfer switch at just the right time.
Thats all I can come up with right now.

Posted by Thomas Allen Schmidt on Mar 27, 2009 01:55 pm

#156 -  Renewable Energy > RE General Discussion > Re: During Float Charge - How to use the extra PV power?
I am curious about the remark you made concerning "net metering." Does this mean you have a grid intertied system with batteries as a back up power supply?

Posted by Thomas Allen Schmidt on Mar 27, 2009 01:42 pm

#157 -  Renewable Energy > Technical Discussion: Other > Re: Solar system for workstation computer.
No problem Francisco.
Typically, my computer and monitor will draw around 11 amps at 12 volts dc nominal, from my 600 watt Samlex pure sine wave inverter. This is at night when, of course, there is no sunshine so its all from the batteries.
11 amps X 12 volts = 132 watts
So for each hour that it is on, being used, thats .132 kWh's. If I am on the computer for 8 hours that would be,
8 hours X .132 kW's = 1. kWh (By the way, a power company might only charge about $0.12 for that.)

Now to figure out what it would take to create an off grid dedicated PV system just for that (and maybe a small desk lamp), I would look at the 11 amps and multiply that by 8 which is 88 amp hours. To size a battery bank I would at least multiply that 88 amp hours by a factor of 5 so that, what is used from the batteries is only the top 20 percent of battery capacity. Doing this helps the batteries to live an over all longer life and it is easier for the PV array to recharge them the next sunny day.
5 X 88 = 440 amphour battery bank at the 20 hour rate.
Remember, this example is at 12 vdc nominal.

Your location would have about 5 to 6 hours of equivalent full rated power from a single PV module.
This is based on an average over one year with the PV module mounted at an angle equal to the latitude, facing solar south. What this means is, if it where a single 100 watt PV module, in a whole days time it might make as much as .5 kWh's. There are a lot of factors to take into account for your exact site like; trees, buildings, smog, and of course, the weather.
Now to figure out what I would need for a PV array.
I would take that 1. kWh and divide that by 5 hours of equivalent full rated charge, 1000 / 5 = 200
So at the very least I would need a 200 watt PV array. I would probably increase that though. Maybe even double it to a 400 watt PV array. Doing that could make a big difference in keeping the battery bank in the top 20 percent of full charge on those cloudy days and such.

From this example I would know that if I wanted a dedicated PV system for my computer I would need at least a; 400 watt PV array, 440 amphour battery bank, 200 watt pure sine wave inverter and of course, PV array mounting, charge controller, wire, conduit, breakers, fuses, disconnects, etc., etc..
There is quite a bit of stuff to safely conduct all this power and you will need to know the correct size and type wire, breakers and, such for each particular use such as PV array to charge controller or batteries to inverter.
Me personally, I keep a fire extinguisher near my stuff. You just never know when or why but something can happen. I have learned that, when dealing with electricity its not so much a matter of probabilities as it is possibilities. It may not happen but it can happen and thats enough for me. One can reduce the probabilities of an electrical fire greatly if one follows the NEC. (National Electrical Code)

My only advice to you Francisco is, if you plan on designing and installing your PV system yourself, take your time now and learn all you can about safely conducting electricity. If you are not, or don't have a friend, that is an electrician familiar with the NEC, make one or learn the Code.

Some more places to learn are;
(Look accross the top of the page at the above site and go to "publications" then scroll down to "codes" and go to "John Wiles code corner." These articles were written and published in Home Power magazine.)
and then there is,

Posted by Thomas Allen Schmidt on Mar 27, 2009 06:21 am

#158 -  Renewable Energy > Technical Discussion: Other > Re: Solar system for workstation computer.
If your not in any big hurry to have a PV (Photovoltaic) system, you could learn a lot from its full of articles from people who have built there own PV systems or have had their PV system built for them. Both large whole house off grid PV systems and small dedicated load PV systems.
Take a look. There are advertisements for PV system sales, service and, installation contractors.
Here is a place, Its in Victorville, CA. about a 2.5 hour ride from Oxnard CA. If you get out that way it might worth the time to check it out. They have some pretty good prices on PV and related system devices.
You will want to know just how much power your computer requires for the amount of time it is to be on in kWh's (kilo-watt-hours). There are simple kilowatt recorders that plug into a wall socket and you could plug in your computer system to the kilowatt recorder. Here is an example of one but you might be able to get it locally and cheaper at a home improvement/building supply store. Here is another place you could try to find a PV dealer/installer closer to you.

Posted by Thomas Allen Schmidt on Mar 22, 2009 11:09 am

#159 -  Renewable Energy > Technical Discussion: Other > Re: economic solar water pump design
Yeah, chances are good that all of these types of water pumps are going to be expensive, in my opinion, thats why I threw in that alternative of using a hand operated water pump. Its not any cheaper but it, I think, gives you all more options for the future.
If we work with the figure of 480 gallons of water per day and assume that each stroke supplies 1 pint of water per 2 seconds that comes to 225 gallons per hour or 3.75 gallons per minute.
If you take a look at that website I gave you a link too again you should see that their claim is to 3 gallons of water per minute. So it would take about 2.5 hours of pumping by hand to fulfill the 480 gallons desired. Considering that all pipes are full to begin with.
It also gives you the option of changing over at a later time to solar power. There are links within their website the can help you determine the best application for your site should you consider it.
Its not as hard as you might think to pump that much water by hand. It helps if one is ambidextrous. In this particular case thats not a hard "skill to acquire. As it turns out, necessary.
To be sure there is several people in this, uh, village? that would not mind a "workout" of this nature. They could take turns. Something I wished I had when I was filling 6 - 55 gallon drums with a pitcher pump. There is no doubt that this is a mundane task but so is an 8 hour day 5 days a week job, yet billions of people do it world wide there entire adult life. Many of them have to sit on there butts the whole time. Tradgic if you ask me. Somehow, I don't think thats what God intented for the human physique.

As for the 4.5 hours a day of peak sun hours. That may be the same as what I call the "number of hours of equivalent full rated power from a PV module." Mr. Winters explained this in his post. LCB's (Liner Current Boosters) help to "stretch out" that 4.5 hour solar day when a PV direct pumping system is set up.

One other plus for that hand pump is it can be done at night as well, when its little cooler outside.


Posted by Thomas Allen Schmidt on Mar 22, 2009 07:19 am

#160 -  Renewable Energy > Technical Discussion: Other > Re: Battery care for summer camp
I like David Ames ideas but you'd be losing almost half the potential of the PV system.
Its a shame you can't make it all portable and "plug it up" at home or cabin.
From basic,
to extreme,
and somewhere in between?

Just another alternative.

Posted by Thomas Allen Schmidt on Mar 18, 2009 06:53 pm

#161 -  Renewable Energy > Technical Discussion: Other > Re: Questionnaire for site surveying to install a solar PV system
I have never seen one with all of that on it but thats not saying there isn't one. If your interested in starting up a PV supply and installation service, a good place to start learning is here...
It may involve getting an unlimited state electrical contractors license as well. Check with your state.
Best of luck!

Posted by Thomas Allen Schmidt on Mar 18, 2009 06:09 am

#162 -  Renewable Energy > Technical Discussion: Other > Re: economic solar water pump design
Wow, I am surprised no one has ansewered this one yet. Have you found what you need Todd Bauer?
Something that I would have a concern over would be the recovery rate of the well. Your desire for 1 gpm would be 480 gallons in an 8 hour day. With only 2.20 meters of water in the well it would seem that it would have to be really big around or have a really fast recovery rate. For a long time I used a pitcher pump to fill plastic drums on an elevated platform from a shallow spring fed cistern well. If I remember right it only took me about an hour to fill 6 - 55 gallons drums. Got a nice little work out at the same time.

This isn't the type I used though. The type I used was the more commonly seen cast iron type with the leather washers. I should add to that my pump and tanks were only about 4m high and the well about 4m deep.

Posted by Thomas Allen Schmidt on Mar 18, 2009 05:45 am

#163 -  Renewable Energy > RE General Discussion > Re: Have been preparing for solar...
Good morning Ronald Ronpbruner.
Here is a place to take a gander at.
If that one don't float your boat you can try this one.
Of course, if your looking for a personal endorsement, I can't give you one.
Good luck!

Posted by Thomas Allen Schmidt on Mar 18, 2009 05:28 am

#164 -  Renewable Energy > Technical Discussion: Other > Re: AC amps - DC amps
Hey Dave.
A little while back I asked if your generator has a capcitor bank on it. Take a look at this report by Xantrex and maybe this will clear up some more stuff for you.

Posted by Thomas Allen Schmidt on Mar 16, 2009 11:15 am

#165 -  Renewable Energy > Technical Discussion: Other > Re: How to calculate the inverter size for a 5kw system?
I would have more questions than ansewers Rajesh Kumar.
If your battery banks is at 48 volts nominal and the PV array experiences up to 4 hours of equivalent full rated charge per day on aveage for the year, then your looking at the potential of somewhere in the vicinity of 400 amphours. If your battery bank is sized to stay in the top 20 % of full charge per 24 hour day/night cycle then you would have a 2000 amphours battery bank at 48 volts nominal.

Using the figure of 400 amphours daily though and assuming all loads are to be vac from the inverter then you should have somewhere in the vicinity of 20 kWh's total. If you utilize a 5,500 watt inverter at maximum potential it might run for about 3 hours. Or any variation of this. Such as 2,750 watts for about 6 hours and so on and so fourth,

As with most renewable energies that rely on the weather, your "mileage" may vary. Know what I mean?

Posted by Thomas Allen Schmidt on Mar 14, 2009 09:45 am

#166 -  Renewable Energy > Technical Discussion: Other > Re: Connecting to AET piping
I have not used this product but it sounds credible.
As usual, its best to consult with the manufactures first.
Here is somebody that should know with a degree certainty.

Posted by Thomas Allen Schmidt on Mar 14, 2009 09:12 am

#167 -  Renewable Energy > Technical Discussion: Other > Re: Battery / Off-Grid system
Hey, Andrew Rasken.
Jon C. pretty much summed it up for you.
There is no "Code" within the NEC (National Electrical Code) that I am aware of that dictates where the change should occur.
There is no mathematical formula that decides where, for example, a 12 volt nominal system should stop and a 24 volt nominal system should start and so on.
But think about it this way...

If you have a 5000 watt PV array wired for 12 volts nominal you will have to provide ample size conductors and supporting electrical devices like fuses, breakers, charge controllers, and all in order to safely utilize a total of 400 amps, give or take.

That same 5000 watts at 48 volts nominal would equal only 100 amps give or take. This translates into big $$$ savings.

IMPORTANT NOTE!(These are not real world examples of an actual PV system. These are examples to help illustrate the gist of Ohm's law.)

Its not just for PV arrays ether. This applies to all electrical installations from the biggest nuclear power plant down to the battery in kids small toy. If you would like to learn more, just search - Ohm's law and then price the difference between 500 mcm and #2 - copper wire per foot.

Another important fact that Jon C. pointed out is power loss. When speaking in terms of conductors, such as but not limited to wire, Lower voltages suffer a much higher rate of power loss over a compareable distance to a higher voltage. This is the sole reason that Tesla won out over Edison in the AC vs. DC war.
Alternating currents can be transformed by way of inducing the current flow from one set of windings (pronounced: wine-dings) onto a different set of windings because it is constantly going from, pos. to off to neg. to off and so on. Think about those high tension power lines you see all over the country side and in the cities. Chances are the are carrying some where around 200,000 vac more or less but by the time it gets to a typical home its been transformed several times down to 120/240 vac. Each time the amperage increases. (Not taking into account the number of "taps" for a multitude of homes and business's or industries.)
An example of this in a Direct current can be found in the ignition system of earlier automobile engines. One set of windings inside the coil receives 12 vdc through the closed points but when the points open (turn off), the electric field inside the coil collapses and is induce on another set of windings that provide nearly 10,000 vdc potential to the grounded spark plug gap. But it is at a much lower amperage than the 12 volt line side.

If your really interested in an RE system for your home or whatever, I can tell you, one of the best investments that I made was a subscription to it had the greatest payback value of all in my opinion.

Posted by Thomas Allen Schmidt on Mar 9, 2009 06:26 am

#168 -  Renewable Energy > RE General Discussion > Re: What is energy?
It is easy enough for you and I to keep repeating ourselves essentially saying to one another "I am right and your wrong" but somehow, I think nobody at this forum really cares. On what grounds do you assume to stand over me and ask that I validate myself Gina Roberts? You have offered no such validations on yourself. You have only asked that we pity you for your flu.

Take care of yourself Gina Roberts. Flu virus's are something that never really go away. We only build up an immunity to them or they build up an immunity to our medications. (Do I get an argument on that?)

I apologies to the readers of this forum if my behaviour here has put anyone at odds, including you Gina Roberts. It was not my intent.

If there is anybody following this thread and you want to know more about the physics of mass and energy and make up your own mind, just look it up and learn. You decide which is real and which is an illusion. Watching us pick nits and arguing for the pure sake of arguing is not a means to an end. It is simply, arguing.

Good bye.

Posted by Thomas Allen Schmidt on Mar 9, 2009 05:20 am

#169 -  Renewable Energy > Technical Discussion: Other > Re: garage door opener
Hi Kon Pik
Sounds to me like you want start small and learn from first hand experience. I can respect that. There is quite a bit of stuff to learn believe it or not and, it is possible that things could go horribly wrong and you have a fire or, at the very least you will have bought ether not enough or too much equipment or "gear" as you put it.

This is what we know.
1 - 24 volt - 1.2 amp hour capacity battery
I can only assume 4 amps is the door openers, motor name plate rating and the 7.5 amps for 3 seconds is the start up surge. It can run through 10 open/close operations per (12 hr.?) day on battery power alone.
How long does an open/close cycle last? Not including the time it takes to drive the vehicle in or out. 2 minutes to open, 2 minutes to close? 1 minute each?

If this one battery can do all of that then all it needs is a very,very small maintenance PV battery charger. I agree with Mr. Winter's recommendation of the 2 - 1 watt PV modules in series. Even then you may not want to put them in full sunlight all day long. Maybe just catch a few hours in the morning. You'll have to experiment with that and hope the battery doesn't overcharge, swell up, and bust. To be honest with you, I don't even know if anyone makes a charge controller that "small".

Does the door openers manufacture have any recommendations?

Posted by Thomas Allen Schmidt on Mar 8, 2009 02:07 pm

#170 -  Renewable Energy > Technical Discussion: Other > Re: Hot breakers
A simple formula that I use for sizing PV source circuits is as follows.
Take the sum of the PV modules rated short circuit amperages and multiply by 156%.
In your case I believe that would be somewhere in the vicinity of, 5.47 Isc.
7 X 5.47 x 156% = 59.73
This would be the number I use for any other calculations concerning the sizing of wire. In addition to line loss, other considerations are; type if insulation, temperature deratings, number of conductors in a conduit, etc., etc.
But thats just my way.
Here is a link with a lot of useful information concern PV practices and the NEC.

Um, is the 63 amp breaker 1 - two pole or 2 - single pole breakers? If it is 1 - two pole breaker there might be some eddying of currents going on internally causing the heat. Heat in any conductors (not just the wires) of electricity is typically a sign that there is resistance due to poor conductivity. Check the temperature ratings of the breakers. It might pay to purchase or barrow a temperature probe. Such as, but not limited to, this one.

Posted by Thomas Allen Schmidt on Mar 8, 2009 12:29 pm

#171 -  Renewable Energy > RE General Discussion > Re: What is energy?
As for the speed of light, I would defer to  "the Heisenberg uncertainty principle" that says you cannot simultaneously know the exact location and the exact speed of anything, including atoms. 671,000,000 miles per hours is just a number I threw into the "ring" as an indication of reference. My apologies.

As for any philosophical or spiritual connection to our being creatures of light. I suppose there are some in a romantic sense but for the sake of this thread its intent was used for the purpose of illustrating that we and everything around is a part of the known universe and that we and everything around us in that known universe is made of the same "stuff", call it, "stardust" if you like and light being the most purest form of that "stuff", nothing more.

Now as for gravity and molecular cohesion being one and the same. I will leave that "up in the air" for its has nether been prooven or disprooven. That is why it was framed as a question not a statement of fact. If what we know as the electromagnetic spectum is in actuality a continuum, then why can't macroscopy and microscopy also be a continuum?

Is it so incredible to want to believe that where and what we are in this seemingly endless universe is just the smallest part of something way larger than we could ever conceive of? While in the same instant of time the largest part of something smaller than we could ever conceive of?

"We should take care not to make the intellect our god; it has, of course, powerful muscles, but no personality."
Albert Einstein. Smiley

Posted by Thomas Allen Schmidt on Mar 7, 2009 01:14 pm

#172 -  Renewable Energy > RE General Discussion > Re: What is energy?
Thomas, Einstein 's theory of relativity referred to rest energy mass, E.

His point was that there was some amount of energy proportional to the mass of body...E=mc2.

Mass is matter!

Mass is not energy!

Energy is mass and mass is energy is a new theory, Thomas, not dear Einstein 's...
mass can be destroyed...
energy cannot,only transformed into another form..

Exactly. Einstein showed that mass and energy are really two different forms of the same thing; the "vanishing" mass of the protons and neutrons is simply converted to energy.
 Now, think about what happens when mass is "destroyed," as you say. It does not disappear from the universe. It is still there. Perhaps in a different state such as particulate solids or maybe as plasmas. Maybe some other state that we humans and our limited knowledge of the electromagnetic spectrum cannot discern as of yet. Without knowing which mass and its type of "destruction" I cannot even guess but nature is a closed system. If we could add up all the mass and energy that's around before and after a nuclear reaction, you'll find that the totals come out exactly the same.

Matter - That which has mass and occupies space.
Mass - The property of a body that causes it to have weight in a gravitational field.
Energy - A thermodynamic quantity equivalent to the capacity of a physical system to do work and vice versa.

So if we are to believe that mass and energy are not one and the same then which came first?
Unless of course you think that energy and mass just appears from nowhere by some miracle or perhaps, sorcery. Sorry.
As far we know mass consists of matter which consists of known elements which have their own atom and when an atom is split the result is a release of energy. 

We and everything in the know universe consist of matter or mass or elements or energy or light its all the same, only each in its own right, or by will of God, is distinct and unique.

"I want to know God's thoughts; the rest are details." Smiley

Posted by Thomas Allen Schmidt on Mar 4, 2009 08:28 pm

#173 -  Renewable Energy > Technical Discussion: Other > Re: AC amps - DC amps
I thought about this after I posted.
Its educational as well as entertaining.
You might still want to put on a pot of coffee. Just in case.

Posted by Thomas Allen Schmidt on Mar 4, 2009 08:10 pm

#174 -  Renewable Energy > Technical Discussion: Other > Re: AC amps - DC amps
Oh, okay.
Anytime voltage is decreased with a given wattage, amperage goes up. Likewise if the voltage is increased with a given wattage the amps go down.
4000 watts / 120 volts = 33 amps
4000 watts / 24 volts = 167 amps
Of course the reason your only seeing 60 or so amps is because of the windings ratio of the chargers transformer.
60 amps x 24 volts = 1440 watts

Go here
and scroll down to such things as;
Faraday's Electromagnetic Induction Experiment,
AC Generator Action,
DC Generator Action,
Ohm's Law, (Watts can be construed as resistance at work.)
How a Transformer Works

I don't know. Maybe you know this already.
 This wavelength is drawn two dimensionally. In real life or 3-D its more like a Slinky kinda strechted out.

Its interesting to note that the small portion of the electromagnetic spectrum we humans know is like a grain of dust to the planet Earth. Its a continuum.

Sorry. Getting off the subject. I'll let you digest this and hope that I haven't skipped to much. Its all kinda like that Star Trek movie, the one with the Whales. When Dr. McCoy ask Mr. Spock what it was like to be dead and then come back to life. Mr. Spock's reply was, "Without a common frame of reference I would be speaking in gibberish."

I've yet to get into harmonics and RMS voltages. I think I touched a bit about kvar - Kilo Volt Amps Reactance. Maybe next time.

Posted by Thomas Allen Schmidt on Mar 4, 2009 01:08 am

#175 -  Renewable Energy > Technical Discussion: Other > Re: AC amps - DC amps
There is no "formula" for ac amps to dc amps.
If one had a load of 75 watts at 120 vdc the amps (.63) is identical to the amps for the same 75 watt load at 120 vac.
A clue is the "v" for voltage at the front of vdc and vac.

As for "isn't there a difference when dealing with the AC and DC and different voltages, watts, etc..."
No. But there are losses. Most of those losses end up as waste heat. While your system is running and charging batteries, feel the gen. head. Now the transformer and then the inverter. Chances are they will all feel good and warm depending on how long they have had current flowing through them.

I am curious about the gen. head. Is there no way to tap the gen. head for a full 120 volt circuit? "Weed" out the transformer.

As for "what is the formula to determine the maximum amount of amps being deliver into the battery bank?"

There probably is a formula but it would only be a "somewhere in the ballpark of" kind of figure because the efficiency's from one generator to the next can vary widely as well as transformers and battery chargers.

Chances are you may never see much more than 60 amps going into the batteries from that charger. Its not uncommon for manufactures to advertise higher ratings. Those advertised ratings probably came from some formula not a real world situation where KVAR might come into play literally lobbing off the peaks of the sinusoidal wave coming off you generator. Does your gen. head have a capacitor bank on it?


Posted by Thomas Allen Schmidt on Mar 3, 2009 06:25 am

#176 -  Renewable Energy > Technical Discussion: Other > Re: Need help with LED lighting
Thank you Mr.Clay

What we are wanting to do is, convert certain 400 watt metal halide pole top parking lot area lights by gutting the; ballast, capacitor, and mogul base lamp socket from the housing but keeping the reflector and clear glass lens then rebuilding it into a stand alone pole top PV/battery powered, LED counter part.

If its possible to "wire" 3 of the aforementioned LED's in series and then as many as 33, or maybe more, of those series strings in parallel, that would be 99, or more, of those LED lights.

The aim is to create an affordable retro-kit.
Those 400 watt replacement ballast kits with a new bulb can cost as much as $250.00 not including the labor to change it out. So you can figure what it would cost somebody to change them out say, 4 or more times.
Of course I don't how much longer a PV/LED change over would last. Need to build one and find out.

Posted by Thomas Allen Schmidt on Mar 2, 2009 02:03 pm

#177 -  Renewable Energy > Technical Discussion: Other > Need help with LED lighting
I have a smackerel of experience with electronics. None of it is "hands on" experience with LED's.

The following is a link to a PDF file with the specs. for a particular LED.

Is it possible to "wire" 3 or maybe 4 of these in series and then several of those series strings in parallel (maybe as many as 33) to work from a 12 vdc nominal battery bank recharged by photovoltaics?
The plan is to use as an outdoor night light off of the battery, so the higher "working" voltages from the PV array should not come into effect.
Thanks for any help.


Posted by Thomas Allen Schmidt on Mar 2, 2009 11:31 am

#178 -  Renewable Energy > RE General Discussion > Re: How to run a small DC motor??????
Oops, I overlooked the wire size.
At only .55 amps its hard to go wrong there.
To give you an idea. In household wiring, a 14 gauge copper wire is used on a 15 amp circuit. A 12 gauge copper wire is used on a 20 amp circuit. A 10 gauge copper wire is used on a 30 amp circuit. Chances are, if you have a 100 amp utility service to your home, its on a 2 gauge aluminum wire. Got any 18 gauge copper wire laying around?

These are maximum values in the chart at the site above. The values I gave for household wiring are dictated by the NEC or National Electric Code. Different types of wire and wire insulation will have different ratings.

Posted by Thomas Allen Schmidt on Mar 2, 2009 11:12 am

#179 -  Renewable Energy > RE General Discussion > Re: How to run a small DC motor??????
I can't know your knowledge of PV and electric motors and electronics so I'll try to keep it in simple terms and hope that I do not insult you. As much as it pains me not to just give you the links to what you will need to accomplish this task, I feel it would do you and everyone else here a great injustice. Afterall, "Give a man a fish and he eats for a day. Teach a man to fish and he eats for life."

There is no shortage of small PV modules that can produce 12 volts dc nominal at .55 amps. Here are just a few examples. Compare the specs. of nominal 10 watt PV modules.
.55 X 12 = 6.6

 A problem might occur though with the motor being able to withstand the higher "working" dc voltages of a PV module during high light levels as well as the lower dc voltage from a PV module during low light levels. The motor may over heat and melt down or if it can stand the higher or lower "working" dc voltages of a direct PV connection it may only run at full speed for an hour or two at noon time. This is were an LCB or Linear Current Booster would be used.

Check out the specs. on the "PPT 12/24 - 3"
They are a little high compared to your motor but I am sure someone makes them smaller.

More fun with electric dc motors.
My favorite is the "high voltage motor in 5 minutes."
Seconded by "12,000 volts from a rubber band and a soda can."

There is also no shortage of used PV yard lights at yard sale and such that may still have good PV cells in them. Just be mindful that you will need a multimeter maybe a soldering gun and stuff if you go this route. Remember; .55 X 12 = 6.6


Posted by Thomas Allen Schmidt on Mar 1, 2009 03:56 pm

#180 -  Renewable Energy > RE General Discussion > Re: What is energy?
Could what we have come to know as "gravity" be one and the same as what we know to be "molecular cohesion"?

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