I have (x3) 150W panels, and need 1600Wh a day. Suggestions for battery banks?

[Sunking]

If I were to touch the positive side of my battery terminal post with a metal wrench, and the floor has metallic strips which connect down to the chassis, and I'm standing on it, without rubber shoes, is there anything stopping the current from travelling through the metallic wrench, through me, and into the floor, to find the chassis, to complete the circuit?

You got the wrong picture. You do not need a wrench in your hand to have current to flow through you. All you have to do is just touch the battery terminal. Put one hand on the chassis, and touch the battery positive terminal with the other, and current will flow through you because you are now a complete circuit. But unless you are really hot, sweating like a pig, and sick you would never feel a thing. Even if you were hot, sweaty, and sick it would not produce enough current to hurt you or enough to make you jump. Just a little tingle.

Current is produced by applying a Voltage to Resistance. Current = Voltage / Resistance. You body resistance is fairly high on the order of thousands of Ohm's , and 12 volts is very low voltage. So if the body resistance is say 10,000 ohms then 12 volts / 10000 ohms = .0012 amps. Barely enough to have a sensation or feel it.

A wrench on the other had is extremely low resistance on the order of almost 0 Ohms. Contact resistance is higher then the wrench resistance. Let's say total resistance .02 Ohms. Then 12 volts / .02 Ohms = 600 amps which results in 7200 watts. At 7200 watts your wrench turns into vapor and liquid white hot metal. That you are going to feel and remember the rest of your life. You get burned not electrocuted.

Now if you climb an electric pole and touch a 13,200 volt lines, High current will flow through you and you burst into flames. But you would never feel a thing. That is what happened to these two fine copper thieves.

solar3.jpg

[Fractalcathedral]

A wrench on the other had is extremely low resistance on the order of almost 0 Ohms. Contact resistance is higher then the wrench resistance. Let's say total resistance .02 Ohms. Then 12 volts / .02 Ohms = 600 amps which results in 7200 watts. At 7200 watts your wrench turns into vapor and liquid white hot metal. That you are going to feel and remember the rest of your life. You get burned not electrocuted.

Thanks, that's certainly good to know. I'm starting to feel like buying a rubber mat and a set of insulated tools.

If you were to touch the top of the positive battery cable lugs with a wrench, after it is all connected and screwed in to the terminal post, would any amount of current transfer through the wrench instead of through the wire? Is the only thing preventing it that it already has a totally direct route back to the battery bank, and it's already a complete circuit and doesn't need to find an alternative path to ground/neutral? Or does current take all paths in inverse proportion to their resistance?

[Bala]

I know it's relatively low voltage, but my sister was electrocuted to death when I was young and the experience definitely instilled a healthy respect for electricity.

With all due respect, the questions you are asking tend to indicate this project may be out of your knowledge level and way to much to try and learn off an internet forum.

You got the wrong picture. You do not need a wrench in your hand to have current to flow through you. All you have to do is just touch the battery terminal. Put one hand on the chassis, and touch the battery positive terminal with the other, and current will flow through you because you are now a complete circuit. But unless you are really hot, sweating like a pig, and sick you would never feel a thing. Even if you were hot, sweaty, and sick it would not produce enough current to hurt you or enough to make you jump. Just a little tingle.


[ATTACH=CONFIG]6366[/ATTACH]

Trust me, from experience, living in the tropics where you sweat a lot and often have bare arms, touching a bare metal part of a car with a sweaty arm and touching the positive terminal with another sweaty arm will give you more than a little tingle, and that is just one car battery. lol!

[Fractalcathedral]

With all due respect, the questions you are asking tend to indicate this project may be out of your knowledge level and way to much to try and learn off an internet forum.

I have had a few weeks to piece together the entire picture, (from literally zero experience or education in electrical theory) and I feel I'm near close to understanding what I need to know to put a basic PV system together. (Or at least, the known-unknowns are dwindling, and there's enough redundancies in the information I'm getting that I feel the unknown-unknowns are probably being cornered as well into the "mathematics, esoterica, and deep and/or comprehensive understanding." category).

At first that meant selection of equipment, (knowing that there would be some feasible way to interconnect the components, when I got to that bridge), and now it means getting into the weeds of wiring and common stuff like "what bus bars are"; common ignorances that I have the pleasure of knocking down, one by one, every hour I'm looking into this stuff.

I am an autodidact by nature, and to learn efficiently you have to relentlessly attack your own ignorances by exposing them to light, placing every assumption to scrutiny. If you have a specific book that you'd recommend, or some bit of basic understanding that you think I'd benefit from, I'd appreciate the suggestion. I shed ignorance whenever it is revealed to me. But basic, general, "You may not be smart enough to do this." condenscension is less than helpful, pal.

[Bala]

[QUOTE=Fractalcathedral;148810 But basic, general, "You may not be smart enough to do this." condenscension is less than helpful, pal.[/QUOTE]

Not trying to be smart or put you down at all,

A 12V DC automotive circuit is simple compared to PV system where you have grounding bonding etc in both AC and DC, to learn this in a few weeks is a big ask and as with a lot of things we may think we have our head around it but have it wrong.

Some times we just need to know our limits and I believe electricity, A/C in particular, is one of them.

If I am not positive I know what Im doing then I dont touch it. I dont really care if I were to zap myself but with A/C it can liven a whole building and it may be someone else who finds that out.

That is to big a risk for me.

With mine I did all the DC and then had an electrician come and do the A/C, RCDs fitted etc.

Take care.

[J.P.M.]

I have had a few weeks to piece together the entire picture, (from literally zero experience or education in electrical theory) and I feel I'm near close to understanding what I need to know to put a basic PV system together. (Or at least, the known-unknowns are dwindling, and there's enough redundancies in the information I'm getting that I feel the unknown-unknowns are probably being cornered as well into the "mathematics, esoterica, and deep and/or comprehensive understanding." category).

At first that meant selection of equipment, (knowing that there would be some feasible way to interconnect the components, when I got to that bridge), and now it means getting into the weeds of wiring and common stuff like "what bus bars are"; common ignorances that I have the pleasure of knocking down, one by one, every hour I'm looking into this stuff.

I am an autodidact by nature, and to learn efficiently you have to relentlessly attack your own ignorances by exposing them to light, placing every assumption to scrutiny. If you have a specific book that you'd recommend, or some bit of basic understanding that you think I'd benefit from, I'd appreciate the suggestion. I shed ignorance whenever it is revealed to me. But basic, general, "You may not be smart enough to do this." condenscension is less than helpful, pal.

Having followed this thread for awhile, I've got to think Bala, first off, was not condescending, and more adult about it than a lot of others might be. Second, Bala was pretty much on the mark about your ignorance. As for reading, start with basic science, and then proceed to electricity and magnetism. Most folks need to crawl before they walk, and walk before they run. I've found there's more to knowledge than the bottom line.

Not everyone who tells you what you don't like is trying to hurt you or your feelings. I'm sure you're "smart enough", but it seems to me your attitude is abetting your ignorance. This is not nursery school, so autodidact yourself to the location of a good source on the basics.

[Fractalcathedral]

Not everyone who tells you what you don't like is trying to hurt you or your feelings. I'm sure you're "smart enough", but it seems to me your attitude is abetting your ignorance. This is not nursery school, so autodidact yourself to the location of a good source on the basics.

No, it just seemed like an attitude of "This is beyond your comprehension.", which is a statement drawn concretely, as if ones comprehension were a fixed sum and not a variable that grows by positive numbers everytime you sit down and study. So no, I don't think if I had all the components in front of me right now, I would feel fully qualified to install them. But I will, in time, and I will do it safely. You are absolutely right about the basics, I have actually been in the process of watching and taking notes on these electrical theory videos on Youtube before you said anything: https://www.youtube.com/watch?v=4DlQ...F66F5E60F09280

But it makes sense to work backwards from: "These components are compatible in a system." to "How electrical charge works", because it brings you to that middle area which involves understanding of both: "How the components literally fit together, in physical reality, and not on a diagram." So no, my attitude is fine, dude. It's a learning process. Electricity is complex, but it is drawn with clear causal lines and there is enough information out there, even if, you have to scrap it together from pieces.

[J.P.M.]

Have a nice life. I hope you find what you're looking for, but FWIW, for accurate and thorough technical information, utube is the idiots' unvetted and usually unverifiable bible.

[Fractalcathedral]

Have a nice life. I hope you find what you're looking for, but FWIW, for accurate and thorough technical information, utube is the idiots' unvetted and usually unverifiable bible.

Duly noted. That's why I try to corroborate all of this with other sources. These seemed pretty legit though.

I've asked this several times in this thread, and I'll ask it again. Do you have any recommendations about books or sources that cover these topics comprehensively, (without being decipherable only by untangling a baroque web of jargon)?

Alternately: Have I said anything in this thread that pointed to a specific deficiency in understanding, besides an understanding of the basics of electricity and magnetism? I am not being facetious, I would appreciate it. I'm sure you know more than I do on the subject.

[Fractalcathedral]

Not trying to be smart or put you down at all,

A 12V DC automotive circuit is simple compared to PV system where you have grounding bonding etc in both AC and DC, to learn this in a few weeks is a big ask and as with a lot of things we may think we have our head around it but have it wrong.

Some times we just need to know our limits and I believe electricity, A/C in particular, is one of them.

If I am not positive I know what Im doing then I dont touch it. I dont really care if I were to zap myself but with A/C it can liven a whole building and it may be someone else who finds that out.

That is to big a risk for me.

With mine I did all the DC and then had an electrician come and do the A/C, RCDs fitted etc.

Take care.

Oh, no problem. I understand. How big is your inverter?

[J.P.M.]

Duly noted. That's why I try to corroborate all of this with other sources. These seemed pretty legit though.

I've asked this several times in this thread, and I'll ask it again. Do you have any recommendations about books or sources that cover these topics comprehensively, (without being decipherable only by untangling a baroque web of jargon)?

Alternately: Have I said anything in this thread that pointed to a specific deficiency in understanding, besides an understanding of the basics of electricity and magnetism? I am not being facetious, I would appreciate it. I'm sure you know more than I do on the subject.

The short answer to your question as asked: No.

What part of "start with basic science" do you find confusing ?

As for what I know: Just like everyone else, I know several orders of magnitude less than 0.01% about anything, and probably less than most. But also, like everyone else, I have the means to acquire knowledge.

Comparing to an edifice: Knowledge, like a skyscraper, needs a good foundation.

Anything else along this line of thought is a waste of my time.

[Fractalcathedral]

What part of "start with basic science" do you finds confusing ?

Nothing at all. What part of "You are absolutely right I need to understand the basic science, and I am already looking into learning that, via Youtube / other internet sources, and since you basically generalized all the information on Youtube as junk, what alternative do you propose?" confuses you?

You are telling me to look for something. I respond: "Good point, I was already looking for it. Where do you suggest I try to find it?" and you say "DIDNT I TELL YOU TO LOOK FOR THAT THING WHAT PART OF THAT IS HARD TO UNDERSTAND?"

As for what I know: Just like everyone else, I know several orders of magnitude less than 0.01% about anything, and probably less than most. But also, like everyone else, I have the means to acquire knowledge.

Perhaps you ought to work on your reading comprehension skills first.

Anything else along this line of thought is a waste of my time.

Well at least we can certainly agree on that.

[Bala]

Oh, no problem. I understand. How big is your inverter?

My inverter is 3000w.

Before I did my DC for experience I had 30 years as a mechanic and 10 years of those working closely with electrical fitter mechanics, in both A/C and DC, single and 3 phase.

I have a fair knowledge base of A/C, enough to know that IMO you can not safely learn it off the internet or by reading books etc.

It may work but that does not mean it is safe it may provide power and seem good but when needed the RCD / safety devices or breakers may not work causing electrocution or fire.

[Fractalcathedral]

My inverter is 3000w.

Before I did my DC for experience I had 30 years as a mechanic and 10 years of those working closely with electrical fitter mechanics, in both A/C and DC, single and 3 phase.

I have a fair knowledge base of A/C, enough to know that IMO you can not safely learn it off the internet or by reading books etc.

It may work but that does not mean it is safe it may provide power and seem good but when needed the RCD / safety devices or breakers may not work causing electrocution or fire.

I have been focusing on the DC side of the equation, and referring to this:

It is a mobile Inverter and like any mobile Inverter does not need any AC protection. It does not generate enough power to operate a breaker. 600 watts dead bolt fault only generates a whopping 5 amps of current. A 14 AWG plug cord can handle 15 amps of current all day long and never break a sweat.

5 amps will kill you dead in a second, but breakers are not there to protect you, they are there to protect the wiring only from catching fire. What does protect you and the Inverter uses is a GFCI NEMA 5-15 socket to plug in your cords. Before you ask your next question NO GROUND REQUIRED SO DON'T EVEN ASK.

I only ever really need 600Watts for my inverter, but I am considering upping it to 1,000 Watts / 24vdc input from Cotek or Samlex, which according to Wholesalesolar rep is still technically probably a mobile inverter, although I doubt I'll ever need to push it above 300-400 watts at any one time.

I haven't ordered it, but when I do, its going to come with instructions about any necessary/recommended fusing and grounding. If I follow them to a tee, keep the manufacturer's phone number nearby for any questions, keep all cords safe from damage, I don't see why there should be any danger.

[Sunking]

To become a licensed electrician, and they are by no means all knowing of electrical takes a two year technical degree, and five years of documented experience under a Journeymen or Master Electrician before they are even allowed to take a test. That is just for a basic license. To become a Master or Journeymen takes an additional 5 years of documented experience before they quality to take the test. To keep the license in most states requires a minimum number of billable hours and 2 CE hours of education every year.
To be a professional licensed engineer (PE) takes a 4 year BSEE degree at an accredited university. A Fundamentals test is taken in the final year of school give you and EIT (Engineer In Training) certificate which is a comprehensive 8 hour grueling test on basic principles. From passing the EIT exam and successful completion of a BSEE degree program one must provide 5 years documented experience under another PE, letter of recommendation, before you are allowed to take the PE exam, a grueling 8 hour test as difficult as a Bar or Medical Exam. To keep you PE license current requires require a yearly minimum documented bailable hours and 2 hours of college credit.

Point here is it takes 7 to 10 years training/experience to be qualified to do electrical work, and a life time of study. There is no way you are going to learn a thing on You Tube or read in a book to learn what you need to know and how to do it. Those electricians and engineers coming out of school are GOFERS for the next 5 years learning how to not kill someone before they are trusted to work on their own.