the grid electricity flows through it from your power line and then any electricity that you don't use returns to the power line so it can continue to circulate through the grid. But, if you are not connected to the power grid but you have a photovoltaic or hydroelectric system, what happens to the electricity that you either do not use or do not store in batteries?
This may be a dumb question but if your house is on
- Thread starter NotMeantForTheCity
- Start date
Help Support Homesteading & Country Living Forum:
If they have solar panels and their batteries are full, and they do not use all the power coming off of the panels, the 'extra' power is just turned into heat and radiated into the air, just like how a black car gets really hot in the summer sun.
For a solarpower system to work great, you need a ton of batteries to store the power that would otherwise be wasted.
If you have a bunch of spare time, read thru:
https://www.homesteadingforum.org/threads/the-great-battery-thread.430/
Grid electricity is AC (alternating current). It flows first one way and then the other. In N. America it cycles back and forth 60 times per second. It is just electrons moving back and forth in the wires in your home and on the grid. If it is not being used he generators just produce less.
Electricity in batteries is DC (direct current). It flows from positive to negative. You need an inverter to change DC to AC. This is a question better served by a book rather than a post.
Electricity in batteries is DC (direct current). It flows from positive to negative. You need an inverter to change DC to AC. This is a question better served by a book rather than a post.
- Joined
- Sep 4, 2020
- Messages
- 9,521
For grid, only what you actually use "flows through" your house.
Although not 100% perfect in analogy, think about a city water connection. The only water that comes into your house is the water you use.
Solar is basically a "use it or lose it" proposition. You can use it to run things you want to run with electricity or you can store it in some kind of battery. Batteries are typically a finite place to store power and once full, they don't accept any more charge even if your panel are still able to pump out more electrons. Some people will use excess electricity to run something like an electric water heater mainly just to do ... something ... with that electricity. Occasionally, some might use that excess to pump water in some form or fashion (don't wanna complicate it).
Although not 100% perfect in analogy, think about a city water connection. The only water that comes into your house is the water you use.
Solar is basically a "use it or lose it" proposition. You can use it to run things you want to run with electricity or you can store it in some kind of battery. Batteries are typically a finite place to store power and once full, they don't accept any more charge even if your panel are still able to pump out more electrons. Some people will use excess electricity to run something like an electric water heater mainly just to do ... something ... with that electricity. Occasionally, some might use that excess to pump water in some form or fashion (don't wanna complicate it).
- Joined
- Dec 9, 2017
- Messages
- 4,097
The power company provides a voltage to your house. Nothing is "flowing" unless you apply a load across that voltage. Once a load is applied, current will flow. The higher the load, the more current flows. If there is no load, then no current flows.
The voltage you get from the power company (or photovoltaic cells or whatever) is called "potential energy". By itself, it is nothing really, except "potential" to make something happen. Apply a load across that potential and NOW you have current flowing and you are using energy. And the power company will bill you for that. If you could reduce your load to zero - unplug everything, disconnect everything, get rid of all parasitic loads, then you would not be using any energy. And the power company would not bill you (except maybe for a "connection fee" or some other minimum amount that they always charge you for, regardless if you are actually using it or not).
Think of it kind of like this: You "pull" energy from the power company (by applying a load), the power company does not "push" energy at you.
The voltage you get from the power company (or photovoltaic cells or whatever) is called "potential energy". By itself, it is nothing really, except "potential" to make something happen. Apply a load across that potential and NOW you have current flowing and you are using energy. And the power company will bill you for that. If you could reduce your load to zero - unplug everything, disconnect everything, get rid of all parasitic loads, then you would not be using any energy. And the power company would not bill you (except maybe for a "connection fee" or some other minimum amount that they always charge you for, regardless if you are actually using it or not).
Think of it kind of like this: You "pull" energy from the power company (by applying a load), the power company does not "push" energy at you.
I've heard of using solar to pump water into a storage tower and then using that water to run a hydroelectric set up at night. But, the water tower wouldn't be any different than a battery.
Problem is that you will always lose energy on the production of energy.
“Energy cannot be created or destroyed; it can only be changed from one form to another.” (Albert Einstein).
“Energy cannot be created or destroyed; it can only be changed from one form to another.” (Albert Einstein).
Utilities sometimes do that. I am familiar with a hydroelectric dam that used to do that, not sure if they still do. When they had excess power, they'd pump water into a large man-made lake, as in many thousands of acres. Then when demand was high, they could tap into that as an additional source of water for hydroelectric power production.
I really do not think that's all that practical on a small scale, not really sure how practical it is on a large scale. I suspect that there is a lot of wasted energy in moving water.
The short version is, if you want more storage, get more batteries, of whatever flavor floats your boat, learn to take care of them, and enjoy.
City of Chattanooga, TN. Does just that. Pump water to a man made lake on a ridge overlooking the city at night while utility rates are minimal. Bring it down the next day during peak needs at much higher rates. Must work out,, they've been doing it for years
I posted about that one before, looked for it but I couldn't find it
.They used excess solar power to pump water up to the lake during the day, and when the sun went down, the water in the lake powered the city at night.
It worked great.
Last edited:
In that case, the energy saved/used is nearly the same. You are just paying less $ because of the nighttime low energy costs.They used excess solar power to pump water up to the lake during the day, and when the sun went down, the water in the lake powered the city at night.
It worked great.
A perpetual energy device is impossible according to Einstein.
Solar energy shouldn't create an excess problem, it just won't be there when the sun goes down.
- Joined
- May 29, 2020
- Messages
- 5,034
This dam at the southernmost end of the Colorado river is used to control down river flow and provide demand electricity.
https://usbr.gov/projects/index.php?id=328
Solar panels without battery back up is simply having the home owner install capacity for the utility, it provides no back up power for the home owner. However, that is beginning to change, many are starting to include in-house battery storage and inverter capacity to provide some power backup in an emergency.
https://usbr.gov/projects/index.php?id=328
Solar panels without battery back up is simply having the home owner install capacity for the utility, it provides no back up power for the home owner. However, that is beginning to change, many are starting to include in-house battery storage and inverter capacity to provide some power backup in an emergency.
Solar panels should be sized for the homeowners peak usage. Electric Utility would only receive the surplus.
The local government entity I "volunteer" at installed solar (no battery). After two years of operation the payback went from the forecasted 10 years to 8 years. Now they are planing to extend solar to their plant.
Grid tie makes a nice "reserve" from which to add to or withdraw from. If you have extra, it can go into the grid and your meter "runs backwards". If you don't have quite enough, you can draw on what you produce and make up the difference from the grid.
But if you're off grid, getting things balanced is a challenge. If you have just enough to do what you need to do on a sunny day, then you're gonna be short on a cloudy day. If you size it so you have what you need on a cloudy day, then you'll be way overproducing on a sunny day. And it's pretty much a "use it or lose it" proposition with batteries being the most common form of storing energy for later. Batteries are limited, though, in that on a sunny day, you may use all you want, completely charge your batteries, pump all the water you need, and still have excess electrons with nowhere to go. If you cut back on the production side of it, then you have more days when you're short of electrons and have to either go without or make them up in some other way. Now, if every day were exactly the same, it gets a lot less complicated. Few of us have that kind of location, though.
Fun, isn't it?
Most of our homestead if on grid. But part of it is far enough from the electric lines that it's not practical to have grid power there. So in those places, I do use a bit of solar to provide for some basic needs. One of my goals is to expand that off grid footprint and encroach on some of the grid tied space. My big greenhouse is 100% solar and I want to expand that a bit. My small greenhouse is 100% grid and I'd like to move at least part of that over to solar. I'd like to add the capacity to run a couple of deep freezers strictly off of solar. And at that point, I'm approaching a minimal backup system that could keep the house going, minimally.
I have no inclination to go 100% solar. But I really do like the idea of having power available, even limited, without having to fire up a generator. (I have two of those already.) Also, as long as I am hooked to the grid and use some electricity, I feel like I'm in more of a "gray man" situation. "Nothing to see here."
But if you're off grid, getting things balanced is a challenge. If you have just enough to do what you need to do on a sunny day, then you're gonna be short on a cloudy day. If you size it so you have what you need on a cloudy day, then you'll be way overproducing on a sunny day. And it's pretty much a "use it or lose it" proposition with batteries being the most common form of storing energy for later. Batteries are limited, though, in that on a sunny day, you may use all you want, completely charge your batteries, pump all the water you need, and still have excess electrons with nowhere to go. If you cut back on the production side of it, then you have more days when you're short of electrons and have to either go without or make them up in some other way. Now, if every day were exactly the same, it gets a lot less complicated. Few of us have that kind of location, though.
Fun, isn't it?
Most of our homestead if on grid. But part of it is far enough from the electric lines that it's not practical to have grid power there. So in those places, I do use a bit of solar to provide for some basic needs. One of my goals is to expand that off grid footprint and encroach on some of the grid tied space. My big greenhouse is 100% solar and I want to expand that a bit. My small greenhouse is 100% grid and I'd like to move at least part of that over to solar. I'd like to add the capacity to run a couple of deep freezers strictly off of solar. And at that point, I'm approaching a minimal backup system that could keep the house going, minimally.
I have no inclination to go 100% solar. But I really do like the idea of having power available, even limited, without having to fire up a generator. (I have two of those already.) Also, as long as I am hooked to the grid and use some electricity, I feel like I'm in more of a "gray man" situation. "Nothing to see here."
- Joined
- May 18, 2023
- Messages
- 12
So in my introduction post, SoJer brought this up:
Another really good way to tell the quality of a panel by the datasheet is by its temperature coefficient of Voc. People very radically underestimate the effects of temperature on solar power production, and the temp co is how you determine the extent to which a panel is effected by it. The higher the temp co (sometimes expressed at TkVoc or TcVoc) the worse the panel will perform, generally, in relation to its nameplate wattage. A TcVoc of -0.27 is good. Technically some of the Canadian solars on this list are right around there- they're pretty good mods on paper, they just have a tendency to delaminate. A TcVoc of more that -0.34 is getting bad. You'll see some of these are something like -0.44. yeesh.
To address the second issue of what to look for, be carefull to look around the edges of the frame on the front. That's where delamination starts. Any discoloration, as from the glass separating from the wafers underneath, don't buy it. Visible cracks in the glass are less of a big deal, but obviously to be avoided, basically because wind stresses on cracked glass can cause that same delam if you're not careful.
So I'll start by answering that (in partial), and use this thread to answer any other questions folks might have about solar, since it's kinda my thing. And I'll read through the thread here up till now and address anything I could potentially help with shortly. @SoJer , when it comes to used panels, the brand matters a bit, yeah, but the condition matters more. Per that list, I don't see any that are great at a glance. I'd call most of these bottom of the mid-tier, or bottom tier. To address the former, you want to look at what's called the linear power curve: most brands post it on their datasheet, which is the first place to look. You can determine the lifespan of a panel to some approximation by looking at that linear power curve. If it's a panel (like some on this list) that shows you loosing 15% over 10 years and their corresponding linear power warranty is only ten years, that's low-tier. If it's more like a 10% loss over a 12 year period- that's a higher quality panel, generally. LGs (they stopped making them now), Sunpower, REC, and panasonic are probably the best- Qcell and below (they're made by HANWA) now you're into the middle tier. Jinko, Trina, Yingly and the like are at the bottom. Also, pay attention to the nameplate wattage. Things that were manufactured back in the days of 200-220 watt panels were wildly less efficient and didn't last as long. You want to look for the higher nameplate wattage 60 cell panels- 300 and above if you can find them. And that 60 cell bit is important. Lots of 72 cell mods are great, but they're a bear to haul up on a ladder if you're a DIY installer- typically you want a laddervator or manlift to build an array of anything 72cell or 144cell. 120cell are the same size as 60, and they work a little better, but you probably won't find any used.Bienveneetoes from SW AZ.. (SO glad it ain't 'from Lost Angeles', anymore!
Keen to know (and, 'not here' / some Other thread, is fine - this is just to 'seed further discussion') your thoughts on "Used" / blem 'Commercial-grade' Panels, ie: https://www.santansolar.com/product-category/solar-panels/used-solar-panels/
..We've not used them (specifically) yet, but Do have friends that say they've (specifically) been Great.. Interested in feedback on 'Which Brands, therein' are good / bad / ugly, etc.. Again, we can start another thread / chat yonder, about it, just tossing a horseshoe out into the ring to get started.
Cheers and again, Welcome to the Fam.
jd
Another really good way to tell the quality of a panel by the datasheet is by its temperature coefficient of Voc. People very radically underestimate the effects of temperature on solar power production, and the temp co is how you determine the extent to which a panel is effected by it. The higher the temp co (sometimes expressed at TkVoc or TcVoc) the worse the panel will perform, generally, in relation to its nameplate wattage. A TcVoc of -0.27 is good. Technically some of the Canadian solars on this list are right around there- they're pretty good mods on paper, they just have a tendency to delaminate. A TcVoc of more that -0.34 is getting bad. You'll see some of these are something like -0.44. yeesh.
To address the second issue of what to look for, be carefull to look around the edges of the frame on the front. That's where delamination starts. Any discoloration, as from the glass separating from the wafers underneath, don't buy it. Visible cracks in the glass are less of a big deal, but obviously to be avoided, basically because wind stresses on cracked glass can cause that same delam if you're not careful.
Here's what I did:
Rented 4 industrial solar panels.
figured out how long it took to charge a single battery.
figured out how long said battery would run EVERYTHING in my camper.
Multiply by 15. 4 deep cycle truck batteries did just fine but all I had was a light, a fridge, a fan and a laptop, I was even able to run a space heater until a bit after dark, then I went to natural gas. Normally I had enough juice to still run the light in the morning.
Yup, converter too. it came with the Winnebago.
Alligator clips and splice clamps are my friends!
Alligator clips and splice clamps are my friends!
- Joined
- May 18, 2023
- Messages
- 12
oh good. I've seen people boil off and burn batteries that way before- just plugging a 30 or 40 volt panel straight onto a 12v battery. The things people get up to!
Tell me about it! a straight connection has been known to blow deep cell batteries up like a bomb! hydrogen gas+spark= battery acid bath and acid-coated shrapnel! I saw a doofus try to recharge a car battery with an extension cord once! fortunately, the acid was weak, and his eyes still work!
