Hello everyone and welcome to the series. We’re going to talk about how to power your home or house from solar power. We are going to take a deep dive into residential solar power, so you’ll know exactly what you need before calling solar company. Deciding whether you want an on-grid system, an off-grid system, the types of solar panels, and whether to have a charge controller or a grid tie inverter, or micro-inverters is important.
We’ll talk about battery bank solar panels, the cost involved, whether or not it’s all worth it.
Plus, the complications of getting residential solar power installed. Since I live in South Africa and you probably live in the states, you’re about to see why life for you is 1000x easier to get started with solar power then it is for folks in my Country.
Understanding the Difference Between Living Off The Grid vs. Living On The Grid With Solar Power.
A basic understanding of on-grid versus off-grid is important, but before I walk you through this little picture and discuss on-grid versus off-grid and what the grid is, let me show you some of the solar equipment in my home, so you are familiar with what I’m talking about when I show you this diagram, and then we’ll get down and explain it.
Let’s start off by looking at these solar panels. We are going to talk about these in detail later on, and I might even refer you to some other videos that I’ve made where I talk about the performance of the different types of solar panels, and the different conditions. The one thing to note, that today you can get cheaper panels from China and what have you, but you want to be aware that, if you do want to use your panels with high voltage systems, which is something we’ll talk about, you have to consider the build quality and how they’re put together. That’s something we’ll talk about in terms of the gaps with the connectors. We’re also going to talk about monocrystalline versus polycrystalline and amorphous, and which seem to perform better under what conditions.
This is an MPPT charge controller. It’s a maximum power point tracking charge controller, and this device is something I’ll point out, which is especially useful in off-grid systems, as it takes the power from the solar panels, it converts it, it does a DC to DC conversion so that it’s at the right voltage for your battery bank, to charge a set of batteries. This can’t supply power directly to your house, and that’s why this particular unit is more useful in off-grid systems, but we’ll have a look at that when we come to the actual diagram itself.
Here we have the grid tie inverter. This takes the solar power directly from the solar panels and converts it to your main’s electricity to feed your house directly, or even to feed back onto the grid. This unit here is the grid tie inverter, and this is a normal inverter. This doesn’t take power directly from the solar panels, per se. It can be fed from this, can pick up energy from the grid tie, and it can use it, but this is used to take power from a battery bank and convert that to AC power to power your house. It can also charge the actual battery bank itself.
I’ll just show you, down here I’ve got a large bank of Lead Crystal batteries. I’ve been doing research into different battery technology to find what is best, and I’ve decided to go with a bank of Lead Crystal batteries. These are the components, again, that I’ll be talking about in that diagram today, so we get an understanding of how they’re all hooked together. Here we have an energy monitor. The one reason I bring up the energy monitor is that, one of the important things to understand when you are going to, or considering adding solar power to your house, you need to understand … You need to scope and size the requirement of your energy source. To do that, you need to understand how much energy you’re using.
You can, of course, have a look at your monthly bill, but ultimately, what we want to do in this series is was, have a look at the different monitoring equipment to either measure your household power, or the individual power requirements for each of your appliances. I’ll be going through the ways that you can do that with the different types of monitors and measuring equipment.
The other thing that we’ll also be talking about in the system, particularly when it comes to understanding the solar energy in the South African context, is the pre-paid meter, the different type energy meters that your power company can provide you with, and the potential challenges that they can pose. This is obviously the power company energy meter. This is a battery monitor.
A lot of this equipment, what I will do for the more advanced people is, I’m going to go to into individual tutorials on how these work, and how you can configure them, because these have lots of configuration parameters to make them work properly so that you can monitor your installation correctly. One of the other things we will be talking about is how to make your house run more efficiently, because the more efficient you make your house run, the less power you need from your solar system, which is potentially going to be expensive. Here, what I’ve done in our house, is that our kitchen, we used to have a set of big fluorescent tubers, which chew up a lot of energy, and these are LED tubes.
These only use a third of the power that a normal set of fluorescent tubes use, but there are some downsides that you need to be considered with LED lighting of this kind. I have other LED lighting in my house, and I’ll walk you through that, and try and show you when LED lighting is appropriate or not, and also CFL lighting as well. We’ll also then have a look at different monitoring software to understand how are your solar arrays actually performing. I monitor my solar array, just because I’m intrigued to understand what daily power I’m getting from my solar array. Out of interest, I’ve got a 2,250 watt array on the roof.
At the moment, at the beginning of spring, if I have a full day of sun, I’ll get about 12.8 kilowatt hours out of that array.On a bad day, yesterday we had a day when it was overcast and raining, I still managed to get about 6.8 kilowatt hours out of it. This is something which, to understand, how are your system is going to perform at different times of the year. Again, this assists you with sizing your array to cater for whether you want to actually generate money from your system, or just power your house, and to understand, can you power your house under cloudy conditions, and how will it perform under winter.
Let’s get down and have a look at the first set of basic things to understand, and that is an on-grid system versus off-grid system.
solar panel iconLet’s have a look at a typical on-grid system and the components, and potentially how they all hang together. First of all, when we talk about on-grid, we’re talking, the grid would be your electrical power company, or in the case of South Africa, we would say Eskom, because we have a national power company. There is no competition, it’s just one supplier. The grid feed, basically, is the electricity feed which comes into your house as AC power, and that can be, in the States, it’ll be 110 volts, or in South Africa it’s 220, or in the UK it’s 240. That is your main grid feed into your house. To get solar power onto your grid-connected house, you could then have a solar panel, which is installed on your roof or on your property somewhere. It can then feed a grid tie inverter. Now remember, I pointed out that grid tie inverter. What that grid tie inverter does, it takes the direct current, or DC power, that comes from your solar panel, and it directly converts it to AC power, which can directly power your house.
This is probably one of the cheapest and most efficient ways of having a system power your … Or using solar power to power your house. The other option is to use, as I pointed out, that MPPT charge controller. You could have that these dotted lines I’ve got going to a, what I’ve noted here, is a Flexmax, which is the model of the charge controller I have. It could feed a charge controller which then charges a bank of batteries. That bank of batteries would then have to go through a separate big inverter, which if you remember, I also pointed out, and that would then convert that to AC power to power your house.
Now, what’s the problem with this system? For one, every time you go through a device like an inverter, or through a set of batteries, you’re going to have losses which are going to make your system more inefficient. In this case, if you didn’t have the grid tie inverter, and you went through your charger controller, you’d be going through there. You would have losses over here. You’re then putting power into a battery which has resistance and losses when you put it in. It then has to come out of that battery, there are losses. Through another inverter, there are losses, before it goes into and feeds your house. These systems, in terms of using batteries, for the most part, if you don’t need to, you don’t want to use batteries because they cost a lot of money, you’re going to have to replace them every couple of …
Every three to five years, unless you buy a really expensive bank of batteries which can last 15 to 20 years. You want batteries if you want to cater for a power outage from the grid, so if the grid fails, then you have a backup source to power your house when there’s no grid. In South Africa, we have an aging grid network which hasn’t been maintained, so that’s one reason why I installed a bank of batteries, to cover for outages. Also, because at this point in time, because I cannot feed back onto the grid, I want to make the most use out of the solar power which is installed on my house. Our household, during the day, probably uses, ticks along on average at about 800 to 1000 watts, but I’ve got 2200 watts installed on our roof.
That can be handy because on a cloudy day, even if there’s a drop in the power off the roof, I can still run my house, but I’m then losing, on this bright sunny day, I’m losing the potential of all that power, because I cannot feed it back to the grid and gain credit for it. What I do is I charge … I go through a grid tie inverter which is far more efficient than going through a charge controller. That directly goes through the grid tie inverter and feeds my house. Any excess power is then pulled through the bigger inverter and charges the bank of batteries. That means at night time, I can then use the excess power which I’ve stored up in the batteries, and feed that back into the house at night, so that I’m not using the grid.
Again, when the morning comes, I then use that excess power to recharge the battery bank. But as I said, that’s expensive. You can get away and reduce the cost of your system by literally just having a big bank of solar powers and a grid tie inverter. For the most part, in the States and Europe, those are the type of systems that they use.I’m refer you to a link of one of my viewers called Matt. He’s just installed a 5.2 kilowatt array on his house, and it’s a wonderful production. He does some aerial photography, and if you’re interested, do go and have a look, because it really is a nice installation. What I want to point out is, Matt makes use of another technology which is quite interesting. You can see I’ve got a note here about microinverters. What you can do, I have one grid tie inverter for a whole bank of 9 solar panels. Those solar panels have to be carefully connected so that they push the power through to the grid inverter in the most efficient way, so that you maximize the power coming off them.
They are connected in series, so that means if any one of those panels is shaded, or is not optimally pointed to the sun, it can draw down the power of the whole bank of solar panels. That is something you have to be careful with with installation, and something I have to live with because, for one, we don’t, here in South Africa, have a big market of microinverters, but on Matt’s installation, you can have, he has one small inverter per solar panel. That means you get the maximum efficiency from each and every solar panel, and if you have a problem with either one solar panel, or in fact, if you have a failure on my system of the single grid tie, everything goes down.
If you have a microinverter on each and every solar panel, you can still have a failure and have the rest of your array up and working, but just the one solar panel or inverter will be down. Let’s just talk about feeding back onto the grid. In an ideal situation, what you want to do with your excess power, as opposed to trying to pump it into a battery bank, you would want to feed it back to the grid so that you can gain credit, or even earn money back from your power company for doing that. For the most part, in Australia, in Europe, and the US, you can do that.Here in South Africa, unfortunately we’re a bit behind the times. We are playing catch up. It’s about to happen. They’re about to bring in this thing called net metering, which is what you do is they meter to understand what you use, and what you feed back.
home iconIn some cases, no money exchanges hands. You just gain credit for what you push back, and then at night, for instance, you pull back off the grid and you use that credit that you had. The best way to look at that is to try and understand how that’ll work over a year, because obviously you have to account for winter, and you may generate a lot more power in summer, and then be pulling back more during the winter months, and so you need to try and size your array appropriately if that’s what you want to do. In South Africa we have these prepaid meters, so at the moment, we have to have an intelligent system that disconnects the grid when I have excess power, so it doesn’t feed back, and that I use it internally in the house.
What we can go into is a discussion on how to intelligently use that power, whether it’s pushing into battery bank, or intelligent load diversion. By load diversion, I mean switching your load to either heat up your water heater with the excess power, or switch on your pool pump when you’ve got the excess power so that you don’t waste any of your excess energy from your solar panel. Let’s now have a look at an off-the-grid system. Certainly, in South Africa, this is probably, at this point in time, one of the areas where people are willing to spend money on photovoltaic power. Generally speaking, if you have a farm or a holiday cottage which is off the beaten track in the mountains, and it’s going to cost a lot of money to bring the grid to your house, it’s far more cost efficient to then bring in a system, a solar power system, which can solar power your house independently.In the on-grid system, one does want to be careful and calculate. If you really want to power your house as much as you can, you need to carefully calculate what your power requirement is, but sometimes it’s not that critical if you’re going to have the grid connected, because you can always get power off the grid.
That’s why it’s far cheaper to make your house run more efficiently than have to spend the extra money in three extra places to provide the power for your house.An off-the-grid system, one can potentially up-rate far more efficiently. For most grid-connected systems, you have to cater for appliances that are running at 220 volts or mains, and as I said, each time you start going through a charge controller or batteries or an inverter, you start losing efficiency. In an off-the-grid system, in an ideal world, what you’d want to do is have your solar panel bring in your power, you go through your charge controller, which you need to do because you need to control the amount of charge which goes into your battery bank. An MPPT charge controller makes the collection of power off your solar panel far more efficient. I have a video which explains MPPT, which I’ll link to over here, but once you’ve got the power coming into your battery, you potentially have the option in an off-the-grid system to try and run as much of the household off, let’s say, a 12 or 24 volt, or 48 volt system.
For instance, if you have a 12 volt system, you could potentially power your down lighters and lighting directly from that 12 volt. It means there’s no inverting, it means it’s a far more efficient use of the power coming from your power source of the battery bank. Of course, you may have to introduce an inverter, as I’ve got here, so that you might be able to partially run some things off 12 volt, but then you obviously might have some appliances or entertainment systems which need mains voltage, either 110 or 220, and then you’ll take those through an inverter and into your house. That’s an off-the-grid system where you don’t have the grid feeding your house.I dearly hope that kind of gives a good start, or introduction into solar power, and in terms of showing some of the different components, and off-grid versus on-grid. There’s lots more to discuss.
A lot of the questions which have been posed to me so far, particularly for the South African market is, is it financially viable going this route at the moment? What I plan to do, is I’m try and do some calculations to show what systems could potentially be viable at the moment in South Africa. The one thing for me that is quite important is, at the moment, people need to realize that over the last four years, since 2008, our electricity prices have probably doubled. They are going to double again within the next three to five years. We also have the issue that not enough money has been invested on our power grid. I think potentially, the same might be, from what I hear, the States might even suffer from the same problem. They have an aging grid as well. If you do have those issues, then potentially, you’re going to have more power outages, and then the financial viability might seriously be outweighed by inconvenience, if you don’t have electricity.
In South Africa we’ve got a tiered system for what you pay for your electricity. If you use less electricity, the number of kilowatt hours you use per month become cheaper. As you step up and start using above more than 150 kilowatt hours, which of course, most families would be using more like 600 to 1000 kilowatt hours plus, once you start bringing your kilowatt usage below those certain thresholds, you start paying a lot less per kilowatt hour. My goal for my system was to get below 600 kilowatt hours. I was easily using 1000 kilowatt hours, 800 to 1000 kilowatt hours, and if I bring mine below 600 kilowatt hours, I suddenly save a lot more money. We’re going to go into a discussion about that. We also potentially, where it becomes … more viable, particularly for folks in Europe and the States is that you get rebates for your systems. In South Africa, we don’t.
As I said, please do pose your questions. We’re going to cover things like power factor. Someone raised a very interesting point about power factor. Normally, power factor is something you don’t have to worry about in a private residence because power factor isn’t measured by your metering system, and if you have a bad power factor in your house, it is the electricity company that takes the knock. That’s different for big industry. However, if you’re generating your own power, does power factor play a part, and potentially it does. That’s something we’ll investigate.
Let’s say, start posting comments about the questions that you might have and would like to see answered, and I’ll certainly be going into far more detail on all the individual components to show what part they play, and the different options and pros and cons of each of them.