Going Green With Solar Electrical Energy - Step Three, to Contract Or DIY?
You just can't put enough information into a single article to explain the processes of going green with solar electrical energy, so we broke it into three steps.
In the first article "Step One, Determining your Current Use" we looked at how to determine how much energy you use at present and how to lower your consumption.
In he second article "Step Two, Choose Your Technology" we looked at the types of systems in use and the equipment needed to use them.
In this article: "Step Three, to Contract or DIY?" we will look at what it takes to install the various types and whether you should do it yourself.
Now that you know more about your energy needs and the technology available, you may be asking yourself, "Is this something I can do myself? Depending on your existing experience and dedication to learn new things, it might be worth tackling yourself.
If you don't, at least you know better what to look out for when looking for a contractor for your project.
As you might imagine from our previous article, it is going to be difficult to make a full DIY project if you want to install a grid-intertie system.
This is primarily because of the potentially hazardous high voltages involved.
I'm not even certain you can buy a grid-intertie inverter without some sort of credentials like being a licensed electrical contractor, because they just won't work in an off-line system and there are so many possible problems that could be caused by an incorrect installation, they might be in "liability avoidance mode" now and for some time to come for grid intertie systems.
In addition, if you're thinking about using the new flexible cells, you will probably not be able to participate except as a helper, because the manufacturers of these systems are still requiring their trained installers to put them on the roof panels.
I think this is primarily due to warranty requirements.
There are a few manufacturers that will sell roof sections with the flexible cells installed, but these are fair bit higher in cost due to the shipping requirements of the panels unless you are near their factory.
With most situations, the roof panels come from a local factory where rolls of metal are folded into roof panels and cut to size, and the PV cells are shipped in from their manufacturer.
Thus, you don't have to pay the higher shipping cost of pre-assembled panels.
Depending on your local situation, and whether you've done any electrical wiring in the past, you might be able to work as a sub-contractor to the official "contractor of record" to do most of the heavy work.
I've seen projects where the homeowner installed the cells and made the interconnects between cells, and the contractor came on site, inspected and approved the interconnects, then made the final connections to the inverter and grid himself.
In this manner, you may legally be able to participate in the process and get a healthy discount of the total price.
If you are in a remote area or planning an off-grid system, you may be able to do it all yourself, especially if you are in a state or locality that allows you, the homeowner to act as your own electrical contractor.
I know there are a lot of places out there where it is legal for you to do your own work and the (usually county or municipal) inspection officials will deal with you directly, and for those of you in these areas, it's mostly an issue of whether you have or can learn the requisite skills.
So What skills are required to install panels For regular PV panels, you need to handle a lot of rectangular panels about 36 inches wide, 60 inches long, up to 2 inches thick and weighing around 55 pounds each.
Bear in mind that you need to mount these at an average angle towards the sun for your location, so that means installing a rack first.
For many people, the only place with sufficient space that is clear for sunlight is on the roof, so that adds to the complexity and danger.
Once you have the individual panels in their racks, you can do the interconnections.
Bear in mind that any time there is light falling on the panel, it is producing some power, so these connections are essentially hot any time you can see well enough to make the connection.
Each panel will have to be connected to the charge controller though a series diode that keeps from discharging the batteries through the cells when they are at a lower voltage than the battery, unless the charge controller has one built in for each panel connection.
If your charge controller doesn't have individual connections for each panel, you will need the series protection diodes anyway.
Your charge controller will connect to your battery bank.
The wiring between the panels and charge controller should be large enough gauge to prevent excessive voltage drop, or you will be wasting some of your precious energy by heating up the wire instead of charging the battery bank.
The battery bank should be in a well ventilated room separate from your home, and have a direct vent to the outside.
It should be well insulated so the batteries are not exposed to excessive heat in the summer or freezing temperatures in the winter.
There should be sufficient space that you can work around the batteries safely, and remove and replace any single battery without crowding or bumping into the others.
You will need to store some maintenance equipment as well, and most people keep it in their battery room.
The distance from the panels to the battery room should be as short as reasonably possible, as the longer you have to run to get to your panels, the larger gauge the wire will need to be to prevent excessive voltage drop.
It really doesn't matter as much how far it is from your inverter to the home, as AC power loss isn't nearly as great as DC over longer wires.
Plan on having your inverter in the same place as your batteries so the connection to the batteries is very short.
You may be pulling some heavy current at times from the battery bank, and this connection is the most critical as relates to wire size.
The best layout I've seen is a small building with a battery room and and immediately adjacent room for the charge controller and inverter.
This way, the charge controller and inverter aren't exposed to the possibly corrosive gasses generated by the batteries during their charge/discharge cycle.
Connection to the home should be through an approved disconnect or transfer switch that feeds the main power panel.
At this point, I should bring up another possibility, that of having an "off grid" system connected to a house that is also on the grid.
In this sort of system, your solar system is not connected to the home at all during much of its life, but when you have enough power in the batteries and/or a nice day with plenty of sunshine, you can throw the transfer switch over to the solar system and run on it.
If you don't have enough power or capacity for a large current draw (perhaps you need to run the washing machine and your system or inverter isn't big enough for it) you can throw the transfer switch over to the main grid connection.
This is very similar to the way a standby generator is connected to a home that is on-grid in a location that experiences enough power outages to make it worthwhile for the additional cost of the generator and transfer switch.
Another quick note about generators.
If you are in a remote area and have an off-grid system, you'll probably want to have a generator available as well.
This can be used in either of two ways.
One is to use it only to charge the batteries when they are low, and another is to connect to the house in place of the solar system when you have higher needs or the solar system batteries are low.
The main difference is the size of the generator.
I know people that have a relatively small (1000 to 3000 watt) generator that they use only to charge the batteries when the panels are not producing enough or the batteries are low.
The use here is relatively low fuel consumption over a greater amount of time to keep the batteries topped off.
The other method, and I also know people that use this one, is to connect the generator to a transfer switch and take the entire home load on the generator.
This requires a larger, more fuel hungry generator, but can result in lower run times.
If you do go for a larger generator, consider a low-rpm diesel.
They tend to be better on fuel and because they run at lower rpm they last a lot longer.
The net running cost of either approach seems to be about the same, given similar energy demands as near as I can tell from the anecdotal evidence presented by the individuals that will talk about their systems.
Generally speaking if their system is doing what they want, you can't shut them up, and if it's not performing up to their expectations, you can't get a word out of them unless they're seeking advice.
Sounds like pretty normal human behavior to me.
As you can see, there's quite a lot that needs to be done to get an effective and economical solar electric system in place and working properly.
In many instances, this is within the capabilities of a careful and dedicated DIY-er.
If this fits your description, great, but be sure to get more detailed instructions and plans before you take on even the smallest of projects of this type, as you are dealing with potentially lethal voltages if something goes awry.
In the first article "Step One, Determining your Current Use" we looked at how to determine how much energy you use at present and how to lower your consumption.
In he second article "Step Two, Choose Your Technology" we looked at the types of systems in use and the equipment needed to use them.
In this article: "Step Three, to Contract or DIY?" we will look at what it takes to install the various types and whether you should do it yourself.
Now that you know more about your energy needs and the technology available, you may be asking yourself, "Is this something I can do myself? Depending on your existing experience and dedication to learn new things, it might be worth tackling yourself.
If you don't, at least you know better what to look out for when looking for a contractor for your project.
As you might imagine from our previous article, it is going to be difficult to make a full DIY project if you want to install a grid-intertie system.
This is primarily because of the potentially hazardous high voltages involved.
I'm not even certain you can buy a grid-intertie inverter without some sort of credentials like being a licensed electrical contractor, because they just won't work in an off-line system and there are so many possible problems that could be caused by an incorrect installation, they might be in "liability avoidance mode" now and for some time to come for grid intertie systems.
In addition, if you're thinking about using the new flexible cells, you will probably not be able to participate except as a helper, because the manufacturers of these systems are still requiring their trained installers to put them on the roof panels.
I think this is primarily due to warranty requirements.
There are a few manufacturers that will sell roof sections with the flexible cells installed, but these are fair bit higher in cost due to the shipping requirements of the panels unless you are near their factory.
With most situations, the roof panels come from a local factory where rolls of metal are folded into roof panels and cut to size, and the PV cells are shipped in from their manufacturer.
Thus, you don't have to pay the higher shipping cost of pre-assembled panels.
Depending on your local situation, and whether you've done any electrical wiring in the past, you might be able to work as a sub-contractor to the official "contractor of record" to do most of the heavy work.
I've seen projects where the homeowner installed the cells and made the interconnects between cells, and the contractor came on site, inspected and approved the interconnects, then made the final connections to the inverter and grid himself.
In this manner, you may legally be able to participate in the process and get a healthy discount of the total price.
If you are in a remote area or planning an off-grid system, you may be able to do it all yourself, especially if you are in a state or locality that allows you, the homeowner to act as your own electrical contractor.
I know there are a lot of places out there where it is legal for you to do your own work and the (usually county or municipal) inspection officials will deal with you directly, and for those of you in these areas, it's mostly an issue of whether you have or can learn the requisite skills.
So What skills are required to install panels For regular PV panels, you need to handle a lot of rectangular panels about 36 inches wide, 60 inches long, up to 2 inches thick and weighing around 55 pounds each.
Bear in mind that you need to mount these at an average angle towards the sun for your location, so that means installing a rack first.
For many people, the only place with sufficient space that is clear for sunlight is on the roof, so that adds to the complexity and danger.
Once you have the individual panels in their racks, you can do the interconnections.
Bear in mind that any time there is light falling on the panel, it is producing some power, so these connections are essentially hot any time you can see well enough to make the connection.
Each panel will have to be connected to the charge controller though a series diode that keeps from discharging the batteries through the cells when they are at a lower voltage than the battery, unless the charge controller has one built in for each panel connection.
If your charge controller doesn't have individual connections for each panel, you will need the series protection diodes anyway.
Your charge controller will connect to your battery bank.
The wiring between the panels and charge controller should be large enough gauge to prevent excessive voltage drop, or you will be wasting some of your precious energy by heating up the wire instead of charging the battery bank.
The battery bank should be in a well ventilated room separate from your home, and have a direct vent to the outside.
It should be well insulated so the batteries are not exposed to excessive heat in the summer or freezing temperatures in the winter.
There should be sufficient space that you can work around the batteries safely, and remove and replace any single battery without crowding or bumping into the others.
You will need to store some maintenance equipment as well, and most people keep it in their battery room.
The distance from the panels to the battery room should be as short as reasonably possible, as the longer you have to run to get to your panels, the larger gauge the wire will need to be to prevent excessive voltage drop.
It really doesn't matter as much how far it is from your inverter to the home, as AC power loss isn't nearly as great as DC over longer wires.
Plan on having your inverter in the same place as your batteries so the connection to the batteries is very short.
You may be pulling some heavy current at times from the battery bank, and this connection is the most critical as relates to wire size.
The best layout I've seen is a small building with a battery room and and immediately adjacent room for the charge controller and inverter.
This way, the charge controller and inverter aren't exposed to the possibly corrosive gasses generated by the batteries during their charge/discharge cycle.
Connection to the home should be through an approved disconnect or transfer switch that feeds the main power panel.
At this point, I should bring up another possibility, that of having an "off grid" system connected to a house that is also on the grid.
In this sort of system, your solar system is not connected to the home at all during much of its life, but when you have enough power in the batteries and/or a nice day with plenty of sunshine, you can throw the transfer switch over to the solar system and run on it.
If you don't have enough power or capacity for a large current draw (perhaps you need to run the washing machine and your system or inverter isn't big enough for it) you can throw the transfer switch over to the main grid connection.
This is very similar to the way a standby generator is connected to a home that is on-grid in a location that experiences enough power outages to make it worthwhile for the additional cost of the generator and transfer switch.
Another quick note about generators.
If you are in a remote area and have an off-grid system, you'll probably want to have a generator available as well.
This can be used in either of two ways.
One is to use it only to charge the batteries when they are low, and another is to connect to the house in place of the solar system when you have higher needs or the solar system batteries are low.
The main difference is the size of the generator.
I know people that have a relatively small (1000 to 3000 watt) generator that they use only to charge the batteries when the panels are not producing enough or the batteries are low.
The use here is relatively low fuel consumption over a greater amount of time to keep the batteries topped off.
The other method, and I also know people that use this one, is to connect the generator to a transfer switch and take the entire home load on the generator.
This requires a larger, more fuel hungry generator, but can result in lower run times.
If you do go for a larger generator, consider a low-rpm diesel.
They tend to be better on fuel and because they run at lower rpm they last a lot longer.
The net running cost of either approach seems to be about the same, given similar energy demands as near as I can tell from the anecdotal evidence presented by the individuals that will talk about their systems.
Generally speaking if their system is doing what they want, you can't shut them up, and if it's not performing up to their expectations, you can't get a word out of them unless they're seeking advice.
Sounds like pretty normal human behavior to me.
As you can see, there's quite a lot that needs to be done to get an effective and economical solar electric system in place and working properly.
In many instances, this is within the capabilities of a careful and dedicated DIY-er.
If this fits your description, great, but be sure to get more detailed instructions and plans before you take on even the smallest of projects of this type, as you are dealing with potentially lethal voltages if something goes awry.
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