Solar - DIY


Batteries - see the diagram in the middle of the page

Roof-top installation: - lots of information

STC / PTC rating:

Sizing: - Sizing Your Solar System - designing your system - done reading

Experienced installer will make sure all electrical connections are properly installed and insulated to minimize fire risk. Route cables properly. Appropriate sized electrical cables should be mounted in closed metal conduits. No loose cables should be present. Cables should be routed outside the building or enclosed in a fireproof duct.

Energy performance ratings for PV modules include the following:

  • Peak Watt — Measures the maximum power of a module under laboratory conditions of relatively high light level, favorable air mass, and low cell temperature. These conditions are not typical in the real world.
  • Normal operating cell temperature — Measures a module's nominal operating cell temperature after the module first equilibrates with a specified ambient temperature. It results in a lower Watt value than the peak-Watt rating, but it is probably more realistic.
  • AMPM Standard — Measures the performance of a solar module under more realistic operating conditions. It considers the whole day rather than "peak" sunshine hours, based on the description of a standard solar global-average day (or a practical global average) in terms of light levels, ambient temperature, and air mass.

Because the panels are fixed in place, their orientation to the sun is usually at an angle that is less than optimal. Therefore, less energy per unit area of array is collected compared with that from a tracking array. This drawback, however, must be balanced against the higher cost of the tracking system.

Note that there's no reason you have to put the system on the roof. If you're willing to give up some yard space, you can put the panels on poles on the ground. This is a good choice when the roof is shaded by trees and doesn't get enough sun. Putting the panels on the ground is also nice because then the panels can be easily arranged at the optimum angle to get the most sun, while on the roof you're limited by the ridgeline of the house.

For home energy, it's generally better to use the method above: Start with your monthly needs for electricity, then calculate how big a system you need. But if for whatever reason you want to know how much energy you can get from a solar panel, here's how to calculate it. First start with the number of hours of "peak sun" you get per day. That's easy: In our map above, it's 4 hours for green, 5 hours for yellow, and 6 hours for orange. Then multiply that by the peak output of your panel, then by the number of days per month. For example, for a panel rated at 150 watts in New York, we'd have:

4 hours peak sun x 150 watts panel x 30.5 days per month ÷ 1000 kWh/watt-hour = 18.3 kWh/mo.

Battery units require an array of additional hardware (batteries, battery enclosures, battery charge controllers, and separate sub panels for critical load circuits)

How can I figure out the size of the battery system that I will need?

Here's how you can find how large a system you need to generate as much energy as you use:

  1. Figure your daily usage. If you use 900 kWh/mo., that's 900 kWh / 30.4 days per month = 29.6 kWh/day.
  2. Figure how many kWh you need to generate each hour. From the map above you can see that if you live in a yellow area that you'll get 5 to 6 hours of peak sun per day on average. We'll call that 5 hours/day to be conservative. Since you need to generate 29.6 kwH/day, you need a 29.6 kWh / 5 hours = 5.92 kWp system.
  3. Add a safety margin. Multiply by 1.25 to account for shading, dust, and bad feng shui. So 5.92 kW x 1.25 = 7.4 kWp. We need a 7.4 kWp system.

Each 1 kWp of system takes about about 100 s.f. (10' x 10') of roof space.

What it comes to solar, do we have to do everything ourselves?

No. We can do everything ourselves from soldering cells to make panels and arrays if we want to, but we do not have to. We can buy professionally manufactured solar arrays and mounting kits, and wire them together if we know what we are doing. Solar arrays can produce electricity at a dangerous level, so make sure that we know what we are doing. If we are not sure, it is better to hire a professional installer.

What is power?

Power (with electricity) is voltage times current, or


If you plan to purchase a professionally manufactured solar panels, but plan to do the installation yourself, what should you be aware off?

  1. Check the DSIRE database for available incentives.
  2. Check with your local city government (building code) for applicable requirements, rules and process for getting a permit and inspection.
  3. Check with your local utility company for applicable rules and processes. Most utilities have an information package and a person who specializes in the utility requirements.
  4. Review how much electricity you use now. Solar panels are still expensive. See how you can make your home more energy efficient first without installing solar panels. You may want to install insulation, trade your old application for a more energy efficient application, etc. Do those things first if possible.
  5. Estimate your remaining energy consumption, and then determine how much of that you would like to replace with solar panel. Look up your state on DSIRE to learn about net metering rules where you live, including how much you can get paid for generating excess power.


How much can I save with DIY solar panels?

Solar panels and systems are no longer exotic specialty items. In fact, you’ll find them at major retailers about as cheap as they can be found. For the DIYer determined to shave up to $5,000 from the cost of solar installation, off-the-shelf panels and converters are available.

Here’s a partial rundown of who has them:

  • Best Buys
  • Costco
  • Home Depot
  • Lowes
  • Ikea
  • Walmart

What should I be aware of when consider buying solar panels from Costco, Lowes, Home Depot, etc?

  • Ease of installation, whether we need to drill holes in the roof
  • Warranty
  • Whether grant or subsidies from federal government, state government is available or eligible.
  • Energy Star, the federal program that promotes energy efficiency, doesn’t rate solar panels. Look for an installation company that offers a warranty on the system for at least 20 years. If feasible go with an installer that’s familiar with the permit process of your local zoning board. According to Hanis, getting a permit can be one of the most challenging aspects of a solar project.
  • Make your home efficient first. Take fundamental steps to improve your home’s energy efficiency before resorting to solar panels. Conduct your own energy audit, seal windows and doors, and replace old appliances. Simply adding insulation to an attic can lower heating and cooling bills by 10% to 50%. A tube of caulk and a few rolls of fiberglass insulation cost a whole lot less than solar panels.
  • Before you install solar panels, be sure your roof is in good shape. If it isn’t, you might need to shell out $5,000 or more on repairs to make your roof structurally sound. This expense doesn’t count toward the federal tax credit. You might also need to cut down trees that block direct sunlight. Energy Star, the federal program that promotes energy efficiency, doesn’t rate solar panels. Look for an installation company that offers a warranty on the system for at least 20 years. If feasible go with an installer that’s familiar with the permit process of your local zoning board. Getting a permit can be one of the most challenging aspects of a solar project.
  • It is not cost-effective. It takes a lot of time and hard work to soder them together, get them sealed, connected to battery bank, or get them certified and installed and inspected by the city and approved by the utility company.

What are the hidden dangers, costs (including maintenance costs), disadvantages, catches, or gotchas associated with DIY solar panels versus professional solar panels?

What are the best brands?

  • Others to be added to this list

Can home owners get rebate or grant to help pay for solar panels?

Not for DIY.

How reliable are solar panels? How long do they last? What should I be aware when buying solar panels? How long do the manufacturer warranty the solar panels?

The durability of DIY solar panel vary depends on the quality of the materials that you use, how well you solder, and seal the panels. Professionally manufactured panels are guaranteed to last about 25 years, but read the warranty.

Why do some people say that DIY solar panels are not recommended?

  • Professional solar installers go through a significant amount of training to be experts in their trade, with some even receiving advanced accreditations like a NABCEP Certification.
  • Leave it to the professionals. Most likely, you are not a professional electrician. Would you install your own central air conditioner or furnace, or rewire the electric in your house? Likely not, you’d leave it up to professionals to do it, which is exactly what you should do with installing solar panels. Although sunlight seem gentle, solar panels can be combined and arranged in such a way that can cause electrical fire if overloaded, especially if it is connected to the grid.
  • Because of the risk of creating electrical fire, your solar panels need to be certified. The process of getting your solar panels certified can be complicated if you are not familiar with it. If you hire a professional, make sure that the professional knows the process of getting your solar panels certified. Ask for referrals. Homemade solar panels do not have the proper certifications to qualify for the state and federal tax rebates. Without these certifications, you wouldn't be compliant with the building/electrical code or insurance companies. It would take thousands of dollars and several months to get your panels listed by a NRTL(Nationally Recognized Testing Laboratories).
  • You should never put high powered, homemade panels consisting of wood and/or plastic over your home or flammable material. You would want to mount them on bare ground, a concrete surface, etc.
  • The standard life span of solar panels professionally installed by a solar installer is 25 years; whereas, DIY solar panels are said to not last very long and the efficiency will decrease over a short period of time.
  • Maintenance will be much more demanding and with maintenance comes cost. This isn’t ideal because it could very well turn into a full-time job and you will most likely not get the type of investment you want.
  • Another initial investment you must make is getting your DIY solar panels certified. This process takes months and can cost you thousands of dollars.
  • You will have to ensure that the DIY solar panels are safe, getting them inspected by an electrical inspector, as well as complying with any regulations or standards your power company requires. Working with a consumer top-rated (and certified) solar installer will help make these processes run smoother.
  • A small misjudgment of the condition of your rooftop can essentially cost you thousands of dollars in repairs if not inspected properly. Knowing how and where to position your solar panels are incredibly important.
  • You also have to have the tools, workshop, talent, drive and budget to follow through to the bitter end on these projects. And honestly, you won't be displacing that much real electricity for your household, unless you have several free months or years to throw away.

What is a blemished solar panel?

An alternative for off grid or other solar projects is getting blemished solar panels. ( These type of panels have small blemishes that don't really affect the output of the panels. You can get these type of panels for $2.50/w up to $4/w including a 25 year warranty. These types of panels are not UL listed. The prices of commercial, UL listed solar panels are currently going for $4-5 per watt. See

With the electricity / energy captured by solar panels, can we use it to power machine or chemical reactions similar to photosynthesis that happens inside plants to remove CO2?

What are the tools that I will need if I want to do a DIY solar panel?

What materials do I need to do a DIY solar panel?

What are the components of a solar panel?

How much do you really save with DIY solar panel as compared to commercial professionally installed solar panel of equivalent output?

What is the URL for DIY solar forum?

What are some URLs on DIY solar?

Why do I need to vacuum seal DIY solar panels?

Lexan is a plastic. Plastic leaks air over time. See

What are the components of a photovoltaic (PV) system?

  • PV modules (groups of PV cells), which are commonly called PV panels
  • one or more batteries
  • a charge regulator or controller for a stand-alone system
  • an inverter for a utility-grid-connected system and when alternating current (ac) rather than direct current (dc) is required
  • wiring
  • mounting hardware or a framework

In an off-grid system, if my solar panels generate more power than I use and my battery can store, is there any risks or damages to my solar panels or components?

Is DIY solar panels a reality?

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