Home Solar Power 101

Here’s What You Need to Know About Home Solar Power and How to Get Started

How many of us think solar power is a good idea but just never seem to get around to it?  Well maybe it’s time to take the first step towards solar.  It doesn’t have to be expensive and you can install it yourself.  As you become familiar with solar power on a small scale it’ll be easier to slowly scale it up to as much as a whole-house solar setup that can give you electric power when you lose power and could even allow you to live comfortably off-the-grid.

If you’re considering a whole-house solar setup you might also want to consider a contractor who specializes in solar installations.  There are some complex wiring considerations to either take your house off-the-grid to 100% solar, or to do a dual power setup using both the grid and your solar generated power.

The First Steps to a Solar Power Plan

It’s probably worth the time to do a quick review of how a solar power system works and the 4 key components that turn sunlight into electricity.

  1. Solar Panels
  2. Charge Controller
  3. Batteries
  4. DC to AC Inverters

1. The Solar Panels

Solar panels are measured and identified by their wattage output.  Most panels are 2-feet wide and 4-feet long and have an average wattage output of 100 watts.  Total wattage for some panels is higher, and some lower. 

A thing to keep in mind when totaling wattage delivered from a panel is that the wattage rating assumes the panel is perfectly aligned to bright sun at a 90-degree angle.  That happens briefly during the course of any day.  The sun moves across the sky in a southerly direction and as it travels from East to West the angle of the sunlight and its alignment with any solar panel will vary.  There are also clouds to consider which diminish the power of the sunlight.

The number of panels used depends on the end-use of the electricity generated.  If you’re simply powering a light in the chicken-coop or charging one wet-cell battery, one panel could suffice.  Most setups have multiple panels to charge batteries quickly or to manage larger power draws.

There are adjustable solar panel supports that attach to a roof that allow you to change the angle depending on the time of year.  During the summer the sun is higher in the sky.  In winter it’s lower.  This means getting up on the roof twice a year to adjust the angle but it’s worth it if you want maximum solar power output.

The roof is the location of choice for solar panels.  The ideal location is in a southerly direction.  A rooftop with a western or eastern exposure can also work but to a lesser degree.  If the only exposure is to the North another location for the solar panels should be improvised.

installing solar panels
installing solar panels

If you have any plans to have your house reroofed in the next year or two you should do that first before installing a large array of solar panels.  One panel is easy to remove temporarily, but a series of panels are usually connected to both support frames and wired together making removal and reinstallation complicated.

One of the factors that can limit solar panel exposure to the sun are obstructions.  Trees, neighboring buildings, hills and mountains can all block out sunlight.  Trees can be cut down if necessary, but buildings are permanent, hills can’t be relocated and who wants to move mountains.  If you’re in that kind of situation you may have to take a pass on solar power.  Or move.

2. Solar Power Charge Controller

solar charge controller
solar charge controller

The Charge Controller connects all of the cables from the solar panels to a bank of batteries and possibly to your home’s electric meter.  The reason you would tie-in to the grid through your electric meter is to gain energy credits from your local utility.  This varies from utility to utility, but some parts of the country actually have laws on the books mandating that a utility allow someone with solar panels to connect to the grid and receive a credit for any excess electricity they generate.

Advanced Charge Controllers have gauges measuring real-time solar panel output in watts or kilowatts (kWh).  They can also tell you what the current charge is in your batteries in addition to the current efficiency of your panels buy percentage. 

A critical function of a Charge Controller is to switch off the power generated by the panels when the batteries are fully charged.  As the batteries drain the Charge Controller will redirect power to further charge the battery bank. 

This function can also redirect power to your electric meter if you’re hooked up to the grid.  It will give you the option to only switch to the grid when the batteries are charged or bypass the batteries and direct power only to your electric meter.  The reason you would do this are those occasions when you’re away on vacation or simply not using electricity. 

3. Batteries

The traditional standard for storing electricity from solar panels are wet-cell batteries.  If you think of your car battery you’re thinking of a wet-cell battery.  They consist of a plastic case with two terminals on the top or top side and are filled with a combination of water and sulfuric acid.  This combination allows metal plates in the battery to hold a charge.

Wet-cell batteries come in a range of voltages including 6-volt, 12-volt, 24-volt and 48-volt.  The voltage you require is up to you.  Any of the lower volt batteries can be wired together to scale up the voltage.  Typically, the higher your power demands, the higher the voltage you’ll need.

Wet-cell batteries require periodic maintenance.  This usually involves adding distilled water to make sure the water levels in the batteries are consistent over time.  It’s also possible that additional sulfuric acid will need to be added to the batteries.  There is a gauge that looks like a turkey baster and draws the battery fluid into a reservoir where the acid percentage is measured. 

If you ever need to add acid to a battery always remember that it’s okay to add acid to a larger proportion of water, but never add water to a larger proportion of acid.  The water will vaporize in a cloud of acidic steam and cause serious injury.  Wear face protection and proper clothing whenever you add anything to a battery and always measure the acidity of the fluid in the battery before doing any maintenance.

It’s also important to store wet-cell batteries in a dedicated storage place that is vented to the outside of the home, and also provides heat to the batteries during winter. 

When batteries recharge, they give off small amounts of sulfur dioxide gas.  You don’t want this in the house.  Vents and even a small, solar powered fan to the vents are a good idea.

a solar battery bank
a solar battery bank

The reason you want to manage the temperatures surrounding your battery bank is that wet-cells don’t deliver as much of a charge when the weather is cold or freezing.  If you’ve ever started a car parked outside on a very cold winter morning you may have experienced the slow cranking of a battery that is less than 100% efficient.

A new alternative to wet-cells is the dry-cell, Lithium battery.  They require no maintenance and store the energy in the same way as a wet-cell.  Better yet, they can be easily and safely located in the house. 

The Tesla corporation has developed a dry-cell battery that is ideal for home solar power storage and they even have a product called the “Tesla Power Wall” which contains the batteries in or on a wall with appropriate gauges to manage input and output and display the current charge in the battery.

4. DC to AC Inverter

a solar inverter
a solar inverter

Electricity is delivered as a current of power.  It is delivered in one of two ways.  Direct Current (DC), and Alternating Current (AC).  The electric power that is generated by solar panels and stored in batteries is Direct Current.  Unfortunately, we live in an Alternating Current world.

A DC to AC Inverter converts Direct Current to Alternating Current to power most everything that runs on electricity in our homes.

The reason Alternating Current is so prevalent is because it’s easier and cheaper to transmit over long distances.  Direct Current is weaker and requires amplifiers to be placed frequently along any lengthy powerline to boost the current. 

But Alternating Current has one downside that could have outweighed its benefits in the early days of the electric age.  It’s extremely dangerous.  In fact, Thomas Edison who was a proponent of Direct Current once electrocuted an elephant to demonstrate the dangers of Alternating Current.  It was a cruel if not bizarre way to make his point, but the efforts of two men named Westinghouse and Tesla advanced the cause of Alternating Current and we live with it to this day.

However, there are some Direct Current options.  There are lighting solutions and even some appliances that run on Direct Current.  Because the Solar Power source of the Direct Current is relatively close to a home it doesn’t need the boost from transformers or amplifiers to travel long distances.  As a result, it’s possible to feed some DC to certain fixtures and appliances while using the inverter to power other fixtures and appliances that still require AC.

This is one of the things you need to sort out as you plan in the short-term and long-term with solar power. 

Estimating Your Home Energy Needs

If you are considering a whole-house or significant Solar Power installation, you need to audit your current energy usage and anticipate how that usage may be reduced by taking certain steps to live more energy efficiently.  Here’s how to approach this evaluation:

  • On every electric bill you receive you will find the amount of kWh or kilowatt hours you’ve used on a monthly basis.  This basis will vary by time of year, but you should have an idea of what your maximum and minimum usage is across the year.
  • Take stock of your current energy usage and see where you can reduce usage whether by buying more energy efficient lights and appliances, or simply switching to an alternative solution.  Quick energy saving efforts include:
  • Replacing incandescent lightbulbs with energy efficient bulbs or LED’s which can be powered with Direct Current.
    • Buying energy efficient appliances when it’s time to replace an old or broken refrigerator or water heater.
    • Insulating a home as efficiently as possible to keep it cool in summer and warm in winter and avoiding any costs or electricity to keep it that way.
    • Installing passive solar solutions like solar floor tiles in a room with direct exposure to sunlight.  They absorb heat during the day and give off heat at night.
    • Installing a passive solar water heater.  This is located on the roof to provide water pressure to the rooms below and to give the solar water heater the best exposure to the sun.  Water is pumped up to a reservoir where it’s heated across a series of pipes painted black to allow the sun to heat the water.
  • Practice energy efficient behaviors. This will become easier as you depend more and more on solar power because you will see the immediate effects of wasted energy.  There are various ways to do this:
  • Shut off the lights when you leave a room.  Make sure everyone else in the family understands this simple concept. This includes the TV.
    • Switch out to different solutions.  Use fans instead of air-conditioning to keep cool.  Install a wood-burning or pellet stove to relieve the energy burden of a furnace especially if it’s electric powered rather than natural gas.
    • Install timers on energy vampires like video games, modems, and other electronics that sap power 24-hours a day even when not being used.  They may not use that much power on their own, but when you multiply the number of electronic devices that are “always on” the energy usage adds up.
    • Close the doors!  Don’t leave the fridge door open for 5 minutes while you make a sandwich or leave the front or back door open when it’s very hot or cold while you unload the groceries.  Make sure others understand this as well.
    • Appoint a “Bed-Check Charlie.”  The last person to sleep should make sure everything’s off that doesn’t need to be on while everyone’s asleep.
  • Recalculate your energy needs after considering any changes you’ve made to determine your revised kWh needs on a monthly basis.  But make sure you add in one more thing….

The “Power-Draw” Factor

There are hidden energy spikes that we don’t always appreciate.  These spikes are the power-draws that certain electric motors require at start-up.  You’ll typically see these “spiking power-draws” on motors used in sump pumps, well pumps, refrigerators, furnace fans, and anything else that has a large electric motor to perform a function. 

These motors can draw as much as 1,000 watts at start up before going down to as low as 50 watts to maintain running speed. You need to build in a buffer for your total, monthly kWh for these motors.  It would be nice to replace them but some things like well pumps, sumps pumps and other appliances are difficult to switch out to alternatives.

Start Simple or Go All-In?

If you want to start simple, try to isolate an electric power need.  Power for lights in a barn, shed or detached garage could be a good place to start.  Lights and a small amount of heat in a chicken coop or pig sty is another option.  You could also setup a small-scale solar recharge station for electronic devices.  What you’re trying to do is find a way to get some experience with solar generated electricity without too much risk to necessary infrastructure. 

Once you’re found success with your modest solar setup you can think about scaling-up to a portion of your home.  Power for lighting only is a good place to start before you start thinking about powering the furnace, well pump and other appliances that have a high power draw and can run at significant wattages like clothes dryers and air-conditioners.

Solar power has significant advantages for outdoor lighting anywhere around your home or homestead especially for remote areas.  Those are other places to consider as your solar solutions grow.

Another solar solution to consider is a solar powered water heater or ways to either generate or capture heat from the sun to heat your house.  You may not be able to heat the whole house, but you can support your heating system with solar floor tiles or if you live at a very cold latitude, black shingles on your roof to absorb heat.

If and when you feel it’s time to make the big jump and go all-in on solar, it’s a real good idea to at least consult with a solar contractor.  By then you will be experienced enough with the concept and workings of solar power to hold your own in a conversation and especially in a negotiation for installation.  You’ll also have a very accurate grasp of your real power needs and you’ll  be aware of some of the realities that affect solar power generation.

Solar Power Realities

Your Location

This isn’t about living in the mountains or a deep valley where the sun rarely shines.  Various parts of the world get varying degrees of sunlight on an average basis.  In the U.S. most of the southwestern states receive the most sunshine on a daily and annual basis and are ideal locations for solar power.

Parts of the Midwest, especially in the Ohio Valley, and the Pacific Northwest get the least sunshine daily and annually.  You can still try a solar installation but it’s another good reason to start small and get some experience.  If your small-scale experiments disappoint, a large installation may do the same.

Local Weather

Even the sunshine state (Florida) gets a significant amount of rainfall and rain means heavy cloud cover.  Regardless of where you live, try to get an estimate of how many overcast days you have versus sunny days.  Solar power still works on an overcast day, but the amount of energy generated is reduced.  Seattle is another example of a location with significant cloud cover on a consistent basis that reduces the effectiveness of solar generated power.

Local Laws, Ordinances and Legislation

  • Take the time to understand any rules, regulations, ordinances, laws and legislation that affects solar power in your area.  Some could be to your benefit like tax credits for solar power expenses both federal and state.  There also grants for solar that you should consider. Some municipalities also offer tax breaks on local taxes for solar power installations.
  • The current federal solar energy credit is 30% of the cost of the system through 2019.  The federal tax credit decreases to 26% in 2020, then to 22% in 2021, and expires December 31, 2021.  There are even some states like Arizona that offer tax incentives for installing wood-burning heating solutions.  Most states and municipalities have websites where you can find more information about energy solutions, grants and tax credits.   
  • There are also some areas that restrict solar panel installations in close proximity to an airport.  The panels are highly reflective, and a large array could temporarily blind a pilot.  If you’re working with a solar contractor, they should know if these kinds of ordinances apply in your area.
  • Much like any other home improvements, many counties and municipalities require a permit and inspection for significant projects.  Once again, check with their websites to understand what is required for major projects.
  • If you live in an area with a Homeowners Association, check with them with regards to any policies or regulations affecting solar installations. 

So What’s it Gonna Cost?

The cost for materials and installation of a whole-house solar powered system will be proportionally less for new construction than it would be for a retrofit to an existing structure.  Like everything in life, prices may vary but a lot depends on the size of the property, the power needs and any offset as a result of grants or tax credits.

For smaller installations it’s a bit easier to identify costs, at least in a range.

  • An average 2 foot by 4-foot solar panel generating 100 watts will cost between $100 to $200.
  • Solar Charge Controllers range from $20 to $60 for small-scale solar power applications.
  • Wet-cell batteries cost as much as a car battery from $50 to $100 each.
  • Dry-Cell Lithium batteries range from $100 to $200 each.
  • DC to AC Power inverters range from $20 for a 100-watt inverter to $60 for a 600-watt inverter.  Larger inverters can put out significantly more wattage but for small-scale applications used for lighting only, 600 watts can handle most needs. That averages about 10¢ to 20¢ a watt with the average price decreasing as the wattage increases.  Here again, prices may vary.
  • There are also miscellaneous materials needed for a small-scale installation including wires and cables that will cost between $10 to $20 depending on their length. 
  • You might want to add in a book or two about solar installations in general and figure anywhere from $10 to $20.

Harvesting the Sun

There’s a great satisfaction once you have a solar power system installed.  For one, the electricity is free.  Sure, there was an upfront cost to get started, but once in place your solar power system will not only start to pay for itself, but if you’re hooked into the grid it will make you money. Solar power is another very smart step towards self-reliance and now may be the time to stop thinking about it and take that first step towards solar.

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