1. Basic understanding of how solar power can work in your home
2. Introduction to Photovoltaic panels.
3. How photovoltaic panels (PV) work.

Solar power is getting a lot of attention these days because of skyrocketing oil prices. What makes solar power unique is its ability to make energy from something so abundant which is the sun. But how does this work?

Solar power is possible thanks to something called photovoltaic panels. Photovoltaic panels or PV panels are also known as solar cells.

Photovoltaic panels are devices that converts energy from sunlight directly into electricity. This results in a voltage buildup across two electrodes as electrons are moved from one place to another. Photovoltaic panels or solar cells are used to power electric devices or even charge batteries.

The first practical application was to power orbiting satellites or spacecraft in space where the use of fossil fuels was impractical. Nowadays, because of the advancements in technology and the slowly decreasing price tags of photovoltaic panels, solar power is connected to the power grid to provide additional electricity.

Another common use of PVs are in off-grid systems where solar power is used to power structures that are in remote locations. Other applications are in powering boats, electric cars, public street lights and so on.

While there are tons of research on advancing photovoltaic panels, the most common material used as of today is silicon. The current average efficiency of converting sunlight into electricity using today’s PVs is around 12-18% and the cost of generating a watt or electricity is around USD4-8. This is inclusive of all components and installation from inverters to panels to mounts.

Looking toward the foreseeable future, we can expect photovoltaic panels to cost less and produce electricity more efficiently. Around the 40-50% range.

One thing we can all be sure of is the sun isn’t going away soon, so the more we rely on solar power and photovoltaic panels and the less we rely on fossil fuels and non-renewable energy, the better.

I get a lot of questions from people starting out with solar power on how to get the Amp Hour rating for the solar batteries they will be using. Here is a step by step on that…

• Determine which appliance or electric device will you power with your solar batteries via your solar power system and get their corresponding wattage input. For example:

light bulb (20watts).

• Calculate how many hours in a day will you run the above. For example:

light bulb (5hrs/day)

• Get the watt-hrs/day of each. For example:

light bulb (20watts x 5hrs/day = 100watt-hrs/day)

• Get the amp-hours per day by dividing the watt-hrs/day value by the voltage of the battery you will use, say 6V or 12V. For example:

100 watt-hrs/day divided by 12V = 8.33 amp-hrs/day

• Take into consideration the discharge level, usually 50%. For example:

8.33 amp-hrs/day divided by 50% = 16.66 amp-hrs/day or Ah

In conclusion, you will need at the least a 16.66 Ah rating battery to run a 20watt light bulb for 5 hours each day.

Here are some basic tips on how to extend the life of your batteries.

• Install batteries in sets. Do not replace one or two batteries only. The best practice is to install them all at the same time and replace them all at the same time too.
• Keep batteries in the correct temperatures as specified by the manufacturer.
• Avoid moving the batteries once installed.
• Make sure the battery connections are properly connected and there is not post corrosion.
• Do a regular yearly check up on your batteries. Test the electrolyte the voltage and charge of all batteries to see how good it is holding up and if they need to be replaced.

Deep cycle batteries are the exact opposite of your car batteries. While a car battery is designed to expend a high voltage for a short amount of time via the start engine phase, a deep cycle battery is designed to give out a constant voltage throughout a long time. Golf carts and boats both use deep cycle batteries.

Solar batteries that go on deep cycle batteries should never be allowed to discharge below 50%. Anything below 70% and your batteries will permanently lose capacity as sulphation starts to set in.

Here are some things to consider when it comes to solar batteries…

Temperature

One of the biggest factors affecting any kind of battery is temperature. There are batteries designed specifically for the area you want to install your solar power system. A cold climate would need a different designed battery from one that is made for hot and humid environments. Check your solar battery manual on the best way to keep them.

Mixing and matching

While it’s common to use different batteries in your remote control or any other electronic device, it isn’t recommended for your residential solar power system. It is important to purchase and install the same type of batteries all at once. Mixing different types, sizes, age of batteries is a definite no-no as the whole battery bank will take the state of the weakest battery.

Amp-hours

All batteries come with an Ah or Amp-Hr rating. A battery that has a 200 Ah (20hr reference) rating would give out 10amps for 20hrs before being discharged. The higher the Ah rating, the more expensive, heavier and longer will the battery hold a charge.

Battery Voltage

Most batteries come in 6V or 12V. To get higher voltage you simply wire these batteries in series and to get higher amp output, you wire them in parallel.

While the technology behind solar cells continue to advance every day, most solar cells are made up of mono crystalline silicone wafers with some trace elements used as coating. It produces solar electricity by making use of the photons that come from sunlight, have these photons hit and excite the electrons in the solar cells and thus produces electricity.

Each brand or manufactured solar cell wafer may have different wattage output, and to reach a higher wattage than what one solar cell wafer can produce, you simply combine more wafers into an array.

The main benefits of using solar panels is that it is very low maintenance and it basically produces electricity for free for the remainder of its life.

The only downside of solar panels is the cost of one of these, as with any new technology, the manufacturing cost have yet to scale to a sizeable amount before the cost of production can significantly lessen.

Here is an interesting video for you to get started on solar panels…

There are more types of solar inverters, but this is the essentials of what you need to know. I will go into more detail on future posts.

Another essential part of your residential solar power system is the charge controller.

The main purpose of the charge controller is to prevent the destruction of your batteries because of over-charging or even under-discharging. Charge controllers are regulators that go between solar panels and your batteries. It acts to keep your batteries charged at peak without overcharging.

For some, this isn’t an essential part of their solar power circuit, but if you’re using a small battery bank and you can afford to spend a little bit more for a charge controller, this is definitely worth it.

It’s like buying a car with safety airbags. You probably don’t think it’s worth much, but it counts when you need it. And besides, dead batteries due to over or undercharging and need to be replaced is always more of expensive in the long run.

So buy some peace of mind and get a charge controller fast!

Another common question I often get when it comes to solar electricity and residential solar power is whether you really need a battery bank and a charge controller. Isn’t connecting the inverter or any appliance directly on to the solar panel simpler?

The answer is yes, of course you could. But all you would be doing is risk breaking your inverter or appliance. With solar panels, the voltage it produces varies widely. On extremely sunny days it could produce a lot of voltage while on cloudy days it could produce very little.

This inconsistency is one of the major disadvantages of using solar power and why it isn’t anywhere near close to replacing traditional forms of energy yet.

Going back, with a battery bank, the load smooths out the voltage and basically insulates the inverter from any damage. Another benefit of a battery bank is that during cloudy or rainy days, when there isn’t enough sunshine to make significant power, the battery bank serves as a back up source of power.