Solar panels are the key to harnessing energy from Sun and converting it to photovoltaic (PV) electrical power.
Solar panels are made of individual cells made from layers of semi-conductive material (usually silicon, boron and phosphorus). When light strikes the solar panel a photovoltaic effect takes place which generates electricity.
Did you know that an individual solar panel can be made up of 60, 72 or 90 cells?
Let’s explore a little more about solar panels and go into more detail.
- How do solar panels work?
- Types of solar panels
- Solar panels for home
- Solar panels for camping
- Solar panels for RV
- Best solar panels
How do solar panels work?
Solar panels convert light energy from the Sun into electrical energy.
This happens when light strikes the solar panel cells which are made of a “sandwich” of negative phosphorus and positive boron semiconductor material separated by a silicon layer. Electrons in the material are knocked loose and move between the plates to form an electrical current.
Each cell produces a small amount of power but when cells are combined in a solar panel, and when solar panels are combined in an array, a lot of electrical energy is produced.
Types of solar panels
There are different types of solar panels and each has specific advantages and pricing.
The type of solar panel you choose for your own solar installation depends on your budget and system requirements.
Let’s take a look at the different types.
Monocrystalline solar panels
Monocrystalline solar panels are made from a single silicon crystal which is carefully divided into wafers.
Monocrystalline panels have a uniform texture and can be easily identified thanks to their dark black color.
Features of monocrystalline solar panels:
- Long lasting
- Very space efficient
- More energy efficient
- More expensive to make
- Up to 50% of the silicon crystal is lost during production
Polycrystalline solar panels
Polycrystalline solar panels are produced from many different silicon crystals which are melted and molded.
The molding effect gives these types of panels a very geometric, square shape and since all the crystal fragments are used there is very little silicon wastage.
Features of polycrystalline solar panels:
- Less expensive to produce
- Less efficient in terms of space and energy conversion
- They are less tolerant to higher temperatures
Passivated Emitter and Rear Cell (PERC)
PERC solar panels are a recent innovation which makes traditional solar panels more efficient.
The PERC technology is the extra layer that is added to the back of the solar panel. This layer reflects light BACK into the panel so that the photovoltaic effect is enhanced.
PERC panels create more electricity from the same amount of sunlight compared to traditional panels.
Features of PERC panels:
- More solar radiation is absorbed by the panel
- Higher energy production
- Ideal for small spaces or limited roof surfaces
- Slightly more expensive than regular panels
- More efficient power producers
- Perform better in high heat environments
Since PERC panels use the same manufacturing process as traditional panels, it makes complete sense to produce PERC panels in the same factories. As a result they are only slightly more expensive to produce than non-PERC panels due to the extra layer of material.
Overall, PERC panels have a lower cost per Watt than traditional panels.
Flexible thin-film solar panels
You might see flexible thin-film solar panels on RVs or solar backpacks. These panels can bend and are therefore useful for a number of purposes, but far less efficient.
Thin-film panels are usually made from one of the following.
Cadmium telluride (CdTe): has a lower carbon footprint and low cost but cadmium is toxic and difficult to recycle.
Copper indium gallium selenide (CIGS): the most efficient combination of elements for flexible solar panels (although not as efficient as regular solar panels).
Flexible solar panels are great for caravans, RVs, camping and a whole bunch more. They are portable panels and some can even be folded.
Modern flexi-panels are tough, adaptable and can do a great job for powering small appliances, batteries and devices.
Solar panels for home
Your home has very specific energy requirements and the panels you get are dependent on your budget, your roof, the weather and sunlight in your area and your overall power system.
Check out a real-world example of what solar costs for a 3 bedroom home.
You can install solar panels on your roof, carport or even an open piece of land next to your house.
Solar panel systems for the home can be:
- Off-grid: you are completely independent from the main electrical grid system in your area
- Grid-tied: your solar system is linked to the grid so you are able to feed electricity into the grid from your solar panels (and get back energy credits from the government)
You can also choose to go 100% off-grid and get all your energy from solar, or you can have a hybrid system where you get most of your energy from solar and then the grid tops up the rest.
Remember that solar panels need to be cleaned and looked after.
Solar panels for camping
Camping is a remote activity and you are far away from any reliable energy source. Why not take an energy supply with you?
Solar panels are great for campsites and can be set up to power small appliances and devices while you relax in nature.
You can set up rigid panels (which are more efficient) or take along smaller, portable and flexible panels.
Hook them up to a battery and let the sun charge your battery. You can then power your campsite with energy from the sun, even at night.
What size solar panel do you actually need for camping?
The biggest strain on your energy requirements at a campsite is usually your camping fridge. If you’re looking at using a 12 V camping fridge with 2.5 Amps of average power consumption you will need a fairly good panel (or sets of solar panels). Aim for 150W to 250W and you should have enough power to also power some other campsite essentials such as cellphone chargers and LED lighting.
You can get some pretty decent solar panel kits for camping that fold up and produce the power you need.
Go for the following solar camp kit features:
- High performance panels (e.g. PERC Poly)
- Adjustable support so you can expose the panels to direct sunlight at any angle
- Charge controller to regulate and manage the power from the panels
- Sturdy frame and carry handles
- Carry bag for easy set up
- At least 5 meters of cable with a plug point
Your solar kit will charge your 12 V batteries which will power the campsite even when it’s dark or if there’s bad weather.
Solar panels for RV
Your RV has a number of energy requirements (lights, fridge and other appliances, device charging) and how much power you need depends on a number of factors. People charge up at campsites and other places with access to grid power, but more and more RV enthusiasts are looking at solar power as an alternative.
How many solar panels does your RV need? This depends on how many appliances you have, what your energy usage patterns are and how much sunlight you have available to you.
You should calculate your daily energy requirements and use that to calculate the daily watt-hours of electricity you need per day. Like a regular home solar system, you can use similar calculations to determine how much power you need to generate from solar.
You will need solar panels (polycrystalline, monocrystalline or the flexible, amorphous type), a charge controller and a battery pack to hold the charge for when you need it.
You can get all of this when you buy a good RV solar power kit with all the essential components bundled. Some kits even offer flexible solar panels for your RV.
Let’s look at some of the basics of RV solar you should be aware of:
- Understand the basic electrical needs of your specific RV
- You will need sunlight, solar panels, a charge controller, cabling, connectors and batteries to store the energy from the sun
- Solar electrical energy can only get you so far and should be avoided for heating e.g. stove tops
- Most RVs have very small battery storage capacity and adding more solar panels won’t increase your energy capacity unless your battery storage capacity also increases
- You’ll need fuses and breakers between the panels and the charge controller, and your charge controller and the battery pack, to protect your system
- Start small and scale up over time as your budget allows
- You’ll need mounting brackets to install the solar panels to your RV roof as well as sealant to stop any leaks from drill holes
- Panels can be wired in series or in parallel, with different effects and benefits
- First connect your charge controller to your batteries and then you connect your solar panels to your charge controller
- Get AGM or lithium ion batteries – they are more expensive but more effective and last longer than lead acid batteries
- Get a charge controller that is appropriate for your battery chemistry type (AGM vs lithium ion vs lead acid etc)
The inverter’s job is to convert DC power (Direct Current) from the solar panels to AC power (Alternating Current) that your appliances can use. Your general home appliances cannot be run on DC power only – you need the inverter to make the DC power usable.
How do you know which solar inverter is best for you?
Did you know that it is more important to have a premium inverter than premium panels? You can get away with cheaper solar panels but you shouldn’t skimp when it comes to your inverter.
Types of inverters:
- Central (or string) inverters: these inverters are installed inside your home or garage close to your meter and are about the size of a small suitcase
- Microinverters: these are installed underneath each solar panel individually and are about the size of a tablet or book
- Optimizer-based: this type of system has a central inverter but also individual power optimizers for each solar panel (to account for shade, cloud or weather)
The microinverter and optimizer-based systems allow for each panel to be independent and have the required Rapid Shutdown safety system. These systems are usually more expensive than the Central inverter system and are really only necessary for homes where there is shade or a roof shape that doesn’t allow for constant sunlight.
Features you should look for in an inverter:
- European-made products are higher quality but more expensive
- Provides monitoring data with all the key data you need
- Made by an experienced and established company
- Great customer service
- Warranty of at least 20 years
- Intelligent MPP tracking for shade adjustments (only required for shady conditions)
- Choose a power optimizer that can be used with any inverter for greater flexibility
Your battery backup system holds the power you need when there is no other source of energy. This happens when the grid is offline or when it is night time and your solar panels are not producing power. You can also use battery power instead of grid power if your area has peak time tariffs or special charges at specific times. This will help you save money by using battery power instead of grid power.
The size of your battery system should match your daily energy needs – as we saw above with the solar RV systems, you can’t keep adding more and more solar panels if your battery system doesn’t also grow.
For example, a single Tesla Powerwall (which has a built in inverter) currently provides 13.5 kWh of electricity per day but your daily energy needs might be a lot higher. Our 3 bedroom house uses 40kWh per day.
Batteries come in various types but the important differences are as a result of the battery chemistry:
- Lead acid batteries: cheaper but don’t last as long
- Lithium ion batteries: more expensive but last longer and more effective which include NMC (Nickel, Manganese, Cobalt) and LFP (Lithium Iron Phosphate) batteries
Your battery system should be set up in a room in your house or garage with good ventilation and protected from extreme temperatures and weather.
Features and factors you should look for when buying a battery system:
- Power output
- Warranty (must be more than 10 years at least)
- Reliable company with a solid history
Make sure your solar installer does a thorough analysis of your energy needs before recommending a battery system.
Best solar panels
How do you know which solar panels you need and which are the best for your energy requirements?
There are so many solar panel manufacturers out there that is can be very confusing. Your solar installer will know what you need and make a great recommendation in their quote, but it helps you do some of your own research for your peace of mind.
You need to consider the company manufacturing the solar panels. Are they trusted? Have they been in business for a while? What is their reputation?
Power output, efficiency, power density and temperature coefficient are also important factors to compare.
Price is a factor too but remember you don’t need to get the most expensive panels for peace of mind.
Some panels include a reflective layer at the back of the panel (PERC) which increase the efficiency of the panel at a negligible additional manufacturing cost.
If you have plenty of roof space you don’t need to fork out for higher power density panels – the lower density panels will work just fine since you have the space to install more.