Since 1999 we've helped people across the world design complete solar panel systems for homes, off-grid or on-grid, tiny homes, science projects, schools, colleges, commercial installations and remote lighting to name a few. Check out our off-grid sizing and grid-tie sizing calculators to help you started and figure out how many panels you need.
Be sure to watch any one of our newest videos on solar panels, including our popular video on the difference between monocrystalline and polycrystalline below. To learn more we recommend also watching our educational videos in the Resources tab above. Be sure to scroll down to view our complete listing of what altE offers sortable by cost, watts, volts and cost per watt.
How Do Solar Panels Work?
Mono vs Polycrystalline Solar Panels
Shading and Solar Panel's Voltage and Current
Solar Power at Different Angles to the Sun
|Product Name ↓||Volts||Watts||$ / Watt||Price|
|altE 5 Watt 12 Volt Solar Panel||12 V||5 W||5.83||$29.15|
|altE Poly 10 Watt 12V Solar Panel||12 V||10 W||4.90||$49.00|
|altE Poly 100 Watt 12V Solar Panel||12 V||100 W||1.89||$189.00|
|altE Poly 100 Watt 24V Solar Panel||24 V||100 W||1.89||$189.00|
|altE Poly 120 Watt 12V Solar Panel||12 V||120 W||1.66||$199.00|
|altE Poly 140 Watt 12V Solar Panel||12 V||140 W||1.64||$230.00|
|altE Poly 200 Watt 24V Solar Panel||24 V||200 W||1.50||$299.00|
|altE Poly 200 Watt 24V Solar Panel - SCRATCHED||24 V||200 W||1.34||$269.00|
|altE Poly 30 Watt 12V Solar Panel||12 V||30 W||2.63||$79.00|
|altE Poly 50 Watt 12V Solar Panel||12 V||50 W||2.38||$119.00|
|altE Poly 60 Watt 12V Solar Panel||12 V||60 W||2.32||$139.00|
|altE Poly 80 Watt 12V Solar Panel||12 V||80 W||1.99||$159.00|
|Ameresco Solar 20J 20W 12V Solar Panel with J-Box||12 V||20 W||9.75||$195.00|
|Ameresco Solar 30J 30W 12V Solar Panel with J-Box||12 V||30 W||8.97||$269.00|
|Ameresco Solar 40J 40W 12V Solar Panel with J-Box||12 V||40 W||6.89||$275.74|
|Ameresco Solar 50J 50W 12V Solar Panel with J-Box||12 V||50 W||5.90||$295.00|
|Ameresco Solar 90J 90W 12V Solar Panel with J-Box||12 V||90 W||4.43||$399.00|
|Canadian Solar 255 Watt Smart Module with SolarEdge Optimizer||20 V||255 W||1.12||$285.00|
|Canadian Solar CS6P-250P 250 Watt Poly Solar Panel||20 V||250 W||0.84||$211.00|
|Canadian Solar CS6P-255P 255 Watt Poly Solar Panel, Black Frame||20 V||255 W||0.85||$217.77|
|Canadian Solar CS6X-305P 305 Watt Poly Solar Panel||24 V||305 W||0.89||$272.67|
|Canadian Solar CS6X-320P 320 Watt Poly Solar Panel||24 V||320 W||0.97||$310.00|
|Kyocera KD140GX-LFBS 140W 12V Solar Panel||12 V||140 W||1.97||$276.38|
|Kyocera KD140SX-UFBS 140W 12V Solar Panel with J-Box||12 V||140 W||2.14||$299.00|
|Kyocera KU265-6MCA 265W 20V Solar Panel||20 V||265 W||1.05||$279.00|
|Schuco 235 Watt Poly Solar Panel||20 V||235 W||0.75||$177.00|
|SolarWorld 260 Watt Solar Panel, Sunmodule SW260 Poly V4.0 Frame||20 V||260 W||0.94||$245.00|
|SolarWorld 270 Watt Solar Panel, Sunmodule 270W Black Mono V2.5 Frame||20 V||270 W||1.02||$275.00|
|SolarWorld 275 Watt Solar Panel, Protect Sunmodule 275W Mono BLACK, V4.0 Frame||20 V||275 W||1.31||$360.00|
|SolarWorld 275 Watt Solar Panel, Sunmodule 275W Black Mono V4.0 Frame||20 V||275 W||1.00||$265.00|
|SolarWorld 280 Watt Solar Panel, Sunmodule SW280 Mono V4.0 Frame||20 V||280 W||1.00||$280.00|
|SolarWorld 285 Watt Solar Panel, Sunmodule SW285 Mono V4.0 Frame||20 V||285 W||1.07||$305.00|
|SolarWorld 315 Watt Solar Panel, Sunmodule SW315 Mono 33MM||24 V||315 W||0.97||$305.00|
|SolarWorld 320 Watt Solar Panel, Sunmodule SW320 Mono V4.0 Frame||24 V||320 W||0.89||$286.00|
|Sonali Solar 10 Watt 12V Solar Panel||12 V||10 W||6.50||$65.00|
|Sonali Solar 20 Watt 12V Solar Panel||12 V||20 W||3.75||$75.00|
|Sunwize SW-S40P 40W 12V Solar Panel with J-Box||12 V||40 W||3.98||$159.00|
The term solar panels is often used for a few different types of products that produce energy by collecting sunlight. We most commonly use the phrase to refer to solar modules that convert sunlight directly into DC electricity (aka "photovoltaic solar modules"). Less frequently people will use the term in reference solar thermal collectors or solar air heaters, the first usually heats a liquid like water and the second heats air directly. Here at altE when we say 'solar panels' we mean the ones that produce electricity.
A fairly oversimplified way of saying how solar panels work is that rays of sunlight hit solar cells and push the electrons in the cell through the connected leads and wiring, creating electricity. This electricity is in one direction, so it is called DC for direct current, as opposed to AC (Alternating Current) where the electrons are going backwards and forwards repeatedly, 50-60 times per second for the common household. That why for most solar panel system installations you need to have an inverter to change the DC electricity to AC and make it useable with your home's appliances.
Said less simply, on one side of the solar cell there's an overabundance of electrons and on the other side there is a lack of electrons. Solar panel manufacturers create this static imbalance of positively and negatively charges on the cell by doping each side of the silicon solar cell with different chemicals (e.g. phosphorous on one side and boron on the other). Wires or soldered leads are effectively connected to each side of the cell. The positive and negatives wires go to what ever you want to charge or power. Connecting the leads in itself to an electrical load, while closing the current path, does not allow to the electrons to flow despite the positive and negative imbalance. It takes sunlight hitting the silicon in the solar panel's cells to loosen up electrons. And as soon as they a freed up they immediately start flowing through the wires to power your electrical loads. The more sunlight shines on the cells, the more electrons loosen up, the more electrical current flows and the more power the solar panel produces. Hot diggity.
We have created a handy, more in-depth overview of how solar panels work at our altE Solar Blog. It goes into some of the juicey details of not only how the photovoltaic effect works but also how solar cells work together to create different voltage solar panels, and what all the various ratings that go with solar module specification brochures mean.
We're guessing you wouldn't have come here if you didn't have a hunch they probably were. But just in case, let's quickly review when solar panels are practical for homes and when they're not. If you own your own home or cabin and you have (or a tiny home who can be parked such that... ) a roof that roughly points south with no shading by trees, hills, other homes from around 9AM to 3PM then you have some prime real estate for putting solar panels on.
The cost of solar panels has dropped significantly in the last several years, making it such that with tax incentives or rebates a grid-tie solar panel system will pay for itself in just a few years. Essentially for the price of a few years electricity you get 25 to 35 years of electricity. In fact, the solar panels themselves will probably keep on producing electricity at a lower rate for even decades after that.
Solar PV panels are not practical for locations that get lots of shade throughout the day. That said, with advent of micro inverters and grid-tie inverters that have DC optimizers that are connected to each individual solar panel, some locations with a little bit of shading can still make good sense.
We wrote an article in the altE solar blog that cover this topic. Basically, it depends on what is most important to you - brand, price, efficiency, where they are made, quality of the solar manufacturing process, etc. We highly recommend giving it a quick read.