How much power you can get out of a given panel? We think lots of people think you can get what the manufacture rates the power at but unfortunately your highly unlikely to ever get that amount of power from the panel.
We found that in the process of selling solar panels. We regularly get asked why “my new 100 Watt panel is producing 70 Watts, is something wrong?” The short answer is NO, but let’s look at why this happens across the solar industry.
Standard Testing Conditions (STC)
A solar panel is first tested right in the factory. As the panel comes off the production line, a worker (or robot) places the panel on a “flash table” and hooks up the positive and negative leads to a measuring device. The panel is then “flashed” with fake sunlight. The connected electronics record a number of performance values including the panel’s voltage (volts), current (amps) and power (watts).
These testing conditions are called “Standard Test Conditions” or STC.
The electric output performance of crystalline silicon and thin film PV modules are generally measured under standard test conditions (STC), ensuring a relatively independent comparison and output evaluation of different solar PV modules.
1.Temperature of the cell – 25°C(77F). The temperature of the solar cell itself, not the temperature of the surrounding.
The important factor here is that the hotter it gets, the less efficient the solar panel becomes.
Solar Irradiance – 1000 Watts per square meter. This number refers to the amount of light energy falling on a given area at a given time.
1000 watts/meter^2, this is some pretty intense sunshine. This is done on a horizontal panel with the “sun” directly overhead for optimal angle of interaction.
Mass of the air – 1.5. This number is somewhat misleading as it refers to the amount of light that has to pass through Earth’s atmosphere before it can hit Earth’s surface, and has to do mostly with the angle of the sun relative to a reference point on the earth. This number is minimized when the sun is directly above as the light has to travel a minimum distance straight down, and increases as the sun goes farther from the reference point and has to go at an angle to hit the same spot.”
This condition approximately represents solar noon near the spring and autumn equinoxes in the continental United States with surface of the cell aimed directly at the sun. However, these conditions are rarely encountered in the real-world.
The manufacturer uses STC testing to sort panels by power and ensure that similar panels are sold and used together.
“STC stands for “Standard Test Conditions” and are the industry standard for the conditions under which a solar panel are tested. By using a fixed set of conditions, all solar panels can be more accurately compared and rated against each other.
Relationship of efficiencies
So now we build these factors into a relationship of efficiencies. The sunny summer months are great because the sun is close to directly overhead, like in the lab. However, the increase in heat reduces panel efficiency. In the winter months the panels are cold, so more efficient, but the sun is lower on the horizon so it fights through more atmosphere to get to our panel. On top of this, most panels do not point directly at the sun except for a fraction of the day, reducing efficiency again. This compounds with voltage drop, the lost power as electricity moves through wires.
Essentially there is almost always something(s) that prohibits solar production at lab settings, a factor that pulls down the panel from its rated wattage.
What does this mean in the REAL WORLD for you?
The solar panels won’t perform the way they do in lab-controlled STC in the real world.
It means we can expect to see between 67% to 75% of a panel’s rating when used. So if a 30 watt panel is in sunshine, you should expect 20-24 watts. This is the most you’ll see most of the time, less as the above factors add up to reduce power production. Even less as clouds and shadows block your panel. Less as dirt builds up on your panel. Each connection usually has a minuscule loss as well. All these individual nuances build into a visibly significant lower number than expected.
We are trying to adjust expectations through education. Some solar companies are even putting both rated watts and “true” watts on their panels to help solve this confusion. It’s like when auto companies started giving urban vs highway miles per gallon because no one was observing the potential efficiencies while commuting to work in stop and go traffic.
The “Bright” side: The opposite is true too. A solar panel placed at high altitude, in the cold, with the sun at mid-summer angles, while directly pointed at the sun, can produce above the rated watts for a panel! The other 99% of the time, however, you should expect less.
If any question or advice, Please contact us or call us in the following information from Mondays to Fridays.
Any wholesale request just call us or email us, thanks.
www.lensunsolar.com Tel: UK +44 2032875806 US +1 (323) 2845027 China: +86 15759769602 Whatsapp/Wechat: +86 15759769602 Skype: lensunsolar Email: firstname.lastname@example.org, email@example.com
Thanks for Gijs’s shared why he choose solar power and how it installed the solar panel on his tenttrailer Combi Camp. The following is his experience.
I started thinking about a good solution to be able to camp “self-sufficient” two years ago. I had several reasons for doing this:
1.Prices for electricity on campsites are very high in my opinion and this is a waste of money for a tap, a light and charging a telephone and / or tablet (in my experience this is between € 2.50 and sometimes € 5.50 per day). : S 2.The most beautiful places on campsites are usually without electricity and you are not among the caravans and campers;) 3.It is just very easy and convenient (no mess with (extension) cords anymore) B)
Thanks for Joey’s review. He have some Lensun slar panels, a 80w flexible solar panel installed on the FJ hood, a 100w foldable solar panel and a 10W solar phone charge, the following is his review of these solar panels.
“I have used many products made by Lensun. I have an 80W flexible mounted to my FJ Cruiser that charges my second battery which powers my fridge/freezer and keeps it going. I also have the 100W folding all weather solar charger which charges the batteries on my off-road trailer giving me lighting, charging station for cell phones, Garmin and water pumps. I recently have acquired their folding 10w cell phone charger.
Their products are high quality. The charge is excellent. They withstand any weather you throw at them and they will last for many years. I highly recommend their products and will not consider another brand now that I have had such a good experience with the company and their products.”
The following article is from Joey’s website, about why he installed solar panel on his Toyota FJ and how he did it. (original link http://brox4.com/2018/10/16/overlanding-with-solar-power/)
Overlanding with Solar Power
As I was driving down the road with the sunlight beaming down upon my rig, I couldn’t help but think how I could be harnessing some of this energy and transforming it into power in order to be able to go out in the middle of nowhere and camp where I want to, without having to PAY for an electrical site at some park somewhere. The whole goal and idea of overlanding to me was to get out where there is nobody and see things that most people do not see and do things that most people are not able to do.
If we just go from park to park we are seeing the norm, what everyone else sees and does and we really do not get to experience overlanding to the fullest. We are just park hoppers. So I wanted to make myself as self-sufficient as possible, being able to survive comfortably without the need for outside intervention for periods of time.
So there are several things to consider. Water was my first one. I have to have a shower. I have to be able to drink, brush my teeth, clean clothes and dishes. Power was the next one. As some of us here may be backpackers where we can put everything we need on our backs, we are here to speak of the overlanding experience. So we all have a vehicle of some kind. That vehicle has a battery and plug ins where we are able to charge everything we can think of in one way or another.
BUT, the last thing we want to do is to spend 3 days out in the middle of nowhere, reaching that destination of “going where no man has gone before” and living life without any interference of human resources and then we go to pack up and our vehicle will not start because we have drained the battery down to nothing from charging all of our necessities. So how do we keep from this? What are our options?
So back to my original thought while driving down the road, thinking about these things, and wondering what do I need to do to be able to be completely self-sufficient power-wise and harness this energy so that I can power all the things I have at my disposal in order to be a comfortable as possible and enjoy this overlanding experience to the fullest?
I considered and began to research solar. I had experience with solar before. I have backpacked and I had the small solar charger that clipped onto my pack and as I hiked across the earth, the sun would beam down giving it a charge and then I could throughout the day keep my GPS or cell phone charged. What I needed now was on a much bigger scale. But I still like the idea…
The solar power’s benefits are out there and hold true for most people.
1. It gives us freedom to get out where most people are not able to go. 2. It is quiet. I like quiet. One of the main reasons I want to get away is to get away from the noise I have to deal with every day. 3. It is easy. It requires very little maintenance and no fuel. 4. Even though there is cost to purchase, if you live long enough and go out enough you will eventually make that money back in savings.
Before you get into “is solar right for me?” or “should I use a generator?” you need to determine the answers to a few questions.
1. How often am I going to be doing this? Am I going to be full-time, a couple times a year, multiple times a year? 2. How long am I going to stay at a time? What is the longest I am going to stay without having contact with civilization? 3. What gear do I need to run? Lights, fridge/freezer, fan, charging cell phones and games (and other stuff we should leave at home because we do this to get away from regular life) 4. Noise…some people do not like noise. In the middle of nowhere and you are sitting by the fire at night and you are either listening to the coyotes, crickets and owls and other night crawlers, or you’re listening to a Briggs and Stratton purr on all cylinders. 5. How much do I want to spend? Almost everyone has a budget. Unless you are independently wealthy, you have so much money you have budgeted for each item you want to put into your build according to necessity and need. WANT has a little to do with it if you are into how “cool” or “impressive” your rig is going to be to others. But don’t build your rig so “cool” that you have to get jumpstarted every time your group gets ready to leave because you run everything off of your single car battery.
Is it for me?
1. Weekend Warrior – A couple times a year for weekends. You are really a weekend warrior. There is nothing wrong with that. People joke and kid about you but you get out when you can. We can only do what we can WHEN we can and you take every opportunity to make the best of the time you have. 2. Solar is probably not going to be a big deal to you and it could take years to recoup your investment in a solar power system for your rig. (1) You can most likely keep all of your food in a cooler and there is no need for a fridge/freezer. (2) You can keep your devices (cell phone, tablets, GPS, etc.) charged via your 12v car charger ports. (3) Your lights can run off of batteries. 3. But what you might want to look into is: (1) Rechargeable or solar things such as lights and lanterns (2) Solar lighting around the camp
4. Overlander or Boondocker – If you plan to go out quite frequently or if this is your “thing” in life and what you love to do and you see yourself not only going out when you can get off work on the weekends, and maybe you plan some vacations that will include getting “off grid” for several days or weeks at a time, solar would be beneficial for you. Staying in parks that charge $15-30 a night would add up quickly. Most parks offer spots with hookups and then spots that are labeled as “tent camping” or “primitive.” There is a big difference in price per night if you have to have electricity and water.
5. What you need to look into is: (1) Rechargeable or solar lights and lanterns (for example the collapsible solar lights or LUCI lights ($20 each at Amazon.com) or the AAA battery powered lights offered by ENO which are $20 for a whole string of 10’ (2) Solar panels (many different varieties, sizes, wattages and mounts) like those found from Lensun Solar ( http://www.lensunsolar.com/) (3) Dual Battery System for your rig that can be charged by your solar panels (4) Solar Generator or “Portable Power” such as those offered by Goal Zero in many different options.
Compared to those people who spend $50k to 250k on an RV and then $30-50 a night in a full service campsite (I often think how in the world they can afford some of these rigs), we really do not have that much invested. But to us who work day to day jobs and live paycheck to paycheck it’s a small fortune. And if most of our wives found out just how much we had in our rigs we would be calling a lawyer instead of 4 Wheel Parts for our next purchase.
But we must decide if Solar Power makes sense for us. It’s kind of like sushi, it’s not for everybody. But for some of us, it is really a necessity and will make it where we can bring and enjoy many of the comforts of home and not need any outside sources to do so.
Basic Parts of an Overland Solar System
1. Solar Panels (1) Solar panels come in various sizes and wattage. You can get them from a small wallet size all the way up to 3’x5’ (2) Wattage will depend upon size and can range from 5W up to 100W and several panels can be coupled together to increase wattage. 2. Make Up (1 ) Polycrystalline – most popular and the best price (2) Monocrystalline – more efficient but higher priced (3) TFSC – Thin Film Solar Cell – less efficient but can be made into different shapes. 3. Charge Controller (1) A charge controller sits between an energy source (panels) and the place where the energy is stored (battery or power source). (2) The controller prevents overcharging by limiting the amount and rate of charge to your batteries and protects against drainage by shutting down if stored power falls below 50 percent capacity. 4. Inverter (1) This turns the low-wattage DC power produced by Solar Panels and stored in batteries into AC power. (2) Power Station – this is much like a generator but solar charged batteries power your equipment and supplies. The Power Station is hooked directly to the solar panels which charge the power station. Then you can use the power station as a generator. 5. Storage (1) Vehicle Battery or 2nd battery (2) Power Source
Example Solar Panel Systems & Costs
System Number of Panels Watts Charge Controller Inverter Price
Renogy 200W 2 200W 30 Amp Renogy N/A $464
Lensun 80W 1 80W Lensun 10A N/A $209
GoPower Electric 1 170W 30A GoPower 1500W $1600
Windy Nation 200 2 200W 30A P30L 1500W $533
Zamp Solar 480W 3 480W 30A Zamp N/A $2000
Goal Zero 150 1 Folding 150W N/A Yeti 150 $449
NOTE – The Goal Zero kit listed last would not be connected directly to your vehicle power source but to the Yeti 150 Power Station.
Ok, so let’s go back to 7th grade and put all of this into a word problem and try and make this make sense and see if it is worth it to us. When thinking about energy savings of going solar, we must think in terms of whether it would be comparable to what we would spend using a gas generator. This is totally ruling out the sound co-efficient and just crunching numbers.
An Average generator burned one ½ gallon of gas per hour. If we round around and say that the average price of gas is $2.50 then being parked for 8 (normal time we would run it at night for lights and fans) hours we would spend $10 per night.
Based on that figure, if you have $1000 investment that you have made on solar, you would reach a breaking even point on that investment in 100 days. So how many days per year do you go out and need this type of charging system? If your solar system allows you to avoid $40-50 per night campground fees, then your break-even point would come much sooner.
After you reach that break-even point then your energy costs would be $0, other than what you would pay for replacement or broken parts such as batteries.
Powerbrick100 Lithium Ion 10.2×6.6×8.3 30kgs 12V $725
Smart Battery Lithium Ion 12.8×6.5×8.7 28kgs 12V $1300
I researched and looked around to see what was best to fit my needs. To be honest I put more investing into this presentation than I did my research back then but I think I made the right choice and it has been worth every penny.
I spent $200 on Ebay for the Lensun 80W solar Combo that came with a charge controller. I like Ebay because sometimes they run discount codes pretty often. I wasn’t in a hurry so I waited on the 15% off day. It was a flexible panel that is black and came with all of the cables needed to hook it up to a second battery. I planned to install the panel permanently on the hood of my FJ Cruiser where I had painted the hood black. It was the perfect size and would hardly be noticeable. I also purchased a Heavy Duty Dual Battery Auxiliary Isolator with 15’ and 4’ cables for $112 on Ebay. This is a necessity when using dual batteries and came with the heavy duty cables that I needed to hook everything together.
I went to the local HS welding shop and had them fabricate me a battery stand out of heavy metal. They measured and it took them about 30 minutes to come up with a stand with rails that would fit directly into the slot I had made for it behind my air cleaner, passenger side by the fire wall. They charged me $5 for the materials.
I bought 4 grade 8 bolts at the local Ace Hardware store for $6 with lock washers and washers in order to install the battery plate. This took about 30 minutes to drill the holes, insert the bolts and install. After this I went down to the local Advanced Auto Parts store and purchased their deep cycle battery for $109 and a battery holder for $9. I installed the battery and holder in about 10 minutes and tightened everything down.
I installed the isolator on the driver side and ran wires connecting it to the second battery and also to the alternator. A switch was installed inside the cab for me to push if I wanted to use the alternator to charge the second battery. Otherwise all of the charge would come from it sitting using the solar panel.
I had to purchase windshield water relocators because the solar panel being added to the hood covered up the OEM windshield washers. These were $8 at advanced. I used heavy duty double-sided tape and 4 self-tapping screws to attach my solar panel to the hood. I used double sided tape to attach the charge controller to the top of my sealed intake and ran wires from the solar panel and 2nd battery to the charge controller. It was done.
Total Cost – $435
I added up that I will spend (estimated) 60 days/nights in my tent this year. With an average of $10 per night running a generator the cost would be $600 for an 8-hour night plus the cost of a generator (around $800) totaling $1400. That leaves me with after 1 year a savings of $965 not counting the cost of staying in parks where it would cost an average of $40 per night.
If any question or advice, Please contact us or call us in the following information from Mondays to Fridays. Any wholesale request just call us or email us, thanks.
Contact information www.lensunsolar.com Tel: UK +44 2032875806 US +1 (323) 2845027 China: +86 15759769602 Whatsapp/Wechat: +86 15759769602 Skype: lensunsolar Email: firstname.lastname@example.org, email@example.com
In the past year, Lensun has updated all flexible solar panels and folded solar panels to the latest and most efficient(21.5-22.5%) PERC solar cells. Lensun use PERC 5BB 156.75×156.75 and 158.75×158.75 Solar cells.
(Lensun 100W ETFE Black flexible solar panel made of PERC 5-Busbar 158.75×158.75 solar cells)
But most customers don’t know what PERC solar cell and PERC solar cell are difference from conventional solar cells. A summary of key information is prepared to understand the PERC solar cell.
PERC Solar Cell Features
1. Outstanding surface quality.
2. Advanced diffusion technique ensuring the homogeneity of energy conversion efficiency of the cell.
3. Advanced PECVD film forming, providing a dark blue silicon nitride anti-reflection film of homogenous color and attractive appearance.
4. High quality metal paste for back surface and electrode, ensuring good conductivity, high pulling strength and ease of soldering.
5. Efficiency-increasing 4-busbar and 5-busbar technology that optimises electricity collection and ensures optimal electricity yield from your system.
6. First-rate efficiencies and superlative output consistency.
7. Excellent anti-PID performance (under the following conditions: 60°C, 85% humidity, -1000V, 96 hours).
8. Lower power loss through encapsulation. Appropriate electrical performance parameters (high voltage and low voltage). Current evaluation and positive tolerance for the cell performance compensation guarantee a very low loss from cells to modules.
9. Outstanding solderability. Application of double-printing technology in production improves solderability.
10. Meticulous tolerance and quality checks guarantee a constantly high solar cell output capability and the resultant excellent quality of solar modules.
What does PERC mean?
Literally, it stands for Passivated Emitter and Rear Cell. You also find the term Passivated Emitter and Rear Contact.
What is it?
PERC cell technology defines a solar cell architecture that differs from the standard cell architecture that has been in use for three decades and that is usually featured in all photovoltaic manuals.
Standard Solar Cells
As of today, the vast majority of crystalline solar cells produced follow the structure presented hereunder. The standard solar cell makes up around 80% of the world market
From top to rear:
– screen printed silver paste to form the contacts
– Anti Reflective Coating
– phosphorous diffused, boron doped silicon wafers that form the P-N junction
– aluminum Back Surface Field (Al-BSF)
– screen printed aluminum paste
PERC Solar Cells
PERC, which stands for Passivated Emitter and Rear Cell or Passivated Emitter and Rear Contact, is a new technology aimed to achieve higher energy conversion efficiency by adding a dielectric passivation layer on the rear of the cell.
The structure of a PERC solar cell from front to rear:
– Screen-printed Silver paste front contact
– Anti-Reflective Coating (ARC)
– Silicon wafers that form the P-N junction
– Local Aluminum Back Surface Field (Al-BSF)
– Dielectric passivation layer
– SiNx Capping Layer
– Screen-printed Aluminum paste layer
The dielectric passivation layer contributes to the increase of efficiency by:
– Reducing electron recombination – electron recombination blocks the free flow of electrons through the cell, reducing efficiency. The extra passivation layer makes the flow of electrons more steady and consistent thereby producing additional electric current.
– Increasing the solar cell’s ability to capture light – unabsorbed light is reflected by the passivation layer back to the solar cell for a second absorption attempt to produce additional energy making the cells more efficient.
– Reflecting specific wavelengths that normally generate heat out of the solar cells – certain wavelengths are absorbed by the rear layer of the solar cell accumulating heat and reducing efficiency. The additional passivation layer reflects these wavelengths out of the solar cell maintaining the temperature of the solar cell.
PERC solar cell technology is more straightforward as they only differ slightly from the standard solar cells. It is also more cost-effective as it allows energy output to be maximized due to more efficient energy conversion.
Monocrystalline solar cell 6” (156.75 x 156.75), 4BB (4-busbar) and 5BB (5-busbar)
Click link to buy Lensun PERC flexible solar panel
Lensun New 100W 12V ETFE Flexible Solar Panel with Fiberglass back sheet which is much stronger than the White PET back sheet. Made of Newest Hightest Efficiency 21.5% 158.75 x 158.75mm Grade A Mono Solar Cell