Frequently Asked Questions
At Sun Powered Yachts we understand you will likely have some great questions about marine flexible solar panels, the SunPower difference and how you can install a SunPower solar system on your yacht.
We hope that you will have found a lot of great info so far and can also use the FAQ page as a good resource. Scroll down, or click on the search icon and type what you're looking for, to find out more.
(Note: see if we're available on chat to answer your question right away and also check back as we're always adding more FAQs to this page.)
Where can we find you?
Sun Powered Yachts is based on the Big Island of Hawaii and is an Authorized Dealer of SunPower® flexible solar panels and since Feb 2020 SunPower® fixed frame panels also.
We're happy to answer any questions on the phone & email about sailing and going solar aboard your yacht. After a successful launch at the US Sailboat show in Annapolis, October 2018, we have plans to regularly exhibit at a number of other US boatshows.
Unfortunately multiple boatshows have been cancelled in 2020, including the International WorkBoat Show which should have been in New Orleans on December 15-17, 2020.
We're uncertain which boatshows will be going ahead in 2021 but we'll be signing up for as many as we can and are looking forward to being back on the road!
Who is SunPower?
Since 1985, SunPower has been leading global solar innovation. SunPower solar panels consistently deliver more energy and long-term peace of mind with the highest performing solar power systems available. SunPower is the top solar energy choice for homeowners and businesses around the world.
Global headquarters based in Silicon Valley since 1985
Total solar energy generated >18,000,000 megawatt hour (MWh)
Diversified global portfolio leading residential, commercial and utility solar energy markets
World's highest efficiency solar panels featuring SunPower® Maxeon® cell technology
More than 750 patents for solar technology
How long has SunPower been manufacturing flexible solar panels?
SunPower has been designing and manufacturing high efficiency Maxeon™ solar cells for their own residential and commercial panels since 1985. They have been selling these Maxeon™ cells to original equipment manufacturers (OEM) for several years who, to varying degrees of success, have been making their own models of flexible solar panels.
What is the E-Flex Series from SunPower?
The E-Flex Series is currently four variations of flexible solar panel, the 50W, 100W, 110W and 170W models (new March 2019) As always SunPower continues to innovate and develop new products and will be looking to add to the E-Flex Series in the future.
What is the best way for me to stay up to date with all the changes?
Simply submit your email address at the bottom of our home page to receive our e-mail updates. Don't worry we won't be spamming you or selling your data, we just want to let you know about new products in the E-Flex Series, developments in the tariffs imposed on solar imports and other news from the solar & sailing industry.
Is the Junction box waterproof?
What is the difference between monocrystalline and polycrystalline solar cells?
Both monocrystalline and polycrystalline solar panels serve the same function: they capture energy from the sun and turn it into electricity. They are also both made from silicon. To make solar cells for mono-crystalline solar panels, silicon is formed into bars and cut into wafers. These types of panels are called “mono-crystalline” to indicate that the silicon used is single-crystal silicon. Because the cell is composed of a single crystal or ingot, the electrons that generate a flow of electricity have more room to move. As a result, monocrystalline panels are a black hue which is more efficient, and can handle temperature and shade variations better than polycrystalline panels.
Polycrystalline solar panels are also referred to as “multi-crystalline,” or many-crystal silicon because there are many crystals in each cell. There is less freedom for the electrons to move, resulting in lower efficiency ratings than mono-crystalline panels. They may be less expensive, but lower costs results in reduced efficiency and a significantly less durable product than mono crystalline cells.
What does 23% cell efficiency mean?
Solar cell efficiency refers to the portion of energy in the form of sunlight that can be converted via photovoltaics into electricity. Current solar technology at the commercial level only converts electricity with a maximum efficiency of about 25%. This represents the 'ceiling' of panel cell efficiency (Note: higher results have been made in the lab).
SunPower® Maxeon™ Gen II cells (in the 50W & 100W panels) are 23% efficiency
SunPower® Maxeon™ Gen III cells (in the 110W & 170W panels) are 25% efficiency
SunPower makes the most efficient solar cells manufactured today which means more power in less space aboard your yacht!
What is a by-pass diode?
SunPower E-flex solar panels include a by-pass diode inside the junction box to protect your panel. When activated the by-pass diode will limit the total amount of power that can be dissipated by reverse biased cells.
Reverse biase can occur when voltage passing from a non-shaded cell (higher voltage) flows to a shaded cell (lower voltage) and generates heat. A reverse bias cell is essentially consuming power from it's neighbouring cells rather than generating it. The most common cause of reverse bias is partial shading.
SunPower cells are specifically designed with built in by-pass diode protection to maximize efficiency and mitigate the effects of shade on your panels. The cells have a stable reverse-biased breakdown that happens uniformly across the back of the cell. This results in much lower temperatures, prevents the 'hot spot' phenomenon occuring and as such the by-pass diode in the junction box is activated less often. A by-pass diode that is activated less often will last much longer.
Can I easily connect my E-Flex panels together?
What is Light Induced Degradation (LID)?
This is a loss of performance (1-3%) of brand new panels when first exposed to sunlight. Fortunately SunPower® flexible solar panels are NOT effected by LID and as such retain their high levels of performance (efficiency). The simple answer why is that the silicon used in the SunPower® cells is of a different type. SunPower uses n-type silicon and only p-type silicon found in conventional panels is effected by LID as it is boron-doped and suffers from the boron-oxygen effect when first exposed to sunlight. Yet another reason why SunPower is better.
Should I keep my panels clean?
The more sunlight that hits a panel, the more power it generates. Typically panels are self cleaning with normal rainfall. However, on your yacht, they are more prone to bird droppings and a build-up of general dust and dirt that does not wash off with just rain. Therefore, we recommend periodic cleaning of your E-Flex panels with non heated water, mild soap and a soft sponge to wipe the surface clean in a circular motion.
What is an MPPT charge controller?
MPPT stands for Maximum Power Point Tracking. This is to do with the solar charge controller that is highly recommended to have installed between your solar panel(s) and your battery bank. The MPPT charge controller serves to maximise the potential charge (amps) going to your batteries by constantly looking for the 'best' amount of power to provide. It does this by constantly monitoring the stage of charge of your battery bank and the output from your solar panels and adjusting the charge accordingly.
Another way to look at it is that the solar panels produce a higher voltage (18.8V) than the battery requires for charging (12-14V) and so the MPPT controller drops the voltage down and increase the amps. Depending on a number of factors this can increase the efficiency of your panels anywhere from 10-30%.
We have the Victron Energy SmartSolar MPPT charge controllers available in our store. We get a lot of positive feedback from customers that like the built-in bluetooth monitoring. That way from the VictronConnect app on your phone/tablet you can monitor the system in great detail.
Read our news story for more details on "Your MPPT controller & app explained"
Can I recycle my old solar panels?
Can you ship to me outside of the USA?
Can I purchase the SPR-E-FLEX-170 panel in the USA?
The SunPower 170W flexible solar panel is assembled in France and has been available in the USA since March 2019. Order yours now! The 170W panel is subject to the solar import tariff when imported to the USA. This tariff is being placed on solar panels sized from 120W-320W. Read more on the new SunPower 170W from our recent blog post
I have a Watt&Sea, can I connect solar panels to my controller?
Will you ship my panels from Hawaii?
No. To help reduce costs and delivery time our stock of SunPower flexible solar panels is warehoused on the 'mainland' and we offer free shipping throughout the USA (including Alaska, Hawaii & Puerto Rico)
Can I charge my 24V or 48V battery bank with solar?
Yes. Most solar MPPT charge controllers move power from higher voltage solar panel(s) to a lower voltage battery bank. These are called 'buck' controllers and the full range of Victron Energy SmartSolar MPPT charge controllers are 'buck'. So you need to have a solar panel array voltage that is greater than your battery voltage.
What is a conventional solar cell/panel?
What does IBC mean?
How can I calculate Amps?
Watts = Volts x Amps (eg. 100W = 17.1V x 5.9A)
Amps = Watts ÷ Volts (eg. 5.9A = 100W ÷ 17.1V)
Volts = Watts ÷ Amps (eg. 17.1V = 100W ÷ 5.9A)
What does premium cosmetic quality mean?
At Sun Powered Yachts we only sell premium cosmetic quality panels. SunPower has different grades that are given to the finished E-Flex panels: Premium, High & Moderate. It's important to note that cosmetic quality has no effect on power production. In different applications customers may not be as concerned with cosmetic quality (eg. trucking industry)
Are these panels made in China?
What is PayPal Credit?
Can I mix solar panels of a different wattage, eg. 110W and 170W?
Yes you can, BUT it is not ideal and certainly needs more attention and thought before setting up. It is certainly better & recommended to wire together panels from the same manufacturer and the same panel wattage (or wire individual MPPT charge controllers)
What does 'BATT', 'PV' & 'LOAD' mean on my Victron MPPT charge controller?
My electric motor has a high voltage battery bank, can I charge with solar?
Yes. We are confident that we can help you find a solution to charge your battery bank with SunPower solar panels. Some brands of electric motors require higher voltage battery banks eg 96V or 108V and your typical MPPT controller will only go up to 48V. We have worked on a few projects now with Elco and Torqeedo to find a solar charging solution. Please email us and we can help you with your project and in our shop we have a high voltage charge controller manufactured by AERL in Australia.
What are the SunPower E-flex panel warranty details?
No Salt Water Exclusion & Backed by SunPower
Is this a manufacturer's warranty?
Yes. The warranty on the SunPower E-flex solar panels is from SunPower (the manufacturer) not Sun Powered Yachts (authorized dealer).
What is the panel 'nameplate'?
Where can I find my panel serial number?
Each solar panel has a unique serial number that SunPower can use to identify the panel history; date of manufacture, panel testing results etc
What are interconnect tabs?
What does premium cosmetic quality mean?
At Sun Powered Yachts we only sell premium cosmetic quality SunPower E-flex solar panels. SunPower (the manufacturer) grades the finished panel depending on cosmetic quality. For some applications a lower cosmetic quality is acceptable, say the trucking industry, but for marine applications we feel it's best to only sell the premium cosmetic quality.
What size MPPT charge controller do I need?
Have a look at our install page where you will find the range of Victron Energy SmartSolar MPPT charge controllers. Each has a max PV for the input, but it's important to look at some other parameters.
What does 'LINE' and 'LOAD' mean on my Bussman circuit breaker?
Who is ABYC?
ABYC is the American Boat and Yacht Council, a voluntary standards creating body for the marine industry responsible for Standards and Recommended Practices. Visit their website to learn more www.abycinc.org
What is a Bussman Series 187 marine circuit breaker?
A device that, like a fuse, interrupts a current in an electric circuit when the current becomes too high. Unlike a fuse, a circuit breaker can be reset after it has been tripped. When a high current passes through the circuit breaker, the heat it generates, causes a trigger to rapidly separate the pair of contacts that normally conduct the current.
How much power will I get from my panel?
There are more complicated ways to estimate how much power you are likely to get from your panel and performance will vary depending on weather conditions, shading etc. But to keep it simple you can follow this trick to get a potential daily yield in terms of amp hours (for a 12V system):
170W divide by 3 = 56-57 amp hours
What does my free consultation include?
After filling out some details on our website about your project and some key factors about the system you have/plan to have, we can look at which SunPower panel will work best and how many of them, recommend which MPPT solar charge controller to use aswell as the extra items needed to bring the whole solar system together.
With my SmartSolar MPPT controller is the bluetooth always on/transmitting?
The Victron Energy SmartSolar range of MPPT controllers has built-in bluetooth capabilities. The bluetooth is always “active” drawing a very small amount of power and follows standard Bluetooth LE protocol.
After a period of inactivity the bluetooth goes into a low power search mode, less than 1mA. Once an external device queries it for connection (eg. your phone) it wakes up full functions again.
Should you prefer not to have the bluetooth feature then go ahead and choose a BlueSolar MPPT charge controller which has no built-in bluetooth. We don't list these in our shop but we can easily request one and email you an invoice.