120 Watt Shade Tolerant Flexible Solar Panel - Sunpower A+ Grade 24.4% Efficient Cells
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Wiring Diagrams
120 Watt Shade Tolerant Flexible Solar Panel - Sunpower A+ Grade 24.4% Efficient Cells
Power your marine adventures with our 120W shade-tolerant flexible solar panel, ideal for mounting on a bimini, dodger or a curved deck surface. Built with SunPower A+ Grade 24.4% efficient cells (the highest efficiency SunPower solar cells available), this panel delivers top-tier energy output — even when partially shaded by your mast, boom, or onboard equipment.
Each panel is split into four independent quadrants that all operate independently, so if one quadrant is shaded the other three have full power output. Its flexible, lightweight construction makes it easy to mount on uneven surfaces without compromising performance or aesthetics.
Best mounted between support bars to prevent damage to solar cells. Lots more information here.
✅ Includes mounting grommets, MC4 connectors, and blocking diodes for quick, secure setup.
📦 Ships Next Day UPS Ground from Denver or Michigan.
Key Features
⚡ 120 Watts of high-efficiency SunPower A+ Grade cells
☀️ Performs in partial shade — four independent cell quadrants
🧩 Flexible & lightweight — perfect for bimini, dodger, or curved decks
🔋 24.4% cell efficiency for maximum energy output
⚙️ Easy installation with grommets, MC4 connectors & blocking diodes included
🌊 Marine-grade durability – built to withstand saltwater and sun exposure
Specifications
| 120 Watt Flexible Marine Solar Panel | |
|---|---|
| 🔧 Model | CMP23115FX-120-ST |
| ⚡ Rated Power |
120 Watts |
| 🔋 Peak Power Voltage (Vmpp) | 20.5 Volts |
| 🔋 Peak Power Amps (Impp) | 5.9 Amps |
| ⚡ Open Circuit Voltage (Voc) | 24.6 Volts |
| ⚡ Short Circuit Current (Isc) | 6.3 Amps |
| 🌞 Cell Conversion Efficiency | 24.4% |
| 📏 Dimensions | 21.3" x 42.71", 540 x 1085 x 3 mm |
| ⚖️ Weight |
4.6 lbs, 2.1 kg |
| 🧱 Substrate | Anti-cracking materials |
| 🔲 Background Color | White |
| 🧩 Cell Layout | 3 x 12 (12 are half cells) |
| 🛡️ Warranty | 5 years |
🎥 Shade-Tolerant Solar Technology Explained
Learn how CMP’s shade-tolerant wiring design keeps power flowing even when parts of the panel are shaded. This advanced technology ensures reliable solar performance for boats, vans, and off-grid systems, making it ideal for real-world marine conditions where shadows are unavoidable.
I ordered the CMP23115FX-120-ST panel for a special project on my Toyota Tacoma to create an on board solar generator to charge the main battery and a lithium battery. The first panel I received was defective, it generated random voltage and no current so I pretty much chalked it off to the protective diodes in the junction box. I contacted Tom and let him know everything I could tell him without disturbing the sealant in the junction box. He quickly put me in touch with Cindy to arrange a replacement. I have received the replacement and am very impressed with the improvement of quality in the new junction box which has cable restraints and better cable which is easier to work with when installing. The new one also seems to have upgraded solar cells. Guys thank you very much for looking after me in my custom truck generator! Also to everyone else, you’d be taking a chance if you don’t obtain your solar needs from these guys!
Brenon
I did a search for a solar panel system for my Bavaria 35 and Tom's website was the most clear and straightforward website I found. And Tom was extremely helpful in helping analyze my electrical load needs. He put together a great system of semi-flexible panels to be located on my bimini, two 145 watt panels and two 55 watt panels. They work great. I highly recommend Tom and his company, Custom Marine Products.
did just what I wanted; kept the batteries up over the winter
Easy installation and it’s pushed us over the line in sustaining our demands to run the boat’s loads through the day in the Bahamas!
We installed two 155 watt panels, and two 120 watt shade tolerant panels one year ago. These have generated more than enough power to run refrigeration overnight at anchor. The panels are bimini mounted with the shade tolerant versions near the boom. I highly recommend the shade tolerant versions as in practise they perform as well as the higher wattage panels.
Harold Beer, Lansing, MI
March 25, 2025
I bought and installed this unit with Tom's help and advice over email back in 2020 and it has been a huge help ever since. It makes our battery bank seem twice as big and has taken a decent amount of abuse occasionally getting walked on.
Couldn’t be happier.
Our New 4 Quadrant Design
The diagram along side illustrates how these amazing panels work. Instead of the normal 2 quadrant design we use a new split cell design allowing the panel to have four quadrants of solar cells linked in series and isolated with inner panel blocking diodes. If one or two quadrants are shaded, the other quadrants perform at normal output. This can increase shaded panel output by 3 times that of a standard shaded panel.
SunPower Maxeon Shade Tolerant Series
Solar panel shading is a major issue on many boats. Shading can reduce a standard panel performance by over 60%. Custom Marine Products has developed a series of semi-flexible shade tolerant solar panels that have superior performance when partially shaded by boat equipment or nearby objects. These solar panels have high performance SunPower Maxeon cells. The diagram to the left illustrates how these amazing panels work.The junction box is mounted in the center or the edge of the panel enabling the panel to have four quadrants of solar cells linked in series and isolated with diodes. If one or two quadrants are shaded, the other quadrants perform at normal output. The result is a panel that will provide up to three times the output of a standard panel when shaded. These shade tolerant panels are ideal for bimini and dodger mounting where there is boom, mast and instrument pole shading. Patent pending
What Makes Our Panels Superior
- Our Semi Flexible Shade Tolerant Panels use only SunPower Maxeon A+ Cells.
- The SunPower cells we use in these panels are 24.4% efficient.
- We use an ETFE laminate coating that won't delaminate or go milky for 10 years.
- The ETFE laminate is applied with a prismatic finish to direct sun energy into the cells.
- Panels use internal blocking diodes to isolate the quadrants unaffected by shading.
- We build 4-6 grommets into the panels edges for easy installation with our mounting kits.
- All panels come with 3 foot pigtails and MC4 connectors.
- Our junction boxes are filled with Non Gassing Silicon RTV for maximum electrical waterproof insulation and corrosion resistance.
Solar System Design and Installation
We have put together a collection of helpful information for our customers on everything to help you design you perfect system and installation instructions.
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CMPower Shade Tolerant Solar Panels for Marine Applications
CMPower’s shade tolerant solar panels featuring premium SunPower Maxeon cells and innovative wiring design.
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Shipping
Products ship the day after payment (domestic).
- Free shipping on orders over $1,500 (Lower 48 US states).
- $65 flat-rate shipping for orders between $500–$1,499 (Lower 48).
- International shipping takes longer. No tariff charges added — call for pricing.
Custom Designs & Custom Made Panels Available on Request
Our engineers will work with you to design a solar system specific to your needs including Lithium Batteries if you like. (Batteries are 10% off w/ solar system purchase).
If you'd like a custom solar panel, we can do it at $10/watt, more info here: Custom Solar Panels
Call Us: 248-712-1526
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