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Recommended Products to Complete Your SunPower Solar System

SunPower E-Flex solar panels
SunPower marine flex solar
flex solar panels for boats
battery BB 100ah.jpg

SunPower panel(s)

MPPT charge


Circuit breaker

Battery bank

SunPower® solar panels are the first step in going solar on your yacht.  Some of the items listed below will be required for installation and to complete your solar system, especially if you are using more than one panel.  Whether you are new to solar, or upgrading your current system aboard, we recommend the following products that are available to complete your install.  We did all the research and made it easy for you to just click on the product and add it to your cart to build your new SunPower system aboard.

Y-Branch MC4 Connectors

For parallel wiring - we highly recommend a variation of these Y-branch connectors.  When connecting your panels in parallel they serve to simplify your wire runs, ease installation and provide a good connection and have a weatherproof seal (IP67) to withstand the outside elements.  They are each sold in pairs and are very easy to connect together (plug and play) and depending on your preferred wiring run the first three options give you more flexibility for connections.  eg. If bringing 4 panels together will the wires on your panel each reach the Y branch connector?  Maybe you will need an extension cable?

Sun Powered Yachts

For 2 panels

2x12AWG to 1x12AWG

Sun Powered Yachts

For 2 panels

Sun Powered Yachts

For 3 panels

3x12AWG to 1x12AWG

Sun Powered Yachts

For 3 panels

Sun Powered Yachts

For 4 panels

4x12AWG to 1x10AWG

Sun Powered Yachts

For 4 panels

The design of the MC4 connectors is that they cannot be accidentally disconnected.  To disconnect and stow your SunPower® E-Flex panels, you will need one of these tools.  Note: do not connect or disconnect panels when exposed to light (under load).  Only connect or disconnect when the panel is completely covered by a dark material.  This tool can also be used when attaching your own MC4 connectors to PV wire.

Note: not all MC4 disconnect tools you see online are the same size!  The 'prongs' may be too large to fit but this tool from TE Connectivity will fit all SunPower® E-Flex panels.

Sun Powered Yachts

sold as a pair

PV Extension Cable

Each install will be different from the next but you will likely need an extension cable to go from your solar panels/Y branch connectors to the MPPT charge controller (which should be as close to your house battery bank as possible). 

Each wire run will be different and if you are comfortable cutting wire, crimping and adding your own MC4 connectors then one option is buy a roll of PV wire some MC4 connectors and a crimping tool.  To make it more convenient there are PV extension cables with MC4 connectors already attached (male on one end & female on the other)  When choosing the right size of wire, make sure to consider both voltage drop and amps.  Most installs will use 10AWG  wiring to ensure that you harness all of the solar output.  It is important that the maximum number of amps from your panels does not exceed that of the wiring. 


As a general rule 10AWG is for up to 30 amps BUT it is very important to look at the distance of your wire run.

For example: I have a 20ft wire run from my Y branch connectors to my MPPT charge controller.  Take the 40ft extension cable and cut the cable halfway. I now have 2x20ft extension cables with a male and female MC4 connector at one end and bare wire at the other.   The MC4 connectors will connect to your Y-branch connector (for parallel wiring) or to your panels (for series wiring) and the bare wire ends will connect to your MPPT charge controller input. 


Note: measure your wire run accurately as you will be surprised it is likely further than you first thought.  When we installed a panel on a Dufour 382 the wire run was right on 30ft, a 60ft extension cable was only just enough.  

Sun Powered Yachts

10AWG PV extension wire
3ft - 120ft

Extension cable from my panel to my Y branch connector - Another thing to consider is that maybe your panels will not all reach your Y-branch connectors (for parallel) or might not reach your other panels (for series) In which case you will need an extension cable but it will likely need to be a shorter length and you won't need to cut it in half (as you will need an MC4 connector on each end).

MPPT Charge Controllers

MPPT Charge controllers are an integral part of your solar system aboard your yacht and serve to control the flow of power from the solar panels to the battery bank.  SunPower® E-Flex panels work best with MPPT (Maximum Power Point Tracking) charge controllers as opposed to PWM (Pulse Width Modulation) charge controllers. 


See our blog and FAQ for more info on MPPT but in short the innovative technology in the MPPT controller serves to maximize your power production and battery charging.  MPPT charges your batteries up to 30% faster than PWM regulators – with the same number of panels and as such are highly recommended for your solar system. 

There are a number of brands available to choose from but we recommend Victron Energy MPPT controllers.

'Buck' or 'Boost'

It's first important to decide if you need a 'buck' or 'boost' MPPT charge controller which depends on the voltage of your solar panel(s) and the voltage of the battery bank.


A buck MPPT charge controller will take a higher voltage from the solar panel(s) and reduce (buck) the voltage to charge your battery bank eg. 1x170W panel is rated at 29.4V and you are charging a nominal 12V battery bank so you need to buck the voltage.








solar power for boats

29.4V panel


SunPower marine solar panels

'Buck' MPPT

higher voltage panel to lower voltage battery


12V nominal

battery bank


battery BB 100ah.jpg
sailboat solar panels
SunPower marine solar panels
SunPower marine solar panels

A boost MPPT charge controller will take a lower voltage from the solar panel(s) and increase (boost) the voltage to charge your battery bank eg. 1x170W panel is rated at 29.4V and you are charging a nominal 48V battery bank so you need to boost the voltage. 

29.4V panel


'Boost' MPPT

lower voltage panel to higher voltage battery


48V nominal

battery bank


Victron Energy


All of the Victron Energy MPPT Charge controllers in our store are buck controllers, taking your higher voltage panel(s) and reducing (buck) the voltage down to charge your battery bank.


We have had a lot of positive feedback on the line of SmartSolar charge controllers by Victron Energy.  They have Bluetooth built-in which enables set-up and monitoring with a smartphone or tablet.  They also feature, advanced MPPT detection to mitigate shading losses.  Check the voltage of your battery bank and the PV input accepted, these come in 10, 15, 20, 30, 35, 45 & 50Amp output. Victron also offers a wide range of other products like inverters to further complete your SunPower® flexible solar system on your yacht.  

When looking at their products (eg. 75|15) the first number is the maximum solar open circuit voltage (75V) and the second is the max charge current in Amps (15A) - BUT it's very important to check the spec sheet to ensure that your solar panel(s) do not exceed the maximum input parameters of the charge controller.  At best you would be limiting the output potential of the panels, at worst you could damage the controller.

As of January 2015 all Victron Energy products come with a 5 year limited warranty (with the exception of their batteries which have a 2 year limited warranty)  We heard great feedback about their technical support from a number of people who stopped by our booth in Annapolis.  For their full product line you can visit


Notes: There was a Victron Energy BlueSolar range of MPPT charge controllers

without bluetooth built in that has since been discontinued.   


If you want to back up your bluetooth and have the redundancy of a remote

monitor or just like the convenience of a display at the nav station then both

the BlueSolar & SmartSolar MPPT charge controllers have the option to add

a separate remote monitor with display called the MPPT Control 

(select your length of VE.Direct cable)

VictronConnect app

Download the 'VictronConnect' app for free.  When first powering up your charge controller and pairing it with Bluetooth you will likely need a password which is set to six zeros (000000) You can then change this password to one you prefer.  You will also likely have to carry out a few firmware updates, which is pretty straightforward and in no time you will be paired and able to see your solar system performance in great detail.  Historical data is also stored for up to 30 days.




SunPower marine solar panels
SunPower marine solar panels
SunPower marine solar panels
VictronConnect app.png
SmartSolar range
bluetooth connectivity built in

The full range of Victron SmartSolar MPPT controllers is available in our store with free shipping in the USA.  Just click on a controller for more product details and spec sheets. 


We're happy to help you size the correct controller(s) for the number & size of SunPower solar panels you install.  Just email or call us and we'll check the parameters of the panel(s) and controller(s).  

SunPower marine solar panels


PV Input:

12V - Up to 145W

24V - Up to 290W 

36V/48V - N/A

SunPower marine solar panels


PV Input:

12V - Up to 290W

24V - Up to 580W 

48V - Up to 1160W

SunPower marine solar panels


PV Input:

12V - Up to 500W

24V - Up to 1000W

36V - Up to 1500W  

48V - Up to 2000W

SunPower marine solar panels


PV Input:

12V - Up to 220W

24V - Up to 440W 

36V/48V - N/A

SunPower marine solar panels


PV Input:

12V - Up to 220W

24V - Up to 440W 

36/48V - N/A

SunPower marine solar panels


PV Input:

12V - Up to 440W

24V - Up to 880W 

36V/48V - N/A

SunPower marine solar panels


PV Input:

12V - Up to 700W

24V - Up to 1400W 

36V/48V - N/A

SunPower marine solar panels


PV Input:

12V - Up to 650W

24V - Up to 1300W

36V - Up to 1950W 

48V - Up to 2600W

SunPower marine solar panels


PV Input:

12V - Up to 860W

24V - Up to 1720W

36V - Up to 2580W 

48V - Up to 3440W



Do you have a 48V battery bank aboard and wondering how you can charge your batteries with just one solar panel? 

Genasun has the answer.  Their charge controllers are made in the USA and have a 5 year limited warranty. 


Most solar MPPT charge controllers move power from a higher voltage panel to a lower voltage battery bank. The Genasun GVB-series controllers, in contrast, pump electricity uphill. These controllers will take a lower voltage panel and increase (boost) the voltage to charge a 24V, 36V or 48V battery pack.

Check out for the full range of Genasun controllers.  If charging a 24V-48V nominal battery bank, the GVB-8 (Boost) controller is ideal with any SunPower E-Flex panels.

Note: It's important to choose the correct Genasun GVB-8 controller for your battery type - Lead Acid OR Lithium-Ion

genasun controller

Genasun GVB-8  48V

for Lead-Acid batteries

SunPower flex panels

Genasun GVB-8  24V

for Li-ion batteries



Genasun Waterproof (WP) boost charge controllers   

Most charge controllers are designed to be placed inside the boat

in a dry place and so have a low IP rating (IP22).  Genasun has a solution

for controllers that you might need to install in a place more prone to

the elements & likely to get wet or damp. 

Their waterproof boost controllers are rated IP68 and the advanced

electronics inside the controller are encased in a proprietary potting

compound making them ideal for marine applications. 


genasun WP

Circuit Breaker

Bussman 187 Series Marine Circuit Breaker

We recommend installing a circuit breaker after the MPPT charge

controller and before the battery bank (on the positive wire).  This will

allow you to isolate the solar from the battery bank should you need to

work on the batteries.  Match the circuit breaker to the output of the

MPPT charge controller eg. 100|50 pair with a 50A circuit breaker.   

SunPower flex panels

LOXX Fasteners

LOXX Fasteners - An alternative to installing using velcro on a bimini top are the LOXX fasteners.  These high quality, stainless steel fasteners made in Germany allow for quicker removal of the panels.  The variety of upper parts and lower parts even gives options for installing onto hardtops/coachroof.

The full range of LOXX fasteners are available at

sailrite logo

LOXX fasteners used on an install of 2x110W flex panels aboard S/V Delos

an Amel Super Maramu


Don't forget you will need a

LOXX fastener install key to

tighten up the fasteners

LOXX XL upper part with long washer

can attach to the panel

LOXX fasteners for solar panels

Sailrite is actually a great resource for tutorials & learning with their 'How To Guides' both on their website and YouTube Channel.  One example is the video below about LOXX fasteners

Deck fittings


Depending on your installation you will likely need a watertight cable gland for your marine electronic cables to enter through the boat.  This will be the PV extension wires (positive and negative) running from your solar panels down into the boat to the MPPT charge controller.  There are multiple options and sizes of deck fitting available and these are just a few suggestions.  We have had positive feedback on customers that went with Scanstrut & Seaview, also these are regularly available from your local marine chandlery and as such we don't offer any in our store. 


Have an alternative solution that works aboard your boat?  Email us and we'll add it here.  

MC4 dust covers 

Are you taking your solar panels down & stowing them for any period of time?  Use these dust covers made by TE Connectivity to protect the MC4 connectors from any dust/dirt ingress on the panel and also any PV extension wire you have still running that would be exposed to the elements.  Available in our store and sold as two pairs one of these covers will protect the pin (negative connector on the panel) and the other will protect the socket (positive connector on the panel)

SunPower marine solar panels
SunPower marine solar panels
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