Over the past few years we have looked at a lot of solar panel mounting systems, the major problems on canal boats seems to be that the roofs are curved, they are then also covered in vents, ropes and storage for poles, and planks etc.
While we are moving the boat we want as lower profile as possible so we have a good clear view ahead without having to worry about low bridges etc . Our current mooring is near the fearsome M5 tunnel on the Droitwich Canal, which on a bad day, looks like it can scalp anything off the top of your boat.
All the systems we have seen are compromises dependent on the design of your boat, the design/size of your panels and layout of your roof.
Types of Solar Panel Mountings
Flat Mounting systems
Flat solar panel mounting systems are fitted directly to the roof of your boat they are probably suited to boats used in the summer months are the sun is more directly overhead.
These are the simplest to install, the most basic are ABS plastic corner mounts, that are fixed to the panel and directly to the roof. If you have a curved roof you will need mounts that lift the panel at each side high enough to clear the curve of the roof. They are probably best suited to narrow panels along the centre line of the roof.
For long panels additional side mounts are recommended to keep the panels rigidly fixed, the example about is very common, this example comes from Sunworks UK.
There are may other flat style mounting, some are made of aluminium extrusion, but if you have a curved roof you will need to make sure they hold you panel high enough to clear mushroom vents and that dreaded rood curve.
Flat mountsare probably adequate in the summer with the sun overhead, but we planing on staying on our boat all year around so I have been investigating being able to tilt my panels.
NEW – Magnetic Mounts
After I had written this article and while discussing the options on the Canal world forums https://www.canalworld.net/forums I was recommended to look at some Magnetic Mounts by @robtheplod of Project WaterLily these look at an excellent solution and they are available from Bimble Solar.
NEW NEW – Raised and Strengthened Mounts
I found this solar mounting on a boat in our marina, it is home designed by the boat owner, the adjustable feet have a ball joint and are bolted into the roof with a waterproof tape in-between, then an aluminium extrusion runs the length of the panel increasing the mounting hight and also adding signification strength to the panel, that can tend to flex under their own weight.
As you can see a lock nut holds the panel up and another clamps down on the aluminium this enables the hight to be adjusted. The owner also recommended a slight tilt from to back on the panels so that rain water did not collect on the panels.
The panels are then bolted to the aluminium extrusion , there are 6 of these mounting on each panel, making them very secure.
The aluminium extrusions came from Aluminium Droitwich who have a very convenient eBay store and also welcome call 01905 794620 and visitors at Berry Hill Industrial Estate, Droitwich WR9 9AB.
Tilting mounting systems
A lot of the advertised tilted panel systems come from the camper van market where they are often placed on the ground and turned to the best position, most of the ones I have seen and not designed for roof mounting and have a fixed tilt or only tilt to one side, not ideal for mounting on a boat roof.
One of the easiest and most common boat tillable mounting systems are these aluminium triangles, that allow some angle to be set and can adjusted to each side of the roof , while use with thin panels means they can be angled well it is not ideal for wider panel as the width of the panel makes it harder to get the correct and most efficient angles in the autumn , winter and spring (see chart below).
One of my favourite YouTube channels Minimal List modified some mounting to enable them to be used on the curved roof of there boat while also allowing them to be tilted to either site, I initially like this method, but further research and I think I have found and even better solution.
Probably for me so far the ultimate tilting panel mount comes from Midsummer Energy
As you can see these mounts are not worried by the roof curve and have can be set at a very high tilt angle, ideal for all year round use, I have even seen these tilted front to back to a limited amount.
Have a look at a YouTube video from Never Enough Cruising to see them in action
Why tilt your panels
Solar Panels work best when light from the sun hits them at a 90 degree angle, else as the angle gets near to 0 degrees the suns rays are reflected and bounce off the panel and are lost. Effective tilting of the panels can increase efficiency by upto 50%.
Over the year the Sun will be higher in the summer and lower in the sky during winter, using the example of Birmingham, as our boat is moored near there, I created a table of the optimum angles to tilt your solar panels during the day for the best power output.
Note: This could be still improved if you change the angle during the day as the sun is much lower in the sky in the early morning and late afternoon.
| January | 60° |
| February | 57° |
| March | 51° |
| April | 43° |
| May | 33° |
| June | 27° |
| July | 27° |
| August | 33° |
| September | 43° |
| October | 51° |
| November | 57° |
| December | 60° |
Note: Mounting your solar panels and galvanic corrosion
Galvanic corrosion is an electrochemical process where one metal corrodes in preference to another metal when it is in contact with through an electrolyte. The electrolyte is our case is dirty water. The metals are the steel roof and the aluminium solar mountings or the bolts that connect them.
You can minimise this corrosion using a painted finish, or by using non-metalic/rubber washers and or even a layer of sealant, like Sikaflex 291i Marine Adhesive & Sealant works well I am told and will be what I am using to seal/stick down my mounts
Also see
Planning for Solar Panels – Part 1
Planning for Solar Panels Part 2 – Panel Mounting Options
Planning for Solar Panels Part 3 – Types of Panels
Planning for Solar Panels Part 4 – MPPT vs PWM solar controllers
Planning for Solar Panels part 5 – Cable sizes, lengths and resistance.
Planning for Solar Panels part 6 – Panels in Serial or Parallel
Planning for Solar Panels part 7 – Buying the cable and Circuit breakers
Planning for Solar Panels part 8 – Buying Solar Panels and Mountings
Planning for Solar Panels part 9 – Wiring
Planning for Solar Panels part 10 – Drilling, Tapping and Fitting
