Several of our customers have recently attached their semi-flexible solar panels using nuts and bolts.
Here is what they did:
1. Place the solar panel on the canvas and mark the grommet holes on the canvas.
2. Glue a vinyl disk about 2 inches in diameter to the underside of the canvas at points where attaching bolts will be placed.
3. Puncture a hole in the fabric through the vinyl.
4. Place a 1 inch diameter or greater plastic or stainless fender washer on a 10-24 or similar stainless bolt and pass it through the canvas.
5. Place another fender washer on the bolt on top of the canvas and secure with a nut.
At this point, you have a reinforced canvas sandwiched between two fender washers.
6. Pass the bolt through the solar panel grommet and secure with an acorn nut.
7. Repeat for each solar panel grommet.
See diagram below for details.
On the installation shown above, the solar wires were run through the channel used to attach the canvas to the frame thus hiding most of the wiring.
The excellent performance of our semi-flexible solar panels is opening up new ways to easily implement solar systems on cruising boats. There are several ways to attach our flexible solar panels to a canvas bimini top. Here are some creative ideas our customers have implemented:
1. Zipper solar panels directly to the bimini canvas - Stitch zippers along the sides of the solar panel using an industrial sewing machine. Stitch the mating zipper onto the bimini top with a flap to cover the zipper to protect it from UV rays. Zip the panel onto the bimini and run the wires as necessary. See picture to the right.
2. Attach solar panels to canvas and zipper canvas to the bimini canvas - Panels can be attached to a piece of canvas using zippers, snaps or grommets. Sleeves can be sewn into canvas to hide and protect the wires. The canvas with the solar panels can then be attached to the bimini canvas using zippers.
3. Attach solar panels to the bimini canvas using snaps or grommets - Our flexible solar panels come with 4 or 6 sets of grommets installed. These grommets can be used to stitch the panels directly to the bimini canvas. Alternatively, these grommets can be drilled out and replaced with snaps. The mating snaps can be installed in the bimini canvas so the panels can be simply be snapped into place.
4. Attach solar panels to the bimini canvas using outdoor Velcro (hook and loop) - Stitch or glue the Velcro to the back of the panel and stitch the mating Velcro to the bimini canvas. Panels can be easily removed for storage.
Note: Because the PV cells of the panels are black, they will absorb and radiate considerable heat. Some customers have inserted insulation between the panel and the canvas to reduce the radiated heat. They have used the bubble wrap encased in silver foil insulation available at most home improvement stores. It is about 5/16" thick.
When our supplier told me they had a new high output marine solar panel that was flexible I was skeptical. The specifications seemed just to good to be true. So I ordered some to test. Well, I was pleasantly surprised.
These panels are very well constructed and they have a power generation comparable to our hard panels. These panels can be flexed to 30 degrees so can conform to most boat curved surfaces. The 100+ watt panels have an electrical box on the front (not shown in the picture) which contains two blocking diodes. The 50 watt panel has one blocking diode. The base material is very sturdy and strong. Each panel has grommets for attaching the panel.
I have tested the output of these panels under various weather conditions and their susceptibility to shading. Below is a quick comparison of output of our three mid-range panels laying flat at mid day on a mostly sunny day measured with a meter:
Flexible 100 watt Rigid 105 watt Rigid 100 watt
Monocrystalline Monocrystalline Polycrystalline
Short Circuit Current (Isc) 5.48 amps 5.50 amps 5.26 amps
Open Circuit Voltage (Voc) 19.2 volts 19.7 volts 20.5 volts
Computed Power (not rated power) 105 watts 108 watts 108 watts
Additional information is available on our solar panel page.
Thomas Trimmer has been cruising with his Ericson 38 sailboat on the Great Lakes for over 20 years. He has pioneered the use of solar energy for wilderness cruising. He is continually designing and building equipment to simplify and enhance the cruising experience.