By Cecil Hoge, President of Sea Eagle Boats, Inc.
Several years ago I wrote a blog story called, “My Solar Power Dream”. In it, I outlined my efforts to create a solar-powered boat that really worked. That experiment was more dream than reality. Today, I can say that we are now selling a dream come true – see the picture of the Sea Eagle FishSkiff 16 below.
In my first testing of a Sea Eagle boat with a solar panel and an electric motor, I had put a solar panel on an inflatable sailing catamaran and hooked it up to a lithium battery that powered a Torqeedo electric motor. In the years leading up to that experiment, I had tried a number of solar panels to charge 12 volt batteries, most of which did very little. They were called “Trickle Charge” solar panels and that was a good name because the charge literally had to trickle for several weeks before it actually fully charged the battery. And sometimes, when the panel actually fully charged a battery, it kept going, literally burning holes in my dock. Not a pretty sight.
On my sailing catamaran, I hooked up a PowerFilm® solar panel on the bow between the 2 pontoons with the Torqeedo electric motor at the stern. It worked, but it had a number of problems.
Now this panel was the same size as the larger panel shown in the first picture. It was made from a flexible film imprinted on a strong polyester fabric. It could rolled up when not used, but it was about 3 times the size of the semi-flexible panel shown in the second picture above. The new Semi-flexible Solar Panel that PowerFilm has now developed is flexible, but it cannot be rolled. It is about 1/8″ thick and measures 17″ x 30″. That is far smaller than the flexible panel that measured 34″ x 54″. Then there is the little matter of cost. When we sold the larger flexible panel we had to sell it for $999. while the new smaller panel sells for $369. Last and really the most important features of the new smaller panel was the fact that it had a built-in solar controller which prevented it from over-charging a battery. Trust me, you do not want a battery burning through your dock or your boat, for that matter.
On the sailing catamaran, the larger, more flexible solar panel drooped between the inflatable pontoons. This tended to scoop up water when sailing and hang loosely between the two pontoons. Nevertheless, it did work…kind of. The solar panel did re-charge the battery in the Torqeedo motor, but it took quite a bit of time. If there was sun, it would actually charge the battery fully in about 8 hours, which was pretty good.
But, there were two problems with that:
1. You generally did not get a full 8 hours of sunshine each day.
2. The battery in the Torqeedo motor I was using only held a limited amount of electrical power. It did have, however, a built-in solar charge controller which prevented the solar panel from over-charging. That was helpful, but the amount of wattage in the battery was very limited, meaning the amount of running time was also very limited.
Even when fully charged, the Torqeedo battery could only be run for about 25 minutes at full speed. This meant I could go out fairly regularly, but you had to watch your time and how fast you were going because if you wanted to go fast, you would run out of juice pretty quick. And paddling a 16′ inflatable catamaran back to my home one or two miles away was not something I really wanted to do.
I will say that Torqeedo has now resolved their battery size issue with their new Torqeedo 1003c motor which we now sell. It has a battery that holds double the amount of wattage so the run time is effectively doubled. Even so, you still have to monitor your charge level carefully in a Torqeedo (that is easy in a Torqeedo because of the power level monitor on the tiller arm) because it is also more powerful and it uses up wattage far faster than a smaller electrical motor like our WaterSnake Venom 34.
About 18 months ago I began working on a new kind of fishing boat. It was a fishing skiff designed to hold up to a 6 hp outboard gas motor and 2 fishermen. Our name for this new model is, appropriately, the FishSkiff 16. The first prototype, shown directly above and in the top picture, was 14′ long and 54″ wide. When I conceived this new model I had no intentions to create a solar-powered version of it. I was looking to create a fishing boat that weighed very little, packed up in a car trunk and motored long distances with small, lightweight gas-powered outboards.
When I got the first prototype, I found out that the first prototype did not motor well with a 6 hp outboard. That was because the pontoons were not long enough behind the transom – take a look at the picture above and compare it to the picture below. The problem was that the bow of the boat wanted to ride up at a 20-degree angle at full speed. I can only blame myself for this error since I was the guy who made the drawing of what I wanted our supplier to make. Correcting this problem was simple – all we needed to do was extend the length of the pontoons and provide more buoyancy behind the motor. And that is what we did.
The longer pontoons behind the boat worked great and looked great. I would note that I also changed the shape of the bow and added a rubbing strake on the side pontoons to give this boat a more pointed elegant shape with the drop stitch bow pontoons extending beyond the drop stitch floor. Again, you can see these changes if you compare the wo pictures directly above.
There was just one problem – I still had the first prototype – what was I going to do with that? That gave me the idea to use that prototype with an electric motor and a solar panel. With a small electric motor, there would be no problem with the shorter pontoons. And that was easy because we had already started selling WaterSnake electric motors three years ago – so I had the motors. In addition, I had developed a working relationship with a solar panel company, PowerFilm®, and they had just finished working on a new kind of solar panel which was smaller and more efficient. Finally, I had also developed a relationship with a lithium battery company, Relion Battery.
The main difference of this new kind of PowerFilm® solar panel was that it was about one-third of the size of the original panel, it was specifically designed to charge 12 volt marine batteries and it had built-in solar controller to prevent the possibility of overcharging a 12 volt battery. So I put the new PowerFilm® Solar Panel on one of our Sun/Rain Canopies (where it was out of the way and took up almost no space) and hooked it up to a 50 amp Lithium battery from Relion Battery.
I will note here that I could have used a regular 12-volt lead acid battery, but I liked the idea of the lithium battery because it weighed only 15 lbs. That compares to a 50 amp lead acid battery that generally weighs 50 lbs. to 60 lbs. As an older man, I really liked the idea of a lightweight 12-volt battery. Lithium has some other advantages that are important to mention here. They can be run down completely with virtually no damage or degradation to the power of the battery. Whereas if you rundown a 12 volt lead acid battery by more than 50% you effectively lose about 50% of the useful life of the battery immediately. In addition, lithium batteries can be charged thousands of times with almost no degradation of the power. Lead acid batteries can be charged a few hundred times and a loss of useful power that the battery retains.
So I put the solar panel on one of our large Sun/Rain Canopies (which of course we already had) and hooked it up with a 12-volt controller to the lithium battery and Voila…I had a solar powered FishSkiff.
That is not quite accurate. This new boat configuration was not truly a solar-powered FishSkiff. What was actually happening was that the solar panel was charging the battery whenever it began to run down (provided there was sunshine). And the battery would power the electric motor whenever I took the boat out for a spin.
Effectively, I did have a solar-powered boat because whenever I chose to go motoring I had plenty of juice to cruise around for several hours. Now, this kind of system does have some logistical limits. If you go full speed for over an hour and a half, you could run out of power. And then you would have to paddle your way from there until the solar power put in enough juice to resume motoring or until you got home. A better alternative to that is simply to go at a little slower speed (I recommend 3 mph instead 4 mph) and have all the power you need.
And effectively, whenever I went out, I had all the power I needed, primarily because I generally never would go out for more than 3 hours at a time and, if I did, all that I had to do was slow down a bit and run at half throttle. Since the top speed of the boat at full throttle was 4 mph and the speed of the boat at half throttle was 3 mph, slowing down really was not much of a sacrifice. But running the electric motor at half throttle only used half of the power that full throttle used, so effectively it meant you had a lot more time of the water.
I used this boat for over 6 months last year and I found that I could go boating 5 or 6 times a week without ever having to recharge the battery. The 45w Semi-Flexible Solar Panel from PowerFilm® seems to fully charge the Relion® 50 amp lithium battery in less than 8 hours, that is, presuming there was sunlight.
In summary, I can truly say that our FishSkiff 16, when rigged with our little WaterSnake electric motor and with a new PowerFilm® solar panel can be motored pretty much every day without ever having to recharge the battery.
That truly is A Solar Powered Dream come true!
Should you want additional Information on outfitting one of our Sea Eagle boats with a solar panel, click on the link in this sentence.
Please note, if you are getting a Solar Panel set for one of our boats, you will either want to strap it directly to one of our kayaks or FishSUPs, as shown above, or mount it on a Sun/Rain Canopy as shown on the Sea Eagle FishSkiff 16. If you want to put it on the Sun/Rain Canopy, please let Jerry, in our tech department, know so he can make sure the canopy has attachment grommets in place for the solar panel.
The following Sea Eagle boats take both our canopy and can be used with an electric motor up to 65 lbs. thrust – FSK16, SE9, STS10, 285fpb, 375fc & 10.6sr.
Should you have questions on how to do that, call Jerry at 1-800-473-7308 9am-5pm, EST.