I thought I’d do a quick post on an idea I’m working on to generate some power to charge the batteries. Our main one will be solar panels, of course these will only be generating power during the day and even then the amount generated will be depend on cloud coverage etc. So we needed some other ideas.
One element that is always present day and night is wind (well more so than the sun!), So we set out to harness this and came up with the following idea;
In-pipe Water Turbine
When we were in the early stages of designing the Autonboat I wanted to put a small turbine on the keel, the turbine would of turned when Auton sailed forward and generated a small amount of power. This would of only been a small amount of generation but it would of been more or less constant (It really is windy at sea!) and would of aided the Solar Cells nicely. There was one big problem in my thinking, a prop on the keel is a prime candidate for dragging rubbish around the sea (think old fishing nets, seaweed etc.) so I was forced to abandoned the idea.
Couple of days ago I came up with a similar idea, instead of having the prop out in the open just waiting to catch an old fishing net, I thought about channelling the water inside the hull. There would be an opening at the front of the hull with a straight pipe exiting at the back of the hull to allow least resistance for the water to flow through. The openings would be covered with a mesh that would only allow water through. Below is a quick mock up of the idea;
An alternative to the above would be to have both the motor and prop inside the pipe (sort of how a jet engine is), at the moment it looks like I’d need to use a pipe with a fairly big diameter. Space is at a premium inside Auton and I’d rather not increase the flow of water inside the hull. If I can find a motor small enough I’ll test this idea. I’ve been looking at a maximum diameter of between 40 and 60mm.
Again I have a lot of testing to do on this front and of course it’s not going to generate lots of power, but it could be useful for trickle charging the batteries as long as Auton is moving forward. I would probably go for one of these on each side of Auton to better aid the weight distribution. Of course I need to look into what effects this might have on the sailing ability of Auton and if the efficiency of more than one generator on each pipe would be worthwhile. I also need to look into where to place the wholes at the front to catch water, right at the front might not catch enough water so the opening could be half way down the hull like in the below picture (pipe highlighted in red).
As I said above, I still have a lot to test out with this idea and it’s not 100% if they’ll make the boat. If you have any input or ideas then please feel free to drop by our forums.