Question about electric propulsion

I am totally new to all this, so I hope you will bear with me on this question. The extent of my knowledge about elctricity is that I know if I plug in appliance in most of the time it will work. I am just starting to research the whole subject of electric boats.

My question is: If you are using an electric motor to power your boat, rather than using a diesel/gas generator, could the electric generating portion be attached somehow to the shaft so that power is generated for recharging batteries while turning? In effect continually recharging your batteries and providing power to the motor. The batteries would be used to get the process started and for house power. Add maybe solar panels for charging while at a stop or moored.

I know there has to be a very good reason why this is impossible.

 

Hi Scibbema,

You're not the first. Do a search, there is a thread active on one of the forums. To answer your question - which is a one asked by every one who is not technically involved because it looks so logical - the losses and efficiency of various components cause you to lose so much energy that it cannot be self sustained.

In such a closed loop of motor to alternator to motor to... you will have to have a more than 100% efficiency on at least one of the components which has not been achieved yet. 100% or less efficiency means energy is lost along the path that cannot be regained again in a usable form.

You have to turn a prop in the water under your own man power to propell a boat to realize how much power is required to do so. Motor's have horse power and not man power for a reason. You will fit a LOT of guys in there to make one horse power.

And you have to turn an alternator under your own man power to generate enough power to work a low power app like a 12 V Tv ro realize how much energy all this requires. The biggest drilling machine you can buy will not turn that alternator, not even close.

To do anything sensable like this requires smart planning and smart (expensive) equipment and loooots of power and beeeeg batteries and you still have energy problems with the fuel motor/generator/solar/wind gen.

If it was possible, none of us would bother to buy the fuel model.

 

If it is a sailing boat , yes it is possible to generate power from a trailing propshaft, but otherwise, as Fanie says.

 

Hi Scibbema, You will find lots of challenges ahead, but in the end a boat is a compromise and something into which one pours money in order to keep things in operation and afloat...

For starters, have a look through my build project (only 31 pages so far and the build time is expected to be 12 months (started 23 April 2009)... I am using a pair of torqeedo 4.R electric outboards, supported by about 80 sq metres of sail, a 21 hp diesel battery charger (48V battery system) and 2000 watts of solar panels as a live-aboard cruiser... - That is my choice for the cruising grounds I will play in... Your choice may be different, but it may give you some ideas... Good luck...

 

My neighbor had solar panels, batteries and an AC inverter for house power. Then he also installed a battery charger that converts AC back to 12v. Instead of providing extra charge, the batteries were depleted faster than before.
I tried to explain it to him the way Fanie did, but he is an opera singer.....

Over the centuries, may have tried in vain to invent the "perpetuum mobile".

 

There is one at the Queensland University "science museum" in the quadrangle. - just a weird pendulum device that seems to run perpetually - I think it has swung, oscillated and rotated for a year or so to my understanding - a rather useless toy, but a good talking point for the observant... Just down the hall a bit from the display of a bit of pitch being poured through a funnel - several drops have taken some 30 or more years to fall so far - far slower than watching paint dry.... - - sorry got a bit carried away there with some trivia...

 

Looots and loooots of alternative energy sources have been developed in the past. Some of these include 'free energy', but it was always 'bought out' by the fuel companies and then there were those who disappeared.

They want you to believe there is no such thing as 'free energy', if you don't believe it exist, well, don't make a fool of yourself just yet

This catagorise under these -

The earth is flat and you can fall off the end of it (we were a bit gullable then)
Man cannot fly (Two wrongs don't make a right, but two wrights made an aeroplane)
Other's... space travel, Tv, home computer, internet etc etc that is now commonly excepted. It was not not so long ago...

Free energy (soon... really soon, the world is ready for it)

 

I kind of figured it would be something like that... As stated: It just seems too logical to actually work. I was hoping at most it would allow batteries to deplete more slowly increasing the range... Thanks for the info, all.

 

There are still energy sources that we as humans have not accessed yet, look for stuff called "dark matter" as it makes up a significant part of the universe - called such because no one has seen it yet and cannot contain it to determine its composition, then there is lots of other stuff that holds huge amounts of energy but passes through everything we presently know.... Ponder that and put names to that which has not been named by me

 

Over unity machines are prohibited by the first law of thermodynamics. You can't even come close to breaking even on these schemes because of frictional and other losses. There is no such thing as a free ride or free energy that costs nothing. To capture the "free" wind or "free" solar energy costs thousands of dollars for the initial machine and untold amounts of time, money and human attention to keep them running.

One silly scheme proposed that cars don't need any energy to run at all. They can be powered forever by gravity by putting smaller wheels in front and larger in the rear- that way they are always by the slant running downhill powered by gravity! All the silly schemes with 1000 miles per gallon fuel injectors, compressed air cars, water powered cars, alternator on the wheel, etc. are hoaxes. When there are working models, they sometimes fool scientists and engineers for awhile, because these people are not trained to think like magicians. It takes a trained magician to find the hidden compartments, mirrors etc. which are being used in deception. I believe the magician "Rhandi" has exposed many of these and has a large standing monetary award for what he can't disprove.


Please do not take my comments in the wrong way, they are not directed at anyone, but are just trying to help.

Porta

 

Oops, here's the guy offering reward for free energy:
http://www.phact.org/e/realfree.htm

Randi hasn't been around for awhile and was more interested in psychokinesis type stuff....

Porta

 

http://images.google.fi/imgres?imgu...nt=firefox-a&rls=org.mozilla:fi:official&sa=G

Has anybody seen a possibility of wave energy powering cargoships and large vessels?