Electric Sail Boat
I have a 10 - 12 Ton Monohull yacht. I would like to install an electric motor, as main power.
I have been recommended a 3.7Hp 36V motor as aprox suitable, I'm not an electrician (I AM a sailor!!) and the controller and bits & pieces of this motor presented a mine field for me!
The best solution I have so far come up with is the mentioned 3.7Hp brush motor out of a golf cart, however I would like to have a regenerating motor to assist in re-charging whilst I am under sail. I would also like to install a solar array for charging whist NOT under sail!
If somebody has been down this road already, or anyone else can offer any useful advice, I would appreciate this greatly. Even if you are not a sailor, or have any experience with boats - I just need a bit of guidance as to what technology is available and how to apply it. To date, my efforts normally have resulted in "we dont have anything to suit a boat" before they even hear me out!!
CGB Electric Sailor
Where are you? I am not a sailor, but I understand electronics, physics, and mechanics, and am willing to discuss this project with you. I am in Maryland, USA. Hopefully we can make voice contact, perhaps by telephone? Let me know, if this seems feasable.--Bob
Electric Motorsport (http://electricmotorsport.com) has been helping people electrify their boats for a long time. They have some kits on their website for this purpose.
I have my doubts about whether it will work to use regen while "under sail" to recharge the battery pack. I'd be confident that while at anchor that regen would charge the pack. But under sail?
I don't spend much (hardly any) time in marina's except a few years back when I spent a lot of time with a friend who lives(d) aboard her sailboat. I'm sure you're already aware of this - but there are several kinds of solar panel and wind turbine kits meant for sailboat use. e.g. I see them in West Marine's catalog.
ok thanks bob , i am in north east australia. my past experience is that i lived on a 46 ft ketch with my family for 20 years. i had a dog clutch to allow the propellor to spin while sailing this gave about 5 amps via a lay shaft and alternator. the normal rule is to allow about 20% slip when calculating efficency, but 80% in reverse which it is while sailing. also try to have no more than 700rpm for efficency. which means that a 80hp motor at 2100rpm should be through a 3:1 gearbox. saildrive then becomes 20% of 700rpm. my present problem is that i had a 36hp motor (seized)through a 2:1 box. i am happy to keep the same prop, but i realise i may have to reduce drive it with v belts.apparently i have been told that 3.5 hp in electric is about 35hp for a diesel motor. is this correct? so i am looking for this size motor. i am quite happy with solar panels for charging and have been using them constantly for cooking and light via an inverter since 1986.i figure that most of my time out of port is spent sailing and i would not use an engine for more than 4 hours to enter or leave port and i was calculating on having battery reserve for 8 hours. depending on the size of the motor this should be about 150 to 180 amp hour. also i have been advised to run the 36 volt motor on 48 volts to get better efficency and less amp draw. does this all seem like a plausible place to start? i realise that regeneration will probably only give 3amps on this system but this is sufficent for navigation lights at night and still gives approx 70 amps in a 24 hour period.
thanks reikiman for the tip on electricmotorsport. very helpful- might turn out to be exactly what i"m looking for but you have me stumped on your comment about regen not working under sail but possibly at anchor, why do you say that?am i missing some important information?
you have me stumped on your comment about regen not working under sail but possibly at anchor, why do you say that?am i missing some important information?
Well, I don't really know and it's clear you have a lot more experience than I do. My hunch guess was that - while sailing - a prop down in the water wouldn't turn strongly enough to cause enough regen to be worthwhile. But you made a followup about doing exactly this with prior equipment. Maybe my assumption was wrong.
While I'm no expert, I'l put in my 2 cents worth. Having designed and built a 14' solar/battery electric boat nearly 15 years ago, I'm still tweeking it. Lithium batts are
now on my shopping list. Here are my thoughts.
First, get the book called "ELECTRIC BOATS" by Douglas Little. He deals primarily with small boats, but the basic principles are universal.
Seacond, I would recomend a brushed motor. When you blow the controller, it's still possible hot wire the batts directly to motor. Not ideal, but in my case it sure beat rowing to shore dragging a 10" prop. For your size boat a Lynch motor might work.
Third, a controller from 4QD.(www.4QD.co.uk). I bought mine from Silent Technologies
Inc. (828-694-1161), hopefully they're still in business. The reason I chose this controller is twofold. It has a wide voltage range which is usefull for connecting to solar direct without frying the controller. It also is a 4 quadrant controller: forward,reverse,speed and regen. This eliminates F/R contactor. One less thing to fail,
and no voltage conversions to operate relay. In my case, one less reason to row back to shore dragging a 10" prop! I have never used regen capability, but with a sailboat the controller doesn't care what kind of "wheel" is generating.
I hope this helps you in your search.