Eric's electric propulsion & other electric motor discussion

[Lynx]

True, a lot of the inboard engin boats have to lock the prop to save the transmission. If not aligned with the keel would create more drag. Yuk.

[Captain Smollett]

True, a lot of the inboard engin boats have to lock the prop to save the transmission. If not aligned with the keel would create more drag. Yuk.

Right, but what Hiscock was saying was that this is additional drag over and above what is already there from the prop with the shaft locked.  Maybe we could call it something like "asynchronous rotational drag" or something fancy sounding.   

I kinda see it in my mind's eye as a kind of 'reverse cavitation.'  In cavitation, the prop is turning too fast; in this case, it is turning too slow.

No doubt light air is tricky anyway.  I recall that the Pardey's wrote quite a bit about "Keeping Her Moving in Light Air" as an important component of sailing far on the cheap.  Drag played heavy into their discussion and key there was feathering props.

Heavy air gets all the press, but I think light air makes the sailor.  At least light air gives ME the opportunity to show how much I have yet to learn....

[newt]

Back to a feathering prop in light air-
I see a couple of situations.
No prop rotation in light air- no generation- your are just trying to get the boat from one place to another. If you have full batteries- you may electric motor for a while. Otherwise you fold the prop to the least resistance.
Air starts to fill in: If you really need juice, you waste it on the generator, otherwise you sail.
Above 7-10 knots of wind- do both with the caveat that you have more drag, so you may wish to keep a little more sail out. Once you have your 800 amp hours charged up, you should be able to enjoy a movie and a motor into a harbor for free
(all of this is theory and has not, as yet been tested in anything larger than a bicycle)
feeling sparky!

[olivertwist]

There was a problem with my initial installation. She took a little water when first launched. I've already  reglassed the hull/motor interface and will be down at the boat tomorrow attempting to over build it before attempting to relaunch and test.
All indications are that the re-e-power motor is working fine but my installation was lacking. With luck, and the grace of God, I'll get back to you on Monday with better news.

Oliver

[olivertwist]

The 'grace of gosh', is the result of someones filter. To me it doesn't sound quite right.

[Lynx]

To me it doesn't sound quite right.

To each his own "gosh".

[olivertwist]

I've been using the re-e-power system 3000 regularly now and I'm gaining confidence in it. It runs reliably and is much quieter than the diesel.  However, it's noisier that the diesel when you turn it off and sail without power. It hums while you sail.  It's not a big deal but it surprised me.

I run the engine for about 25 minutes on the way down the river to LI Sound and about the same coming in. I've been running it at about 10 Amps which gives me 3 to 3.5 knots.  Wide open it draws 90 Amps. I haven't run it long wide open so I don't know how fast it would push me. At 10 Amps I should get 14 hours with the 4 Series 31 batteries.

I keep Credo at a slip with electric so I charge up at the dock. The charger delivers 9 Amps and the time spent charging is about equal to the time spent discharging.

I don't have much to report on recharging while sailing yet. The winds have been light  most of the time so I haven't tried this much. yet. I did note that engaging the re-gen costs about half a know just as advertised.  I was also concerned about the induced drag of the pod but the boat still gets to hull speed in moderate winds so it doesn't seem to be an issue.

So far I like the ease of operation, the quietness, the lack of fuel and smoke, and the ease of maintenance.

[s/v Faith]

Thanks for the update, here is a grog to celibrate!

  Bet you are glad it is workingout well, thanks for being the guinea pig for the rest of us.  I look forward to hearing more about it as you get more experience with it. 

 

[newt]

Any more news Oliver? That hum may be the generator noise, which if working, would make me feel good.
Captain, as I look through this thread I realize I may not have answered your question- how would I generate electricity in light air? Either  1. no generation because I have a big enough battery bank or 2. Solar.

[olivertwist]

Newt, nothing new yet.

The wind forecast looks good this weekend so I should get to try charging under sail. I plan to reverse the wires on the ammeter to see what kind of charging current I get.

[Lynx]

Is this a 48 volt motor?

10 amps X 48 volts = 480 watts (less than 1 hoursepower). If you put up 1000 watts of solar panels you could handle it without anything else.
How big is 1000 watts of sloar panels?

An option.

[AdriftAtSea]

A 130 watt solar panel is about 26" x 60" or so... you'd need eight of them to get 1000W.  That would require  a space 5' x 22' or 10' x 11' or so.  Not really feasible on a boat that is less than 40' LOA, and tough to do on a boat that size even.

[olivertwist]

The updated wind forecast for CT doesn't look good for testing the ability to recharge under sail. I'll be bringing my 1.8 kW gas generator with me. I may motor across LI Sound and back (or until the batteries die) and then use the generator to drive the 48V recharger to get back. The charger draws 9A. 48V * 9A = 432W. The charger has more than enough power.

[newt]

If I may tease you a bit-
The above logic on solar panels implies that you are running your electric motor directly from the solar array, and yes it would have to be big- impractical on a sailboat. If however you already had a large bank of energy saved (say 1000+ amp hours at 12 v (12000 watts), you could motor through the doldrums or other windless area, or not use your water generator for light wind sailing, then repelish with a smaller solar panel and a water generator as the wind picks up.  This large battery bank would be with the rest of the lead- close to the keel. In fact, if I got serious with this, I would look at taking a part of the keel out and replacing with secured lead batteries.
Since we don't spend the majority of time cruising (most of it is spent at anchor or in ports) the sun would keep our banks up and enough electricity in reserve.
BTW- 1000 amp hours could be as little as 10 batteries- or about 600 lbs- and that would be for a larger boat. I would think that boats under 30 feet could probably cruise for a lot less. Remember you would be replacing your engine and transmission with this arrangement, so you would get heavier, but perhaps by not very much.

[s/v Faith]

Just saw this on the Pearson Ariel board, where it was posted by the user 'Commander Willbe'  He is looking for a Pearson Commander (same hull as the Ariel, longer cockpit and a shorter cabin) Anyone know of any for sale?.

   It looks like another promising option.

  ASMO Marine Thoosa 6000 48v system (PDF Warning)

The Thoosa 6000 is a 48 V system.
The system uses a permanent magnet motor, set up in a
gearing console made in stainless steel and is regulated
by a 4-quadrant motor controller.
Thoosa 6000THOOSA 6000
Electric Inboard Drive Systems
6kW continuously power
(Replaces a 12~18HP combustion engine)

[s/v Faith]

Quoted from the battery thread;

Wanted to add, that while doing research on electric drives (i've decided im going that route) I came across this little gem for you guys that are using flooded lead acid.

http://www.flow-rite.com/battery-watering/millennium-spw

Nowell, I love the idea of electric drive.  I hope you will share the details of your setup and any other details you may come across. 

Intresting blog about a cruiser that uses an Electric Yacht kit (on my short list). At times a little preachy, but overall, great insight!

http://boatbits.blogspot.com/

Anyway, back on topic of batteries

[evantica]

Hi. Do "you" have anything like this in the US or else? how's the price if?

[LooseMoose]

Electric Yacht (http://www.electricyacht.com )makes a great electric propulsion system. Certainly affordable than going with an internal combustion system. we've had out for a couple years now on our CAL 34 and it's awesome!


Bob
http://boatbits.blogspot.com/
http://fishingundersail.blogspot.com/
http://islandgourmand.blogspot.com/

[s/v Faith]

Hi. Do "you" have anything like this in the US or else? how's the price if?

I went ahead and merged this into the thread on electric propulsion.  THere is a bunch of good info here.

You also might want to read up on the Pearson Commander #227 here on the Ariel forum.  Through discussion of different options and break down of all costs related to the conversion.... pretty boat too.

[evantica]

Wahoo great. This must be the right way to "engine" your boat! Thanks for info! are there any other retailers/ producers maybe?