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Go Back   SailNet Community > On Board > Gear & Maintenance > Looking for Feedback on Electric Propulsion
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Thread: Looking for Feedback on Electric Propulsion Reply to Thread
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Topic Review (Newest First)
05-06-2008 01:00 PM
chucklesR SeanSeanmour,

great links, good info - unfortunately none of it changed my mind so far.

For me it still comes down to batteries and time.

It's not time for batteries yet.

"The completed battery pack contained 18 six-pack building blocks with 108 individual batteries. The total weight was 930 pounds. Total volume was around eight cubic feet. Because of their greater discharge capacity, Tether's 162 amp-hour configuration is equal in performance to 12 AGM 4D batteries in series, but is 30% lighter.

The 162 amp-hours of Tether's test configuration proved to be more than enough capacity for the Lagoon 47 testbed. It has two 9 kw motors that draw 64 amps each at maximum throttle. The same capacity should work fine on the hybrid Lagoon 500s, Tether says. "It's a heavier boat with 16 kw motors, but the waterline is longer so it's more easily driven."

"
They don't give a price - they hope is becomes comparable (over time) with the 16 life line 8d's agm's it's replacing (about 9.5k). These are about the best batteries out there you can buy at this point in time.

Future batteries don't push my boat.

That's less than 3 hours motor time on the batteries. Great if the gale force winds blowing me to the lee shore abate in time, not so good if not. The two 20kw gensets (29 hp?) on that boat are each about what I have as a full up motor - and replace the 50HP diesels that the old ugly non-green Lagoon's have. Doesn't seem to make sense to me to have two gensets, electric motors, controllers and a ton of batteries so I can get what? Have smaller diesels? That's the whole deal?

No thanks.

I'll go green by sailing more.
05-06-2008 12:07 PM
seanseamour
GreebBoatBateauVert database

Having just found your thread I suggest you have a look at the webiste we are building - so much is happening so quickly that it is difficult to decide what is the best way to go. If you are thinking of going diesel-electric there are many configurations, we know a few up and running, have several developments under waygreenboatbateauvert.com. Happy to share any knowledge we have, much more than published.
05-01-2008 06:44 PM
buckeyesailor You can have one of my cookies Wombat!
05-01-2008 06:10 PM
engele
Torque Curve

Quote:
Originally Posted by Goodnewsboy View Post
26 Horsepower magically becomes 40 horsepower? Physics doesn't work that way. Something is still rotten in Denmark.
I think the rational for using a lower HP electric to replace a gas or diesel is that the torque curve is flat. You don't need to rev your engine up to get your torque, thus you can get away with less. I am not sure if that is what you were getting at or not, but that is my understanding of the reasoning.

Looking at the electric car sites, that seams to be the reasoning they are selling as well,
05-01-2008 06:05 PM
engele
As well as

Quote:
Originally Posted by Goodnewsboy View Post
You seem to want to make your boat an electric hybrid. Here are a few facts:

1. The area near the shaft log in a boat is not a real friendly atmosphere for continuously running electric motors, especially those that have commutators.

2. A hybrid system is usually less efficient. Think of it as the sum of INefficiencies. You have the inefficiency of the engine, the inefficiency of the generator, the inefficiency of the batteries, the inefficiency of the motor controls (analogous to the throttle), and finally, the inefficiency of the motor. If it were a car, you would make a significant gain in fuel efficiency whenever driving in the city because you would consume no energy when stopped. (That is the big advantage of hybrid autos over those gas burning engines at idle.)

Your conventional marine engine has inefficiencies too, but fewer; engine, transmission. (I am assuming that parasitic loads such as the alternator and pumps are figured into the engine performance.)

3. Electric advantages:
Silence

But there are a few factors not considered here:

1: We have motors (alternators, blowers, etc), in our current engine bays already.

2: Because of the flat torque curve, we need less of an engine than our current engines in a hybrid setup (the genset doesn't need to have a lot of power, just maintain enough to create enough charge capacity). Also you can peak your electric more than your charging capacity because of your batteries, without the torque curve you would have to gun your engine to get up to the needed rpms to get power.

Just so you know, I haven't installed one of these systems either, but I am interested.

Both of those factors may not weigh out enough to make an electric system worthwhile, but at least they do represent some positives that are often overlooked.

I am interested in these systems as well.
04-12-2007 10:16 PM
sailingdog Bad Wombat... no cookie for you.
04-12-2007 09:09 PM
tdw I've been reading about something called a solar st......nah, that's just too cruel.
04-12-2007 08:37 PM
sailingdog Also, relying on a system that is dependent on electricity to the degree an e-power system is on a small sailboat is somewhat unwise. Large ships can do this, because they have the space and capacity to have redundant systems, but small sailboats do not.
04-12-2007 08:15 PM
JouvertSpirit I thought about this option for a long time and finally just had a 3 cylinder Yanmar installed. I just posted a picture of it at the end of the Re-E-Power thread. There was just not enough duration and power on the pure electric units. The genset option just adds to the whole thing of something else to maintain, and at that point I just decided to get a standard diesel installation.

The 20HP Yanmar will provide all I need and is incredibly fuel efficient and remarkably quiet considering I was used to hearing a 30 year old Farymann.
04-12-2007 06:17 PM
sailingdog
Quote:
Originally Posted by sailawayjnl
The benefits of dealing with the Father of Electric propulsion is something that can really wake up an industry of change. Dave Tether started all the marine propulsion many years ago and has now formed a users group for formal and informal information.

make sure you visit if your interested.
Sailawayjnl-

Any reason you're spamming the forums with the same message. This is the fourth one I've seen from you with basically the exact same content.
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