Sunday, May 31, 2009

[Electric Boats] Re: Recommendations for a 48volt to 12 volt dc to dc converter?



Lamar,

Sevcon 48v to 12v DC/DC converter gives 13v, 25amps, $200. Stack two in parallel and get 50amps.

http://www.electricmotorsport.com/store/ems_ev_parts_dc_dc_converters_sevcon.php

Mark Stafford... no financial interest or personal experience with Sevcon.

--- In electricboats@yahoogroups.com, "lmfelder" <lamarfelder@...> wrote:
>
> I have a columbia 36 that I have converted to electric and I want to add a 48 to 12 volt dc to dc converter -- does anyone have any recommendations as to brand or where to get etc? I had been using one bank to power my motor and one bank for house but I would rather increase my range and just pull house of of the 48 volt bank.
>
> Thanks
>

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Re: [Electric Boats] Recommendations for a 48volt to 12 volt dc to dc converter?



Wonder if anyone has used converters from this company Powerstream? http://www.powerstream.com/ they seem to have a variety, although not very high amperage. More suitable to trickle charge.

Sailonner

> > I have a columbia 36 that I have converted to electric and I want to
> > add a 48 to 12 volt dc to dc converter -- does anyone have any
> > recommendations as to brand or where to get etc? I had been using
> > one bank to power my motor and one bank for house but I would rather
> > increase my range and just pull house of of the 48 volt bank.
> >
> > Thanks
> >
> >
>
> [Non-text portions of this message have been removed]
>
>
>
>
>
> [Non-text portions of this message have been removed]
>

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Re: [Electric Boats] RE: Electric power for over 30'




Hey Tom......no offense taken here, if you can't rip on your friends then you should get better friends....  
Chuckle....
 
Dave K    "put a charge in your life, GO ELECTRIC"
 
 
OK, my real name IS Tom.
I just don't take myself very seriously and hope I haven't  offended anyone
as a result.

[Non-text portions of this message have been removed]

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[Electric Boats] 2.9 knots @ 17 Amps



Just a note as we are beginning to do some serious sea trials on our new Electric Yacht drive.

We just hauled the boat and painted so we have a clean bottom but running with just a kiss of throttle and about seven knots of wind we were able to sustain 2.9 knots with 17 Amps.

We are even more impressed with how accurate the Electric Yacht monitoring system is...

More soon come as we continues the testing.

Bob

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

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Re: [Electric Boats] RE: Electric power for over 30' [Question for Dave K]



Keith, If I can keep my family healthy and in an un-needy condition I'll get back to that job.  Right now I'm back up in Michigan helping my sister with our mom, life has a habit of getting in the way some times...   Dave k

--- On Sat, 5/30/09, aweekdaysailor <aweekdaysailor@yahoo.com> wrote:

From: aweekdaysailor <aweekdaysailor@yahoo.com>
Subject: Re: [Electric Boats] RE: Electric power for over 30' [Question for Dave K]
To: electricboats@yahoogroups.com
Date: Saturday, May 30, 2009, 8:53 PM

Dave is also using a Rice nozzle which if memory serves works at higher speeds than a Kort.

Dave - Regen numbers!! Get those sails up! I'm excited to see some forward progress (esp since I've blown Yet Another Controller and am down again...damn keyswitches...)

-Keith

[Non-text portions of this message have been removed]

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Saturday, May 30, 2009

Re: [Electric Boats] Re: Electric power for over 30'



Thanks Keith:
My plans are to do some extended blue water cruising with my first
officer. (20 year old daughter)

The dual motor/dual controller I feel at this point is a safety issue.
So yeah.
I was looking at 2 of the 8 HP DC motors but will re-consider.

My 'Diesel Credit' in weight i have been told with V-drive is around
900 pounds. There's lots of 'stuff' hanging on that boat anchor. (Big boat)
With the removal of the Diesel Tank, there may be more room than i need
and may need to add ballast in addition to batteries.
-Tom-


In a message dated 5/30/2009 9:10:47 P.M. Eastern Daylight Time,
aweekdaysailor@yahoo.com writes:

What are your expected sailing conditions (winds, tides, chop, etc). It has
a lot to do with how you size the system.

Based on my experience (Hunter 30 9800lb disp) I would go with one of
those dual-motor/dual-Based on my experience (Hunter 30 9800lb disp) I would
go with one of those dual-motor/dual-<WBR>cont

Someone just posted on one for sale but I think the numbers (9KW @ 24V)
were wonky - that's probably the 48 or 72V max HP rating.

9KW is about 12HP - should handle most conditions just fine on your boat
as long as the batteries hold out. That's the real problem on larger boats -
your "diesel credit" in weight isn't much better than mine, but you need
more power, so you're either going to be heavy or have less range.

-Keith

--- In _electricboats@electricboatele_
(mailto:electricboats@yahoogroups.com) , "Tom" <iloveamercedes@ilo> wrote:
>
> Hello everyone!
> I know there must be a thread for powering sailboats over 30' with
electric motors. Can someone direct me to it?
> My sailboat is a Cal 35 Cruising. She is of 15,000 lbs. Displacement.
> I think this project would need around 35 hp. She has a 4-108 Perkins of
'Claimed' 50HP hahahaha!
> Anyway, with what little I know about this, I would need a bank of about
5 Golf Cart Batteries.
> I also want to utilize Solar Panels as well as a Gas Power Generator.
> So let me know how screwed up my ideas are so I can get an idea of where
to start here.
> Thanks
>

**************A Good Credit Score is 700 or Above. See yours in just 2 easy
steps!
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[Non-text portions of this message have been removed]

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Posted by at No comments:

[Electric Boats] Re: Electric power for over 30'



What are your expected sailing conditions (winds, tides, chop, etc). It has a lot to do with how you size the system.

Based on my experience (Hunter 30 9800lb disp) I would go with one of those dual-motor/dual-controller setups - so you have max HP when needed, as well as backup emergency go if you lose 1 system.

Someone just posted on one for sale but I think the numbers (9KW @ 24V) were wonky - that's probably the 48 or 72V max HP rating.

9KW is about 12HP - should handle most conditions just fine on your boat as long as the batteries hold out. That's the real problem on larger boats - your "diesel credit" in weight isn't much better than mine, but you need more power, so you're either going to be heavy or have less range.

-Keith

--- In electricboats@yahoogroups.com, "Tom" <iloveamercedes@...> wrote:
>
> Hello everyone!
> I know there must be a thread for powering sailboats over 30' with electric motors. Can someone direct me to it?
> My sailboat is a Cal 35 Cruising. She is of 15,000 lbs. Displacement.
> I think this project would need around 35 hp. She has a 4-108 Perkins of 'Claimed' 50HP hahahaha!
> Anyway, with what little I know about this, I would need a bank of about 5 Golf Cart Batteries.
> I also want to utilize Solar Panels as well as a Gas Power Generator.
> So let me know how screwed up my ideas are so I can get an idea of where to start here.
> Thanks
>

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Re: [Electric Boats] RE: Electric power for over 30' [Question for Dave K]



Dave is also using a Rice nozzle which if memory serves works at higher speeds than a Kort.

Dave - Regen numbers!! Get those sails up! I'm excited to see some forward progress (esp since I've blown Yet Another Controller and am down again...damn keyswitches...)

-Keith

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[Electric Boats] Re: Recommendations for a 48volt to 12 volt dc to dc converter?



After several failed experiments (my loss your gain) I am using 2 of Thunderstruck's inexpensive 10amp controllers in parallel. I see no RF interference issues (you have to have faith and connect your 12V and 48V negatives - I was expecting ghostbuster-like fireworks...).

Ideally - figure out your max amp draw then build for 150% of that - so on my boat 20amps is about max (water pressure, lights, sumps) - I should ideally have 3 ganged together for N+1 redundency. They are so cheap (~$25) as to be nearly disposable so carry a spare. The other cool thing to think about is running a +48V "backbone" and converting locally where the power is needed. I built up a breadboard with a +48 bar, and a dual-bus +-12V and then connected the -12V and -48V.

The downside to these units is they can't charge a 12V battery as they put out exactly 12V.

I have lost a couple in playing around - one where I probably reversed the polarity the other where I am somewhat suspicious that back-emf from a fan got to it. In both cases they got real hot and a cap popped.

Anyway, been running with these for a couple of months now and no troubles.

-Keith

--- In electricboats@yahoogroups.com, "lmfelder" <lamarfelder@...> wrote:
>
> I have a columbia 36 that I have converted to electric and I want to add a 48 to 12 volt dc to dc converter -- does anyone have any recommendations as to brand or where to get etc? I had been using one bank to power my motor and one bank for house but I would rather increase my range and just pull house of of the 48 volt bank.
>
> Thanks
>

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Re: [Electric Boats] RE: Electric power for over 30' [Question for Dave K]





This is all interesting but not very relevant unless you are building an electric tugboat.  It's like comparing the ability to pull a plow with a 40 hp John Deere tractor vs a 400 hp Corvette.  I bet the tractor wins.
 
DK 
"I believe you are correct Dennis and since I have given up on the Corvette idea I'll continue with my Johnny Dearest, the speed is much closer to the JD anyway"
 
A prop in a nozzle has much greater efficiency at zero speed (who cares how efficient it is at zero?) but the efficiency drops off fast as the boat gets moving through the water. 
 
DK 
"not going to debate you on this one Dennis but I don't think you are quite correct.  The Nozzle is good up to about 14/15 knots, the effecieny does go down but still better than an open prop
 
 
 Dennis, I wasn't trying to compare HP between the 2, just make a comparrison with increased effeciency you can improve your proformance and add to your battery bank life...       So no argument on my end

Always enjoy your posts, lots of insight and experience from the real world...  I will crawl back in my effeciency box and regen hole and be quiet....
 
Dave K

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