Sunday, December 6, 2009

RE: [Electric Boats] Re: Electric Catamaran

 


From: Eric

PV panels don't generate any heat, but they do collect it. Hard panels over
a hard bimini actually lower the temperature on deck, underneath the cover.
The panels need a small air gap for cooling so the hard bimini ends up in
the shade. Many people use the panels as their bimini with nothing
underneath, these act similar to a regular hard top, though probably a
little warmer underneath because they're black on top. Putting an additional
layer between you and the panels, perhaps even canvas, should mitigate that
issue.

You can probably guess, I'm trying to save a couple pounds wherever I can. I
was thinking of going with a targa style arch in the back for my traveler
and attaching the panels to that with aluminum supports and tying it
altogether with a walkway down the center (basically an aluminum frame
holding up everything). I can't have exposed wiring under the bimini so I'll
probably have to go with the continuous hard bimini, front to back.

I've just spent the last couple hours shopping for electric motors. I'm
wondering if I can get away with something in the 36 volt range. These guys
(www.kraeutler.at) have a couple that look interesting. They make a variety
of power systems, including sail drives. I know the Volvo diesel sail drives
have been a nightmare on the bigger charter cats. I don't think these are
regenerative either, unlike the Asmo.

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[Electric Boats] Re: Electric Catamaran

 

Bill,

PV panels don't generate any heat, but they do collect it. Hard panels over a hard bimini actually lower the temperature on deck, underneath the cover. The panels need a small air gap for cooling so the hard bimini ends up in the shade. Many people use the panels as their bimini with nothing underneath, these act similar to a regular hard top, though probably a little warmer underneath because they're black on top. Putting an additional layer between you and the panels, perhaps even canvas, should mitigate that issue.

Eric

--- In electricboats@yahoogroups.com, "Bill Gow" <billgow@...> wrote:
>
>
> From: Eric
>
>
>
> It looks like 8 panels could get squeezed onto the same space, which could
> deliver 2.5Kw under optimum conditions.
> [Bill Gow] I can't do that, I need a couple feet at the back of the bimini
> for my traveler. If anything, I'd like to cut the bimini back a foot or two
> but it works at this size. The extra room to work up there is a nice feature
> as well as the tremendous power advantage!
>
> How much heat will these things generate up there? Am I going to roast under
> these things...?? ;)
>

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RE: [Electric Boats] Re: Electric Catamaran

 


From: Eric

It looks like 8 panels could get squeezed onto the same space, which could
deliver 2.5Kw under optimum conditions.
[Bill Gow] I can't do that, I need a couple feet at the back of the bimini
for my traveler. If anything, I'd like to cut the bimini back a foot or two
but it works at this size. The extra room to work up there is a nice feature
as well as the tremendous power advantage!

How much heat will these things generate up there? Am I going to roast under
these things...?? ;)

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RE: [Electric Boats] Re: Electric Catamaran

 

From: luv2bsailin

I believe these are the most efficient PV panels on the market.

http://us.sunpowercorp.com/residential/products-services/products/panels.php

[Bill Gow]  Wow! Those are really a leap ahead of everything I've been looking at so far. They would add ~200 Lbs to my bimini and ~3.5 times the power of the Uni-Solar laminates. They're also not much bigger than most of the 200 to 220 W panels I've looked at. I'd get about another 1.5' of walkway between panels to tend to  sails, etc. up there too. Nice suggestion!
 
I sent e/m's to a couple outfits that make Lithium Iron Phosphate batteries to get an idea of what I'd need. Currently, I'm looking at the Asmo THOOSA 6000 motors (48V, 140A, 6.1KW). I'm probably a long ways away from what I need, though. Diesel electric may still be an option but after I add up the weight, I think I'll still have to back into the outboards. Whatever I end up with, these panels are worth considering.

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[Electric Boats] Re: Electric Catamaran

 

Jim,

It's nice to see that PV manufacturers are getting close to 20% efficiency. Looking at the original request for panels that would fit on a 13' x 14' hard top, using 6 of these panels would generate over 1800w and have some room left over for walking access between the panels. It looks like 8 panels could get squeezed onto the same space, which could deliver 2.5Kw under optimum conditions.

Using the standard capacity conversion of six times the rating wattage to figure the daily output, the six panel setup could generate 11Kwh/day and the 8 panel array could generate an impressive 15Kwh daily. The trade off here is the hard panels are less tolerant of impact and abuse. Of course, during foul weather situations, the panels would deliver little power, right when you would want(need) it most...

Still, these kind of figures show the progress made in PV electricity collection and for boats with sufficient area that is appropriate for a solar array, a boat could operate as energy independent for a considerable time.

Fair winds,
Eric
Marina del Rey

--- In electricboats@yahoogroups.com, "luv2bsailin" <luv2bsailin@...> wrote:
>
> I believe these are the most efficient PV panels on the market.
>
> http://us.sunpowercorp.com/residential/products-services/products/panels.php
>
> I've been looking at the 315s for my modified Duffy launch. They are 41x63 inches and put out 315W at peak.
>
> Jim
>
> (If anyone is curious, I've got an old Duffy 18 double-ender with an Electric Yacht system and an oversized prop. According to the numbers, 3 of those panels will allow me to do over 4kt on pure solar. There's also room for 12 Trojan T-125s in the battery hold, which would give me a range of around 50 miles at 4.5 to 5 kt. I haven't installed the big battery bank or solar panels yet, but based on preliminary testing of amps-vs-kts the numbers should be pretty close.)
>

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[Electric Boats] In praise of spares...

 

I've been running on a "zombie" controller which once died on me and then somehow came back to life (I think it re-soldered a cold-solder joint when it got hot). Yesterday, it dies completely (sparks, smoke, noise) and I'm in the middle of SF bay.

But I had a spare I bought when I thought the zombie was dead. 10 minutes later I've swapped it in and heading home. Try that with a diesel :)

I also have my batteries set up so that I can run on Bank A, Bank B or both. Bank B is only 4 old tired batteries with about 15 usable AH so I usually run on bank A (80AH). In practice I don't switch over that often - but knowing I can reduces a lot of "range anxiety". If bank B were healthy there'd be some benefit to running in both all the time, but at my normal 40amp draw it's not that significant.

Also...learning that there's more than one way to connect the chargers when running under generator. I had mine hooked up directly to the controller - so it's still paralleled in with the batteries - and in this config it would seriously lug my generator and I couldn't go much over 20amps. Connecting the leads to the batteries instead I can now pull any amps I want (assuming the batteries have some charge). I'm at a loss to explain the difference - I originally thought it was an idiosyncrasy of my charger but I've used a different one with the same results.

-Keith

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[Electric Boats] Re: Green boating near San Francisco

 

Hi Russ,

Good to know of another SF boater - so far myself, Hans, Mark, Kevin (Arby's motor) and the guy with LION whose name escapes me is all I can confirm. There's another fellow - a pioneer with a Rawson 30 named Steve but I don't think he frequents the group. I've heard of 2 or 3 other boats - including one right next to mine in Brisbane but I've never been able to contact the owner.

I won't be able to make it either being a workday, but would be interested to hear the outcome.

-Keith

--- In electricboats@yahoogroups.com, russ1302 <no_reply@...> wrote:
>
>
> I recently completed an electric conversion on my Newport 27 and would love to join you, but I'm not going to be available. Let us all know if thing like this are going to happen in the future.
> Russ
>
> --- In electricboats@yahoogroups.com, "Mark" <mstafford@> wrote:
> >
> > This is an open invite for an impromptu meeting in Richmond, CA about electric propulsion for 30' ish sailboats. Two people I ran into at KKMI boatyard need repowers, and are interested in the electric possibilities. My boat is there now, so I volunteered to meet them Monday, Dec 7th at 11:00am in the canvas shop of Durrant Designs. Anybody here is welcome to come there and participate in any manner they see fit.
> >
> > Sorry Matti, I have no airfare money for reimbursement. I'll work on that though :-)
> >
> > Manufacturers, e-boat owners, enthusiasts.... just be open about your motivations for being there and it will be a productive time.
> >
> > Sorry for the sudden notice. Look up KKMI for location. Call or email me if you wish more context or information. I have nothing to sell, and am not asking for any money.
> >
> > Mark Stafford 925-586-0839cell
> > mstafford at natca dot net
> >
>

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