Re: [bolger] Re: WATER WAGON
Not that I will claim to know much about this but
in a lecture at a cruising club the "ancient wise one" (and I mean that) who
still owns his own battery company after 50 years said that one of the
best things one can do to the batteries is give them an "equalization
charge" on a yearly ?? basis. I bought a charger that has this function at
Canadian Tire--some type of smart charger made by Shumacher for about $70
Canadian.http://www.mydrv.net/equalization.htm
I have had an older Air Marine wind charger on my
boat for 6 years and it does a good job of keeping the batteries topped up--but
that all depends on what you expect from your batteries I guess. I have 400
amp/hours of capacity and this size because when I bought the wind generator it
was the minimum size they recommended so that the charging could be accurately
assessed by the unit. This no longer applies. The noise of the 3 blade prop
drives some people crazy--but I did get used to it. Other multiblade
windchargers are much quieter. Initially I bought a 5hp Briggs and Stratton
motor and put on a larger 12Volt alternator to charge the
batteries since my 35 foot cat is powered by a 10 hp OB that only has a 25 watt
charger.
I have heard that using the prop to generate power
to recharge under way may not be very effective but have no direct experience.
The alternator on the small motor may be a way to
go until you get all the other things sorted out --one could pick up the
alternator cheap at a rebuilders and a small gas motor from a lawnmower and this
would allow you to experiment with wind generators and solar without fear of
running low. Once you have solved all the problems you could sell the motor rig
or keep it.
Regen on a sailboat is hype. It just cannot give you significant power
unless you have a powerful sailboat - like a 40 foot trimaran.
Think how your boat would sail if you had a bucket the size of your
propeller dragging behind you.
People who have tried regen say that they can’t get anything unless going
over 6 knots.
Tow-behind generators seem to work a bit better on big boats, but, any way
you work the math, a generator is going to cost 5 to 10 times more drag than you
will recover in your battery bank.
I
saw a sailboat advertised about a year ago (on sailnet, I think? could have been
elsewhere) that was set up to run on an electric motor. The motor also
acted as the generator for it's own battery's charging system when under sail;
the spinning of the prop would spin the motor, and cause it to act as a
generator. I believe the setup is available as a retail package. Of
course, it wouldn't work nearly as well for a boat that relies primarily on
engine power, instead of wind power.
I'm sure that whatever power option you choose to go with, you'll do fine. Personally, I'd worry about how well the setup would last before each time it needed to be maintained - water and electronics have had problem with each other for as long as electronics have been around, with water winning most of the time. If used in salt water, corrosion is much worse. Not to mention that, if you intend to use your boat fairly extensively whenever you do have it out, it may be impossible to "baby" the batteries to extend their lifespan. Wind generation and solar panels may help in that regard.
Good luck, however you decide to go.
I'm sure that whatever power option you choose to go with, you'll do fine. Personally, I'd worry about how well the setup would last before each time it needed to be maintained - water and electronics have had problem with each other for as long as electronics have been around, with water winning most of the time. If used in salt water, corrosion is much worse. Not to mention that, if you intend to use your boat fairly extensively whenever you do have it out, it may be impossible to "baby" the batteries to extend their lifespan. Wind generation and solar panels may help in that regard.
Good luck, however you decide to go.
I saw a sailboat advertised about a year ago (on sailnet, I think? could have been elsewhere) that was set up to run on an electric motor. The motor also acted as the generator for it's own battery's charging system when under sail; the spinning of the prop would spin the motor, and cause it to act as a generator. I believe the setup is available as a retail package. Of course, it wouldn't work nearly as well for a boat that relies primarily on engine power, instead of wind power.
I'm sure that whatever power option you choose to go with, you'll do fine. Personally, I'd worry about how well the setup would last before each time it needed to be maintained - water and electronics have had problem with each other for as long as electronics have been around, with water winning most of the time. If used in salt water, corrosion is much worse. Not to mention that, if you intend to use your boat fairly extensively whenever you do have it out, it may be impossible to "baby" the batteries to extend their lifespan. Wind generation and solar panels may help in that regard.
Good luck, however you decide to go.
I'm sure that whatever power option you choose to go with, you'll do fine. Personally, I'd worry about how well the setup would last before each time it needed to be maintained - water and electronics have had problem with each other for as long as electronics have been around, with water winning most of the time. If used in salt water, corrosion is much worse. Not to mention that, if you intend to use your boat fairly extensively whenever you do have it out, it may be impossible to "baby" the batteries to extend their lifespan. Wind generation and solar panels may help in that regard.
Good luck, however you decide to go.
I;m familiar with several sailboat conversions to electric propulsion.
One is a 36' Columbia, cruised extensively on both the east and west
coasts. the other is a restore gaff schooner locally. Both have worked
well, after the skippers have made allowances for the electric
propulsion limitations. Neither is a direct replacement for an IC
engine. There is enough power to get out of the marina and away from the
socks. Both skippers sail more than power and adjust their schedules
accordingly.
Capt'n Pauley (Paul Esterle)
Freelance Boating Writer
www.thevirtualboatyard.com
One is a 36' Columbia, cruised extensively on both the east and west
coasts. the other is a restore gaff schooner locally. Both have worked
well, after the skippers have made allowances for the electric
propulsion limitations. Neither is a direct replacement for an IC
engine. There is enough power to get out of the marina and away from the
socks. Both skippers sail more than power and adjust their schedules
accordingly.
Capt'n Pauley (Paul Esterle)
Freelance Boating Writer
www.thevirtualboatyard.com
On 6/13/2011 5:39 PM, Eric wrote:
>
> Thanks for the links.
>
> I am still considering electric propulsion. If the Torqeedo didn't
> have reliability issues, and perhaps exaggerated propulsion claims, I
> would buy one today. I will keep cobbling along for a while longer in
> hopes that a good electric solution presents itself. From what I have
> read, I believe someone could replace an inboard with an electric
> motor, reliably, today.
>
> I also appreciate the comment made in another response about
> increasing longevity of batteries by babying them. A very good idea
> given the cost of batteries. The longer they last, the more economical
> and practical an investment they will be.
> Eric
>
Thanks for the links.
I am still considering electric propulsion. If the Torqeedo didn't have reliability issues, and perhaps exaggerated propulsion claims, I would buy one today. I will keep cobbling along for a while longer in hopes that a good electric solution presents itself. From what I have read, I believe someone could replace an inboard with an electric motor, reliably, today.
I also appreciate the comment made in another response about increasing longevity of batteries by babying them. A very good idea given the cost of batteries. The longer they last, the more economical and practical an investment they will be.
Eric
I am still considering electric propulsion. If the Torqeedo didn't have reliability issues, and perhaps exaggerated propulsion claims, I would buy one today. I will keep cobbling along for a while longer in hopes that a good electric solution presents itself. From what I have read, I believe someone could replace an inboard with an electric motor, reliably, today.
I also appreciate the comment made in another response about increasing longevity of batteries by babying them. A very good idea given the cost of batteries. The longer they last, the more economical and practical an investment they will be.
Eric
--- Inbolger@yahoogroups.com, "F Neil Simms" <f.neil.simms@...> wrote:
>
> I've seen several sellers of Thundersky (Winston) LiFePO4 batteries at that price per watt. Here are a couple:
>
>http://currentevtech.com/Lithium-Batteries/Thundersky-c11/
>http://www.evolveelectrics.com/Thunder%20Sky%20Lithium%20Batteries.html
>
> All sort of great claims as to longevity, but only time will tell (they SHOULD be considerably longer lived than lead acid when driven to 80% discharge, and if care is taken when charging them).
>
> It's becoming more practical and affordable by the day to go electric, and a lot of Bolger designs lend themselves to it. I hope we some more builds going in this direction.
>
>
> --- Inbolger@yahoogroups.com, "Eric" <eric14850@> wrote:
> >
> > Where are you buying your LiFePO4? What sort of life expectancy can be expected?
> >
> > I have a 2001 Prius I bought with 103,000 miles on it three years ago. It now has 170,000 miles. The list value of the care diminished radically over those three years presumably because of fear about how long the drive battery will last. I judge it to be as good as it was three years ago based on fuel milage which has not changed.
> >
> > Eric
> >
> >
> >
> > --- Inbolger@yahoogroups.com, "F Neil Simms" <f.neil.simms@> wrote:
> > >
> > >
> > >
> > > --- Inbolger@yahoogroups.com, Pierce Nichols <rocketgeek@> wrote:
> > >
> > > > Where 'the future' is next year. The market for batteries is changing fast
> > > > right now. A bit of googling tells me that the retail cost of LiPo packs is
> > > > around $1/Wh retail.
> > >
> > > If you are willing to build your own battery pack, LiFePO4 is more like $0.40/Wh at this point - I'm currently looking at 100 Ah cells (3.2v, = 320 Wh) for $125 plus domestic shipping...
> > >
> > > The ideal Bolger designs that can take advantage of this improving electric storage technology are the longer and narrower displacement or semi-displacement hulls, particularly those that lend themselves to mounting solar arrays. I'm starting a build of a multipurpose 24' trimaran for electric propulsion, with a removable solar hardtop (as it's also configurable as a cat-ketch coastal expedition boat). My own design, but heavily influenced by previous Bolger builds and his general sensibility WRT light, stitch and glue camp-cruisers.
> > >
> > > I think we're on the cusp of a major shift toward electric small boats, and I wish Phil was still around to help it along...
> > >
> >
>
You should find articles on the RAV4E. Those were sold when they came off lease. They sold for near $50,000 each. The expected battery life was 6 years. They have gone 9 now and still seem to be good. Part of this is that they were used in utility fleets and so had regular maintenance like being charged every day.
MylesJ
Priuses use nickel metal hydride batteries. Toyota wisely chose to treat
the Prius batteries with kid gloves -- the batteries are never charged
more than 90-some-odd percent, and they're never discharged very much.
They could have got better mileage by working the batteries harder, but at
the risk of shorter battery pack life. I think it was a good trade-off.
I've got a 2005 Prius with a bit over 50,000 trouble free miles so far.
I'm pleased to see that Eric has gone more than three times that without
battery deterioration.
The lesson electric boaters could learn from Toyota is to size your
battery bank so you can get the range and performance you need without
stressing the batteries, whatever type you use, and use a good charging
system that never overcharges the batteries.
the Prius batteries with kid gloves -- the batteries are never charged
more than 90-some-odd percent, and they're never discharged very much.
They could have got better mileage by working the batteries harder, but at
the risk of shorter battery pack life. I think it was a good trade-off.
I've got a 2005 Prius with a bit over 50,000 trouble free miles so far.
I'm pleased to see that Eric has gone more than three times that without
battery deterioration.
The lesson electric boaters could learn from Toyota is to size your
battery bank so you can get the range and performance you need without
stressing the batteries, whatever type you use, and use a good charging
system that never overcharges the batteries.
On Sat, 11 Jun 2011 18:08:36 -0700, Eric <eric14850@...> wrote:
> Where are you buying your LiFePO4? What sort of life expectancy can be
> expected?
>
> I have a 2001 Prius I bought with 103,000 miles on it three years ago.
> It now has 170,000 miles. The list value of the care diminished
> radically over those three years presumably because of fear about how
> long the drive battery will last. I judge it to be as good as it was
> three years ago based on fuel milage which has not changed.
--
John (jkohnen@...)
Eels are said to kelter in the water when they wamble.
I've seen several sellers of Thundersky (Winston) LiFePO4 batteries at that price per watt. Here are a couple:
http://currentevtech.com/Lithium-Batteries/Thundersky-c11/
http://www.evolveelectrics.com/Thunder%20Sky%20Lithium%20Batteries.html
All sort of great claims as to longevity, but only time will tell (they SHOULD be considerably longer lived than lead acid when driven to 80% discharge, and if care is taken when charging them).
It's becoming more practical and affordable by the day to go electric, and a lot of Bolger designs lend themselves to it. I hope we some more builds going in this direction.
http://currentevtech.com/Lithium-Batteries/Thundersky-c11/
http://www.evolveelectrics.com/Thunder%20Sky%20Lithium%20Batteries.html
All sort of great claims as to longevity, but only time will tell (they SHOULD be considerably longer lived than lead acid when driven to 80% discharge, and if care is taken when charging them).
It's becoming more practical and affordable by the day to go electric, and a lot of Bolger designs lend themselves to it. I hope we some more builds going in this direction.
--- Inbolger@yahoogroups.com, "Eric" <eric14850@...> wrote:
>
> Where are you buying your LiFePO4? What sort of life expectancy can be expected?
>
> I have a 2001 Prius I bought with 103,000 miles on it three years ago. It now has 170,000 miles. The list value of the care diminished radically over those three years presumably because of fear about how long the drive battery will last. I judge it to be as good as it was three years ago based on fuel milage which has not changed.
>
> Eric
>
>
>
> --- Inbolger@yahoogroups.com, "F Neil Simms" <f.neil.simms@> wrote:
> >
> >
> >
> > --- Inbolger@yahoogroups.com, Pierce Nichols <rocketgeek@> wrote:
> >
> > > Where 'the future' is next year. The market for batteries is changing fast
> > > right now. A bit of googling tells me that the retail cost of LiPo packs is
> > > around $1/Wh retail.
> >
> > If you are willing to build your own battery pack, LiFePO4 is more like $0.40/Wh at this point - I'm currently looking at 100 Ah cells (3.2v, = 320 Wh) for $125 plus domestic shipping...
> >
> > The ideal Bolger designs that can take advantage of this improving electric storage technology are the longer and narrower displacement or semi-displacement hulls, particularly those that lend themselves to mounting solar arrays. I'm starting a build of a multipurpose 24' trimaran for electric propulsion, with a removable solar hardtop (as it's also configurable as a cat-ketch coastal expedition boat). My own design, but heavily influenced by previous Bolger builds and his general sensibility WRT light, stitch and glue camp-cruisers.
> >
> > I think we're on the cusp of a major shift toward electric small boats, and I wish Phil was still around to help it along...
> >
>
Where are you buying your LiFePO4? What sort of life expectancy can be expected?
I have a 2001 Prius I bought with 103,000 miles on it three years ago. It now has 170,000 miles. The list value of the care diminished radically over those three years presumably because of fear about how long the drive battery will last. I judge it to be as good as it was three years ago based on fuel milage which has not changed.
Eric
I have a 2001 Prius I bought with 103,000 miles on it three years ago. It now has 170,000 miles. The list value of the care diminished radically over those three years presumably because of fear about how long the drive battery will last. I judge it to be as good as it was three years ago based on fuel milage which has not changed.
Eric
--- Inbolger@yahoogroups.com, "F Neil Simms" <f.neil.simms@...> wrote:
>
>
>
> --- Inbolger@yahoogroups.com, Pierce Nichols <rocketgeek@> wrote:
>
> > Where 'the future' is next year. The market for batteries is changing fast
> > right now. A bit of googling tells me that the retail cost of LiPo packs is
> > around $1/Wh retail.
>
> If you are willing to build your own battery pack, LiFePO4 is more like $0.40/Wh at this point - I'm currently looking at 100 Ah cells (3.2v, = 320 Wh) for $125 plus domestic shipping...
>
> The ideal Bolger designs that can take advantage of this improving electric storage technology are the longer and narrower displacement or semi-displacement hulls, particularly those that lend themselves to mounting solar arrays. I'm starting a build of a multipurpose 24' trimaran for electric propulsion, with a removable solar hardtop (as it's also configurable as a cat-ketch coastal expedition boat). My own design, but heavily influenced by previous Bolger builds and his general sensibility WRT light, stitch and glue camp-cruisers.
>
> I think we're on the cusp of a major shift toward electric small boats, and I wish Phil was still around to help it along...
>
--- Inbolger@yahoogroups.com, Pierce Nichols <rocketgeek@...> wrote:
The ideal Bolger designs that can take advantage of this improving electric storage technology are the longer and narrower displacement or semi-displacement hulls, particularly those that lend themselves to mounting solar arrays. I'm starting a build of a multipurpose 24' trimaran for electric propulsion, with a removable solar hardtop (as it's also configurable as a cat-ketch coastal expedition boat). My own design, but heavily influenced by previous Bolger builds and his general sensibility WRT light, stitch and glue camp-cruisers.
I think we're on the cusp of a major shift toward electric small boats, and I wish Phil was still around to help it along...
> Where 'the future' is next year. The market for batteries is changing fastIf you are willing to build your own battery pack, LiFePO4 is more like $0.40/Wh at this point - I'm currently looking at 100 Ah cells (3.2v, = 320 Wh) for $125 plus domestic shipping...
> right now. A bit of googling tells me that the retail cost of LiPo packs is
> around $1/Wh retail.
The ideal Bolger designs that can take advantage of this improving electric storage technology are the longer and narrower displacement or semi-displacement hulls, particularly those that lend themselves to mounting solar arrays. I'm starting a build of a multipurpose 24' trimaran for electric propulsion, with a removable solar hardtop (as it's also configurable as a cat-ketch coastal expedition boat). My own design, but heavily influenced by previous Bolger builds and his general sensibility WRT light, stitch and glue camp-cruisers.
I think we're on the cusp of a major shift toward electric small boats, and I wish Phil was still around to help it along...
The Torgeedo web site has accurate charts of what to expect with their motors and battery combinations.
I own a Torqeedo 1003 which I use on a 16 foot dingy. What I get is what they say I should get in their chart:
http://www.torqeedo.com/us/hn/products/travel-503-1003/on-the-move-speed-range-run-time.html
It's going to look like an expensive choice until you balance true costs. I think my motor would work fine for a Birdwatcher where you want to get home from 5 miles out.
The trick is to understand that you should not expect to be able to get anywhere near hull speed unless you want to drain the batteries in less than 5 miles. But you can get one-third hull speed for many hours.
I own a Torqeedo 1003 which I use on a 16 foot dingy. What I get is what they say I should get in their chart:
http://www.torqeedo.com/us/hn/products/travel-503-1003/on-the-move-speed-range-run-time.html
It's going to look like an expensive choice until you balance true costs. I think my motor would work fine for a Birdwatcher where you want to get home from 5 miles out.
The trick is to understand that you should not expect to be able to get anywhere near hull speed unless you want to drain the batteries in less than 5 miles. But you can get one-third hull speed for many hours.
--- Inbolger@yahoogroups.com, "Chester Young" <chester@...> wrote:
>
> I am curious about the potential range of a battery system. My Uncle
> has a birdwatcher and he is determined to change to an electric
> auxiliary. It is easy to get 5 miles from home were we are
> (Caloosahatchee River) and have the wind either die or blow right on the
> nose. How far can a person really expect to motor a boat under just
> minimally adverse conditions? For this discussion lets consider three
> deep cycle batteries, that would be a lot of weight relative to a bird
> watcher and a considerable bit of space too.
>
>
>
> ~Caloosarat
>
>
>
> From:bolger@yahoogroups.com[mailto:bolger@yahoogroups.com] On Behalf
> Of BruceHallman
> Sent: Friday, June 03, 2011 1:31 PM
> To:bolger@yahoogroups.com
> Subject: Re: [bolger] Re: WATER WAGON
>
>
>
>
>
> On Fri, Jun 3, 2011 at 10:09 AM, Pierce Nichols <rocketgeek@...
> <mailto:rocketgeek%40gmail.com> > wrote:
> >
> >
> >
> > The wide availability of lithium polymer (LiPo) packs has changed that
> equation somewhat.
>
> Perhaps in the future. I believe that presently LiPo are proving
> economical only on small scale, like with model airplanes, and
> bicycles which both are weight sensitive making paying the bucks to
> save the weight worthwhile.
>
> On a displacement powerboat you can have the weight luxury of using
> more economical lead acid batteries.
>
> I suppose if you were developing an electric boat to plane you could
> justify LiPo, but if that were the case, I don't think you want it to
> also be a camper like WaterVan.
>
How big is the proposed auxiliary? Divide the number of watt hours in the battery pack (around 1900 in the described pack) by the number of watts the motor draws (just volts times amps, since it's DC) at a given throttle setting and that tells you the maximum time you can run at that setting..
-p
-p
On Fri, Jun 3, 2011 at 11:51 AM, Chester Young<chester@...>wrote:I am curious about the potential range of a battery system. My Uncle has a birdwatcher and he is determined to change to an electric auxiliary. It is easy to get 5 miles from home were we are (Caloosahatchee River) and have the wind either die or blow right on the nose. How far can a person really expect to motor a boat under just minimally adverse conditions? For this discussion lets consider three deep cycle batteries, that would be a lot of weight relative to a bird watcher and a considerable bit of space too.
~Caloosarat
From:bolger@yahoogroups.com[mailto:bolger@yahoogroups.com]On Behalf OfBruceHallman
Sent:Friday, June 03, 2011 1:31 PM
To:bolger@yahoogroups.com
Subject:Re: [bolger] Re: WATER WAGON> The wide availability of lithium polymer (LiPo) packs has changed that equation somewhat.Perhaps in the future. I believe that presently LiPo are proving
economical only on small scale, like with model airplanes, and
bicycles which both are weight sensitive making paying the bucks to
save the weight worthwhile.
On a displacement powerboat you can have the weight luxury of using
more economical lead acid batteries.
I suppose if you were developing an electric boat to plane you could
justify LiPo, but if that were the case, I don't think you want it to
also be a camper like WaterVan.
On Fri, Jun 3, 2011 at 10:26 AM, BruceHallman<hallman@...>wrote:On Fri, Jun 3, 2011 at 10:09 AM, Pierce Nichols <rocketgeek@...> wrote:Perhaps in the future. I believe that presently LiPo are proving
>
>
>
> The wide availability of lithium polymer (LiPo) packs has changed that equation somewhat.
economical only on small scale, like with model airplanes, and
bicycles which both are weight sensitive making paying the bucks to
save the weight worthwhile.
Where 'the future' is next year. The market for batteries is changing fast right now. A bit of googling tells me that the retail cost of LiPo packs is around $1/Wh retail. Good deep cycle lead acid batteries (Optima, for example) are around $0.30/Wh retail. That LiPo price is probably high of what you'd pay for outfitting an electric boat, since it's based on relatively small packs (20 - 30 Wh) and the lead acid price is based on standard 12V marine batteries (600 - 700 Wh). That's down significantly from the last time I checked, a few months ago.On a displacement powerboat you can have the weight luxury of using
more economical lead acid batteries.
I suppose if you were developing an electric boat to plane you could
justify LiPo, but if that were the case, I don't think you want it to
also be a camper like WaterVan.
I believe the WaterVan is intended to plane... certainly at least one of them is powered for that.
-p
The Bolger article to look up is Vol14 No22, you could get a reprint
from Bob Hicks. In that article PCB/SA go on at length describing
their process designing the battery system for their electric launch
Lily. It is far from simple, requiring a balance of amp hour rating
with motor, and then isolating the batteries with diodes and designing
the charging system. Lily settled on 6 each Catagory 27 12V batteries
weighing a total of 330lbs, and providing 350 amp-hours at 24V. The
charging system is not trivial because it is not uncommon to only have
available one 15Amp circuit of 110V power.In the end, PCB/SA settled
on having six dedicated chargers, one each for each battery in the
bank; all necessary to achieve a recharge within a reasonable time
period.
from Bob Hicks. In that article PCB/SA go on at length describing
their process designing the battery system for their electric launch
Lily. It is far from simple, requiring a balance of amp hour rating
with motor, and then isolating the batteries with diodes and designing
the charging system. Lily settled on 6 each Catagory 27 12V batteries
weighing a total of 330lbs, and providing 350 amp-hours at 24V. The
charging system is not trivial because it is not uncommon to only have
available one 15Amp circuit of 110V power.In the end, PCB/SA settled
on having six dedicated chargers, one each for each battery in the
bank; all necessary to achieve a recharge within a reasonable time
period.
On Fri, Jun 3, 2011 at 11:51 AM, Chester Young <chester@...> wrote:
>
>
>
> I am curious about the potential range of a battery system. My Uncle has a birdwatcher and he is determined to change to an electric auxiliary. It is easy to get 5 miles from home were we are (Caloosahatchee River) and have the wind either die or blow right on the nose. How far can a person really expect to motor a boat under just minimally adverse conditions? For this discussion lets consider three deep cycle batteries, that would be a lot of weight relative to a bird watcher and a considerable bit of space too.
>
>
>
> ~Caloosarat
I am curious about the potential range of a battery system. My Uncle has a birdwatcher and he is determined to change to an electric auxiliary. It is easy to get 5 miles from home were we are (Caloosahatchee River) and have the wind either die or blow right on the nose. How far can a person really expect to motor a boat under just minimally adverse conditions? For this discussion lets consider three deep cycle batteries, that would be a lot of weight relative to a bird watcher and a considerable bit of space too.
~Caloosarat
From:bolger@yahoogroups.com [mailto:bolger@yahoogroups.com]On Behalf OfBruceHallman
Sent:Friday, June 03, 2011 1:31 PM
To:bolger@yahoogroups.com
Subject:Re: [bolger] Re: WATER WAGON
On Fri, Jun 3, 2011 at 10:09 AM, Pierce Nichols <rocketgeek@...> wrote:
>Perhaps in the future. I believe that presently LiPo are proving
>
>
> The wide availability of lithium polymer (LiPo) packs has changed that equation somewhat.
economical only on small scale, like with model airplanes, and
bicycles which both are weight sensitive making paying the bucks to
save the weight worthwhile.
On a displacement powerboat you can have the weight luxury of using
more economical lead acid batteries.
I suppose if you were developing an electric boat to plane you could
justify LiPo, but if that were the case, I don't think you want it to
also be a camper like WaterVan.
On Fri, Jun 3, 2011 at 10:09 AM, Pierce Nichols <rocketgeek@...> wrote:
economical only on small scale, like with model airplanes, and
bicycles which both are weight sensitive making paying the bucks to
save the weight worthwhile.
On a displacement powerboat you can have the weight luxury of using
more economical lead acid batteries.
I suppose if you were developing an electric boat to plane you could
justify LiPo, but if that were the case, I don't think you want it to
also be a camper like WaterVan.
>Perhaps in the future. I believe that presently LiPo are proving
>
>
> The wide availability of lithium polymer (LiPo) packs has changed that equation somewhat.
economical only on small scale, like with model airplanes, and
bicycles which both are weight sensitive making paying the bucks to
save the weight worthwhile.
On a displacement powerboat you can have the weight luxury of using
more economical lead acid batteries.
I suppose if you were developing an electric boat to plane you could
justify LiPo, but if that were the case, I don't think you want it to
also be a camper like WaterVan.
The wide availability of lithium polymer (LiPo) packs has changed that equation somewhat. I've seen quoted energy densities in the range of 135 Wh/kg vs 30-40 Wh/kg for lead-acid.
That means that the current energy density for LiPos is about 1/9th that of gasoline... but 85%-90% of that is available at the prop shaft vs 15%-20% (or less) for a conventional gas or diesel motor. Given that electric motor systems (motor + gearbox + controls) are now smaller and lighter than gas or diesel systems of equivalent delivered power. That means that for some applications, the all-up weight of an electric system could potentially be less than that of a conventional system.
I've done some desultory investigation (i.e. confirming I'm not insane) into the possibility of integrating an outrunner brushless electric motor into the hub of a prop. No stuffing box, no gears, everything sealed and potted, the prop itself is both part of the motor and the only moving part in the system. With some added cleverness, you could even have the prop stop immediately in the event that it contacted anything, which would improve safety for boaters and wildlife.
-p
That means that the current energy density for LiPos is about 1/9th that of gasoline... but 85%-90% of that is available at the prop shaft vs 15%-20% (or less) for a conventional gas or diesel motor. Given that electric motor systems (motor + gearbox + controls) are now smaller and lighter than gas or diesel systems of equivalent delivered power. That means that for some applications, the all-up weight of an electric system could potentially be less than that of a conventional system.
I've done some desultory investigation (i.e. confirming I'm not insane) into the possibility of integrating an outrunner brushless electric motor into the hub of a prop. No stuffing box, no gears, everything sealed and potted, the prop itself is both part of the motor and the only moving part in the system. With some added cleverness, you could even have the prop stop immediately in the event that it contacted anything, which would improve safety for boaters and wildlife.
-p
On Fri, Jun 3, 2011 at 9:19 AM, BruceHallman<hallman@...>wrote:Judging from the other Bolger designs with massive electric banks,
they need to be designed to accommodate the additional displacement
caused by the weight of the batteries. I doubt that trying to
retrofit the Watervan design to electric power would be satisfying.
That design relies on having relatively light weight in order to not
float too deeply in the water.
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Judging from the other Bolger designs with massive electric banks,
they need to be designed to accommodate the additional displacement
caused by the weight of the batteries. I doubt that trying to
retrofit the Watervan design to electric power would be satisfying.
That design relies on having relatively light weight in order to not
float too deeply in the water.
they need to be designed to accommodate the additional displacement
caused by the weight of the batteries. I doubt that trying to
retrofit the Watervan design to electric power would be satisfying.
That design relies on having relatively light weight in order to not
float too deeply in the water.
If you mean the Watervan as someone else suggested, you'd need to ask Suzanne. The plans call for a 45-90HP outboard. I've seen 13HP electric outboards that could run from 48 volts, use big wires. On the other hand electric motors have max torque at 0 rpm, so an electric motor under 45hp might work to give you enough speed for your application.
--- Inbolger@yahoogroups.com, "hightop32736" <bayfield@...> wrote:
>
> Could the "Waterwagon " design be converted to an electric boat with batteries and motor in the cutwater bilge and solar panels on the roof. It looks very doable, any comments?
>
Anything is possible, but---
Waterwagon (I think PCB called it Watervan) was designed as a planing hull and it is unlikely that current electric technology can produce a power to weight ratio anywhere close to a gas outboard.
Perhaps a better choice would be something like Becky Thatcher. You might want to take a look at Lily, particularly the very deep rocker on the bottom necessary to float the weight of passengers and batteries. If you wanted to modify a Waterwagon for electric power and low speed use, you would need to build a lot of rocker into the bottom to support the weight and keep the transom from dragging. I believe that this sort of thing is more fun to think about than to actually attempt.
JohnT
From:bolger@yahoogroups.com [mailto:
bolger@yahoogroups.com ]On Behalf Ofhightop32736
Sent:Thursday, June 02, 2011 8:25
PM
To:bolger@yahoogroups.com
Subject:[bolger] WATER WAGON
Could the "Waterwagon " design be converted to an electric boat with batteries and motor in the cutwater bilge and solar panels on the roof. It looks very doable, any comments?
--- Inbolger@yahoogroups.com, "hightop32736" <bayfield@...> wrote:
http://www.duckworksmagazine.com/06/gatherings/kingston/index.htm
>"Watervan", perhaps? [about halfway down this page]:
> Could the "Waterwagon " design be converted to an electric boat...
http://www.duckworksmagazine.com/06/gatherings/kingston/index.htm
I'm not aware of a Bolger design with that name. Please show it if there is one.
Is this your boat?
That's kinda big, broad, heavy and with a lot of windage for an electric. It could be done, though with any hull's typical limit of being able to carry enough batteries to last about half a day ( before you need a bigger motor to move it all and then need batteries still more ), it's a big, expensive project for going short distances.
There are scenarios where it'd work, maybe some canal system with frequent charge facilities.
You must read Douglas Little'sElecric Boats, wherever it can be found now. And if you haven't already, check in here:
Mark
On Jun 2, 2011, at 5:24 PM, hightop32736 wrote:
Could the "Waterwagon " design be converted to an electric boat with batteries and motor in the cutwater bilge and solar panels on the roof. It looks very doable, any comments?
Could the "Waterwagon " design be converted to an electric boat with batteries and motor in the cutwater bilge and solar panels on the roof. It looks very doable, any comments?