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No problem always glad to help. I hope you got their web site <br> www.sdp-si.com<br><br>Don

Thanks for the info donaldbaer.

There's a company called Stock Drive Products. I am sure they have hwta you need. You can reach them at www.sdp-si.com<br><br>Good luck<br><br>Don

Has anyone built the Marina R/C by Artesania
Latina? I am and the building part is no problem. I cant
find drive linkage. The ship kit came with the
stuffing box with prop and shaft. The company I bought the
kit from I wont mention any names. Sold me an
electric motor. I thought I was getting everything I
needed for the kit. I need a drive linkage like a U
joint or pin joint. I have searcher all over the web
for model companies if they sell anything. I have had
no luck yet.<br> The motor shaft is 1/8 or 3mm. The
prop shaft is 5/32 or 4mm. On the plans it shows a
gear reduction with a linkage on it. I will settle for
just a linkage at this point. I am hoping someone has
some info to where I may be able to find something
that may work. <br> Thanks

Donald...you have misunderstood what I was
saying. You are right on some points...the battery amp
hours dont change, HOWEVER, there ability to deliver
200 amps does and some deep cycle batteries dont like
200 amp draws when they are fully charged. Yes, you
still need the same number of batteries but the
continuous amperage draw is reduced to a lower number (30
amps) that allows access to more of those amp hours and
is less damaging when the batteris are run below 50%
of their available amp hours. Forgive me fer
mentionin' it but I thought most of the electric cars were
3phase PWM and all over 200 volts...the GM Impact is 360
Volts DC fer shure. As far as regenerative feedback
goes..I think the techniques for using a brushed motor
and the pole structure on a single phase low voltage
PWM motor with less that 24 poles would prevent you
from recouping any meaningful regen anyway...that is
even if my patents weren't international.
Besides..have you seen a 200 amp motor that was sealed and
didnt have to use salty bilge air for internal cooling
? What affect does salty bilge air have on brushes
? Dont brushes make a lot of sparks in that
unsealed casing ? What affect does damp bilge air have on
NDBoron magnets and copper windings ? Do these motors
have thrust bearings to handle prop thrust and loading
? If 15" to 20" props spin at 700 to 1000 RPM's,
wouldnt it be better to use a motor that is designed for
that range.<br> Yes..you can go cheap and stick some
off-the-shelf motor in your boat..but why would you..especially
is you have just spent 30 to 80 thousand dollars.

I came into this forem with the thought that high
voltage systems would be the way to go and actualy did
several design looking at several brushless technologies
to try to come up with a more cost effective design.
I felt that you could get more battery life (longer
range) by using higher voltage. After contacting a
number of different Battery manufacturers (Lead acid,
sealed lead acid, lead calcium, NiMh, and Lithium
Polimer) I came to one conclusion. It doesn't matter if
you connect he batteries in series for higher voltage
or parrallel for higher current capacity The
Watts/KG are the same you are going to need just as many
batteries no matter how there connected. It is still true
also that DC brushed motor offer the least costly
technology for electric propulsion. The EV guys who are
spending a lot of money on this research have come to the
same conclusion. Thats why International Rectifier,
GE, ABB,Siemans and many other semi conductor
manufacturers are no either working on or have comeout with LOW
COST high current chips that operate on less than 100
Volts. You can now buy for very little money high
current controls that will develop up to 20 HP for well
under $1000. I am presently testing a Full H bridge
controller that will run on 24-72 Volts and provide 200 amps
on continuous current. this control provides solid
state reversing AND regeneration and cost between $600
and $800<br>That means one can now put a 10 HP Motor
and controller in their boat to replace there 30 Hp
gasoline engine and do it for less than $3000 including
motor. And they can charge there batteries while under
sail. <br> Unfortunatly DC Brushles and AC propulsion
units are still far more costly than that. it's a
matter of economics.

You got it Larry,<br>When you discharge your
batteries it's hopefully not to 100% DOD, but counting the
losses 240 ah is a good number to use. The rest is
correct and should work out to around a buck your
cost...<br>BTW, ain't it great, we can cruise around for the
whole day on a buck. ICE cost are 10~15 time
that.<br>Joe

OK, guys, check my math on this.<br>Thanks for
the suggestion, Joe, although I have the problem that
my charger is automatic and therefore its draw
varies over time and Im usually not able to monitor it
closely enough to determine how long its run anyway. But
how about this:<br><br>If P (power in W)= V (voltage)
X A (amperage) then my 240AH battery bank converts
to (36 X 240) 8,640 watt-hours or 8.64KWH. Assuming
something like 60% charging efficiency, as Joe pointed out,
a full replacement of the bank would require 14.4
KWH. If electricity costs $.06/kwh then a complete
replacement of the bank would cost.$.86. Is that really
right?!<br><br>Based on my limited tests so far it looks more typical
that my boat will cruise most efficiently at about
4.3mph at 1 hp (20.8A). At that rate a 20 mi. cruise
would cost $.35.<br><br>Tell me this is right or at
least close.<br><br>Larry

Corrosion resistance and resistance to
electrolysis can be designed into the system by electically
isolating the system. On PM DC motors the torque curve is
not a curve at all but instead they have a torque
plateau.This is to say that the motors are capable of the same
torque at 1 rpm as they are at 1000 rpm's. Heat is no
problem in a properly designed system with motors that
have a total system eff of 90% or better. In reference
to you other statement/question 7,500 rpms is a bit
high with lower units usually having a 2 to 3 :1 gear
ratio.The motor would never get to its normally most
efficient upper 3/4's of rpm range. RPM is key...and for
pushing props...the lower the better.<br> As for the next
online chat...Im ready whenever any one else is....as a
matter of fact I think I will be hangin' around in the
chat room Wed night from 8:00 to 10:00 PM East time.
And mabey every Wed night for a while ! See yall on
line.

Technically speaking.. PM DC magnet motors for 24
or 36 volts dont work either because of the current
required to make the torque. But then too,why would you
want to when higher voltage motors are so much more
efficient and you can achieve the same battery pack energy
desnsity. Current and Voltage are inversly proportional in
the KW formula ( V * A = Watts).To produce 4 KW of
power at 24 volts requires 167 amps (24*167=approx
4KW). Those amperages are just too high, produce to
much heat to dissapate and are too hard on batteries.
The key is to find a motor that runs on 120, 144 or
higher VDC and wire the batteries in series instead of
parallel yielding the same battery weight. At 144 VDC you
only need 28 amps...Ahhh..now thats a reasonable
ammount of amperage..instead of using some great weight
golf cart batteries you can use group 24 wheel chair
batteries or 27s or 31s.At 28 amps the current draw is low
enough that you can access 80 percent of most flooded
cell battery's amp hours, the efficiencies are at or
over 90% total system efficiency and the wires are
much smaller with less waste. You have the same
ammount of weight but more available power. The other
compelling factor is regenerative feedback. This really
doesnt work with any other motors except PM DC motors at
higher voltage and allows the sailboat to recharge
itself while undersail. The other important factor is
RPM and survivability in the marine environment.
Taking something off the shelf usually implies, except
for EWheels of course, a motor that was designed for
some other application that may not handle the rigors
of salty wet damp air which is needed for cooling.
Actually, that is also the compelling reason to keep those
shunt and series wound DC motors out of yer boat.

Hi Larry,<br>I beleive the two numbers you have
to find are:<br>Charger efficiency (in %) and
Battery charge acceptance (in %). Normal numbers look
like 15~20% loss at the charger (Heat) and 25% +/- 10%
for batteries (Flooded). Some battery types accept
the charge better then others (AGM and Nicad over
Flooded) As far as converting DC watts to AC watts it's
all the same. <br><br>15 amps X 36 volts = 540 watts
for 10 hours, gives 5.4kw add the 40% (540*.4) loss
of 216 watts = 7.56 Kw.(AC used). This should be
correct if the data comes from your e-meter. If the data
comes from you charger's meter you don't know what got
into the battery, so just use the loss for the charge.
The above is just an example.(try it with your
numbers)<br>Good luck <br>Joe

If I know how many DC amp hours at 36V I need to replace into my battery bank, is there a way to calculate the number of AC KW hours my charger will use in order to do it?<br><br>Thanks,<br>Larry

I received the following message and hope that
members of the club can respond directly to this 7th
grader. Paul<br><br>Hello,<br><br>My name is Dawn Martin
I am a 7th grader working on a solar powered boat
for my science fair project. My boat is a 16 foot Big
Glider model from Folbot. I have a solarex lite 30 watt
panel. I need some guidance on selection of a trolling
motor and an airplane prop for higher speed/lower
energy consumption. (reply to:
gmartin41@...)<br>Thank you.

A 27 inch ULS outboard has been on board 5 years
after 15 years with sails only. It was added at
purchase to negotiate marinas and assist anchor retrieval
so the 9.9 HP is the bare minimum and not to punch
thru storms or 200 mile becalmings. However it could
push the 50 ft, 5 tonne vessel at 8 kn in still
conditions while new.<br>Now the motor is tired, needs
expensive parts and is not powerful enough for some
situations. 20 HP is perfect for me - most 30 ft cats use two
of these 9.9s and are comparable to my boat!
Obviously i don't even enjoy having one noise maker.<br>As
i have had interest in deisel-electric in
submarines,trains,dump trucks etc. i thought it could work in boats to
get the Volts up and the Amps down. However the
danger, the weights and the need of a big smelly deisel
turned me away.<br>As i only require 20-30 minutes of
power to get to open water and the wind i turn towards
battery power with a 3 kVA generator to pump up the
batteries if sun, tow-behind or wind generators are
insufficient to charge while i'm out. There's always mains
power at marinas, but i'm on a swing
mooring.<br>Looking forward to a Solomon web page as the two-way
electron flow is what i seek! I usually have speed for
charging.<br>I seek a flat disc-shaped motor (Premag HV style)
to replace the petrol portion of my Yamaha 9.9 and
see no huge obstacles, just questions.<br>Can
corrosion resistance be retro-fitted?<br>Does a low rev
torque emphasis (for cars) preclude top-end torque or
other qualities?<br>Is heat from inefficiency margin
terminal if kept inside an outboard casing?<br>When i read
that a 2.5 inch thick, 10 inch diameter, 72 V motor
putting out 8 kW at 7,500 rpm i think why isn't there a
motor of this ilk sitting on top of my leg?<br>My
experience in EBs is limited to a rechargable drill
conversion for a canoe - works well. I plan to use gel
cells, a walk behind golf buggy motor with controller
for a small beach cat - as a tender.<br>So far i'm
enjoying this club, EVA and EBAA and gradually expanding
the base.<br>I'm developing a photo album of my
sailing boat at <a href= target=new></a>

I believe that the speed limit you refer to is
based on mono hulls and also is limited to displacement
hulls. I agree that cats and even tri hull will have
high speeds. I don't think this area has been studied
enough in this forum. I would be interested in hearing
about the performance of any multi hulls under electric
power.<br> Are you using an outboard or an inboard drive.

You and others are probably all asleep - i'm in
my lunch hour. Maybe i'll have smoko (tea-break)
when you next chat. I read last 120 messages - only
saw one "Cat" reference. I have a 50 ft Atlantic Proa
(an outrigger to the unconverted) and the 9.9 HP
outboard needs replacing. I like the technical stuff, but
enjoy it more if it is exactly correct - my theoretical
limit is 9 kn so the impossible 18 kn i do on a good
reach simply means i drag a lot of water along for the
ride. I seek the hybrid solution as i need only power
in and out of port/mooring. I'll point you to some
pictures next time....

We can do a chat in a number of ways. One is for
someone to volunteer to lead a specific topic - another
is to just set a data - see who shows up and discuss
what people want to discuss. I am open either way.
Since I couldn't get on last time - perhaps my own
bumbling fault - I can not guarantee to be able the next
time. However, Iwould be available Feb 28th, and any
day the week of March 6th. It appears that the 8-10
pm EST slot was good for everyone? If someone does
not step forward - I will pick a date by the end of
the week - and we shall see what happens. Paul

There are various kinds of "wound field motors"
first of all there is the simple shunt wound motor and
it has torque charcteristics similar to a PM DC
Motor The only real difference is that you need to
supply a shunt wound motor with a fixed voltage prior to
putting voltage on the armature. There is another kind of
wound field motor called a series wound DC motor. These
have very high starting torque but are not as
effecient as the PM or wound field motors. Traction motors
are a kind of a series wound motor and are typicaly
used on a Electric vehicles because they need a lot of
torque to get the vehicle rolling. Marine application
especialy propulsion don't need this high starting torque
since the load varies with the rpm of the propeller. It
starts out low and increases with RPM's. I am a strong
proponent for PM DC motors for marine propulsion due to the
higher effecencies. If you can gain a 10% increase in
eff at 3 Hp you will get about another hour of
cruising time out of the batteries. Unfortunatly it is
hard to get the higher powered DC Motor above 3 HP
that are made for the low voltage 24-36 Volts that
many people are running. I am in contact with a few
motor manufacturers now and hope to have information I
can share soon about some larger power PM DC motors
up to 10 Hp I hope.

Looking at DC electric motors, I have come across
two very different types of motors, the wire wound
electro magnetic type( a whole bunch of manufacturers),
and the permenent magnet type (EWheel and
LEMCO).<br>In regards to use in an electric boat( or more
specifically in a sailboat, as an auxillary), what are the
pros and cons of each of these types?

My name is Marvin Motsenbocker, I live in
northern Virginia and like most of you, I am building
electric boats. Does anyone know of a Chinese person who
can read and write Chinese and who would be
interested in a joint project for electric boats in
Taiwan?<br>Marvin