Ok, try this again...

This is for a small day sailor - nor a rubber raft.

The previous message was...

The outboards on small day sailers seldom have alternators, which means
no way to charge batteries.
Best of the best seems to be the air cooled 5hp Hondas - but no electrics.

I've wondered about powering an electric motor directly from a small generator?
I saw a Honda that makes both 12vdc and 120vac - but (at the store) couldn't
find any info on actually usable output currents.

Retail is often so frustrating...
Outboards are rated in horsepower. No thrust rating?
Trolling motors are rated in pounds thrust. No power rating?

I'm thinking a 60-100 pound thrust motor on a 1500 pound displacement hull
isn't going to win any drag races, but should (eventually?) move out.

The limiting factor is battery charge (as noted this thread).

But with a gasoline powered "battery"?

Somebody want to knock some sense into this idea?


Richard


The one response made good sense.
Convert everything to watts.
I can do the electric part easy.
But I'm not sure how to convert gas power to watts?
Or, as he also pointed out, how closely they will correlate?

For a full discussion on electric boats, try a Google search - There is a
ton of info out there!

Here is one site with many links:

http://www.econogics.com/ev/evboats.htm

As a guide - A Minekota 2HP outboard drive requires a maximum of 40A at 48V.
Presumably the 48V is obtained by using 4 12V or 8 6V batteries - about
400AH of storage. But, you should not discharge the batteries below about
50%, so really you have about 200AH to work with. This would give you about
5 hrs with a 2HP motor.

The 6V golf cart batteries will stand up better to the heavy duty charging
cycle but will probably fail after about 5 or 6 seasons. These batteries
would weigh about 500lb - about same as another 3 people on board. 12V deep
cycles would probably weigh about 1/2 as much but perhaps not last as long.

Regarding a portable charger - I believe (from memory) that a 2KW Honda
would put out about 8A of 12V DC, so that won't really cut it. It will also
put out about 1600 watts of 110V A/C which could be used to power an
on-board charger - Still wouldn't replace the total draw, but would give
longer run time. Possibly, y0u could install a 110V motor on an old outboard
drive! (1HP = 746W).

No easy answer! A fuel cell would be best because of much higher conversion
of fuel energy to electric power, but these are not yet readily available.

For most efficient solar power, try installing a mast and some sails

GBM


"cavelamb" wrote in message
ink.net...
Ok, try this again...

This is for a small day sailor - nor a rubber raft.

The previous message was...

The outboards on small day sailers seldom have alternators, which means
no way to charge batteries.
Best of the best seems to be the air cooled 5hp Hondas - but no electrics.

I've wondered about powering an electric motor directly from a small
generator?
I saw a Honda that makes both 12vdc and 120vac - but (at the store)
couldn't
find any info on actually usable output currents.

Retail is often so frustrating...
Outboards are rated in horsepower. No thrust rating?
Trolling motors are rated in pounds thrust. No power rating?

I'm thinking a 60-100 pound thrust motor on a 1500 pound displacement hull
isn't going to win any drag races, but should (eventually?) move out.

The limiting factor is battery charge (as noted this thread).

But with a gasoline powered "battery"?

Somebody want to knock some sense into this idea?


Richard


The one response made good sense.
Convert everything to watts.
I can do the electric part easy.
But I'm not sure how to convert gas power to watts?
Or, as he also pointed out, how closely they will correlate?

I stopped by Northern Hydraulic today and picked up a catalog.

Lots-o gen sets from backpack to ship/shore power.

Pretty much priced accordingly too.

A couple of higher end units could make 20 amps of 12 vdc.
But that's only 240 watts - a SMALL trolling motor?
And several kilo-bucks required to do it?

I think this idea goes back to the drawing board.


Sats

Very cool idea, please let us know what you come up with.
MMC
"cavelamb" wrote in message
ink.net...
I stopped by Northern Hydraulic today and picked up a catalog.

Lots-o gen sets from backpack to ship/shore power.

Pretty much priced accordingly too.

A couple of higher end units could make 20 amps of 12 vdc.
But that's only 240 watts - a SMALL trolling motor?
And several kilo-bucks required to do it?

I think this idea goes back to the drawing board.


Sats

MMC wrote:

Very cool idea, please let us know what you come up with.
MMC
"cavelamb" wrote in message
ink.net...

I stopped by Northern Hydraulic today and picked up a catalog.

Lots-o gen sets from backpack to ship/shore power.

Pretty much priced accordingly too.

A couple of higher end units could make 20 amps of 12 vdc.
But that's only 240 watts - a SMALL trolling motor?
And several kilo-bucks required to do it?

I think this idea goes back to the drawing board.


Sats





40 amps 12VDC to drive a moderate trolling motor will run
over $3000 - off the shelf gen set.

It's going to be a pretty big package too.

FWIW...

As with hybrid autos, generator / battery / electric drive rigs have
advantages and disadvantages.

One hp = 750 watts, about.

a 5 hp generator produces about 3750 watts of electricity steady state,
a little more for a second or two startup, whatever the voltage /
current output might be.

An electric motor might be able to provide more horsepower than that
for a short while, using batteries as "nitro" for your boat, while
otherwise smoothing the power available or even recharging at a dock.

Small batteries will provide short bursts of "overdrive" for a short
period, larger ones proportionately.

The weight you might save in batteries could be compensated for by a
better generator.

If you can cruise at about 4 hp, you will be able to use a kilowatt for
amenities, topping up depleted batteries, etc.

If you can sail and use the prop to charge batteries, you may have the
best of all worlds.

If you don't mind pottering along at about half or 3/4 of calculated
hull speed, you can do it on surprisingly little power, if you are not
bucking a strong wind, and if you can use tides and currents to your
advantage, may get where you want so long as time is not of the
essense.

There is a lot to think about, here. There will be some
transformational loss, ie torque to electricity, battery charge /
discharge losses, and electrical to torque efficiency.

Motor / generator combined devices are becoming more practical and
efficient all the time. Quebec Hydro holds patents for a wheel motor /
generator, and has offered info for developers, but strangely, will not
respond to me, perhaps if GM or Ford were to call in francias?

CTC offers a Chinese wheel motor / generator brake battery assisted
bicyle for under a grand, it's about 1/2 horsepower.

We are on the cusp of many new things, soon. The attitude display
promises to be interesting.

Terry K

Terry K wrote:
As with hybrid autos, generator / battery / electric drive rigs have
advantages and disadvantages.

One hp = 750 watts, about.

a 5 hp generator produces about 3750 watts of electricity steady state,
a little more for a second or two startup, whatever the voltage /
current output might be.

An electric motor might be able to provide more horsepower than that
for a short while, using batteries as "nitro" for your boat, while
otherwise smoothing the power available or even recharging at a dock.

Small batteries will provide short bursts of "overdrive" for a short
period, larger ones proportionately.

The weight you might save in batteries could be compensated for by a
better generator.

If you can cruise at about 4 hp, you will be able to use a kilowatt for
amenities, topping up depleted batteries, etc.

If you can sail and use the prop to charge batteries, you may have the
best of all worlds.

If you don't mind pottering along at about half or 3/4 of calculated
hull speed, you can do it on surprisingly little power, if you are not
bucking a strong wind, and if you can use tides and currents to your
advantage, may get where you want so long as time is not of the
essense.

There is a lot to think about, here. There will be some
transformational loss, ie torque to electricity, battery charge /
discharge losses, and electrical to torque efficiency.

Motor / generator combined devices are becoming more practical and
efficient all the time. Quebec Hydro holds patents for a wheel motor /
generator, and has offered info for developers, but strangely, will not
respond to me, perhaps if GM or Ford were to call in francias?

CTC offers a Chinese wheel motor / generator brake battery assisted
bicyle for under a grand, it's about 1/2 horsepower.

We are on the cusp of many new things, soon. The attitude display
promises to be interesting.

Terry K


Hey Terry,

Does your crystal ball show any AC 110 VAC powered trolling motors
on the horizon?

The littlest Honda EU series generators make 1kw, 2kw or 3kw depending
on model. $699,999,1788
And two can be buddied up with a parallel kit for 30 amps.

There is also a 2500 watt Honda "tube frame" set listed for $629.

But all this is 110VAC!
So we have to include an appropriately sized battery charger for
each trolling motor. 70 to 100 amp chargers for $60 - $70? each.
Should be able to hold 12-15 amps continuous.

May work after all?

But sure would work a lot mo better if we had AC motors...

$.02

Richard

"cavelamb" wrote
The littlest Honda EU series generators make 1kw, 2kw or 3kw depending
on model. $699,999,1788
And two can be buddied up with a parallel kit for 30 amps.

There is also a 2500 watt Honda "tube frame" set listed for $629.

But all this is 110VAC!

Those generators have built in chargers. The 2kw unit has an 8 amp DC
battery charging output. SEE:
http://www.mayberrys.com/honda/gener...ls/eu2000i.htm

With a high quality charger, you might get a bit more by using the A/C - But
these chargers are much more expensive.

So, lets say you use two generators putting out 16 A - These can replenish
16 AH for each hour they are run. You could start with 400Ah of battery
capacity fully charged and plan on running this down to 200AH - If you do
this over, say, 8 hours while running the generators, you would get
25+16=41A to operate the electric outboard. Not bad if you can then get back
to shore power. Alternatively, if you can carry enough fuel, you recharge
overnight using the generators which now need to run 24 hrs/day!

BTW -110V A/C could be dangerous on a boat!

110vac 60Hz outboards? Not really. For electric motors to provide
variable speed and torque, variable frequency and voltage ac drive,
switched dc really, is required.

What I see ahead is chopper controlled 48 vdc electric moter /
generators, getting better and better so fast it'll be hard to keep up.
We will see them in road vehicles, such as the electric bicycle
previously mentioned, for modest requirements, and soon, modest town
commuter cars. The vehicle will be propelled by wheel motor / brake
units, with no transmission, motors in wheels and a small optimised
engine or plug in at home to recharge when idle, or drive slowly and
economically even with a low battery.

Driving economically in a low wind resistance lightweight land vehicle
can be economical. Economy has gotta make a comeback.

I want an eco-micro (TM) or eco-mini (TM).

Of course, this is my projection for what I want. Higher voltages get
more and more dangerous in wet conditions, even if higher frequencies
and higher voltages do promise high power and light weight.

See the eliica electric car for a vision of the future. These motor
generators can be made at home with a brake rotor, backing plate, wire
coils, and super magnets glued to the rotors. The switching controllers
are a different matter. The motors were first developed as wind
generators.

Batteries are where it's really gonna hit the fan. Fast charge lithium
ion cells are the best around, but who knows what will turn up next.
Meanwhile, what do we do with dead lead-acid, nicads, etc. chuck 'em in
the dump? I can't find a way to recycle carbon-zinc, or alkalines
around here.

Whatever happened to aluminium / lye cells, with replaceable aluminium
"fuel" and recyclable / rechargeable carbide crystals "exhaust?"

Whatever happened to fusion power?

A small trolling motor can be run from a small generator, using only a
small battery to smooth things out. A balance between electric motor
power / recharge capability, battery capacity / weight, range, and
generator requirements will serve different recipies for daysailors,
voyageurs, racers, campers, cruisers, whatever. Those who want to run
bass to death will always want more power than any battery that we can
see today could provide.

Why no pto on these little gennies? A prop could sit at the end of a
rooster tail rig, just for efficiency and long range, at idle. Every
genny should have a pto. Why are not all air conditioners switchable
to heat pump mode? (Flip the control panel around?) Think of the
national savings in energy if all a/c could provide cheap heat.

Prudence ignored.

As far as I am concerned, being on the boat is where it's at, and where
the boat gets to is secondary.

That's why I am a cruiser, sailing nowhere special at economical speed.

It's relaxing.

Terry K

In article .com,
Terry K wrote:

110vac 60Hz outboards? Not really. For electric motors to provide
variable speed and torque, variable frequency and voltage ac drive,
switched dc really, is required.

Yes? Someone should have told the machine tool people, who are fitting
variable freq drives all over the place.

You're right, tho - those are 3 phase motors fed thru a VFD that takes
single phase input & synthesises 3 phase out. But then you can control
speed quite simply.

Building an o/b I leave to someone else. Personally I fail to see the
point except for a very narrow use base. Turning liquid fuel into
mechanical energy directly seems a lot simpler. I'll keep using my
little Honda 4 stroke o/b.

PDW