Hmmm
Maybe, leave the wife at home and add 4 more batteries.
ANYWAY, I can't speak to amps and wattage in the scenerio I had 10 years ago.
It was the day before my first day on a employee-type job in over 20 years. A Sunday
I had forgotten to put my main sheet up(Venture 25), when I stepped the mast and couldn't run the main.
So I went with my step-daughter and her friend on the proverbial 3-hour tour . . . jib alone.
We left about 3 pm.
For propulsion all I had was a 42 pound thrust MinnKota and a car battery that wasn't useable for the car any longer(weak . . . not dead). The battery hadn't been charged for over a week. Didn't much mater since I only used the motor for about 200 yards before sail went up and I had previously learned how to sail into the dock(no motor).
Got about 4 miles from dock and realized that the wind had shifted and I couldn't make headway back to dock. Close, but just not close enough. Try as I might, all I could get was a broad run and each run delivered further from dock . . . I was hoping a slight wind shift would aid my return.
ANYWAY, round about 8 pm . . . just before dark, I finally began returning under the MinnKota in calm calm conditions.
After about a couple of hours, I had to turn my navigation lights off to keep power to the motor, to keep it actually turning. I called my wife to let her know she might have to meet me near shore somewhere
I can only say, the motor was turning very much slower than normal and with the nav-lights on, much slower still.
I returned to the dock at a little after 11pm, with that motor moving me painfully slow, but moving me none-the-less at what I would consider a leisure walk.
So, even though I can't speak to wattage and/or amps, after all, a near-dead battery can only deliver so much, consider that running three small incandescent running lights would virtually stop the motor or make it so slow as to not be moving, the amperage being delivered had to be very minimal.
This is what I'd call limping home . . . really limping.
Now I know a Venture 25 doesn't compare to, even a Pearson 26, but that motor and old battery delivered me back to the dock.
If you really need to limp home, I'd rather find myself with a low-battery before finding myself out of gas and unlike the previous owner, I am not about to have 5 2 gallon gas cans, a couple of 1-gallons cans along with a 6 gallon gas-can lying around waiting to be needed for the obviously old(and probably dirty) gas they hold. BTW, how many boaters worry more about dirty gas, left-over gas, or even last-year's gas, because after all is said and done, they don't use their motors very much at all?
I intend to have a house bank(2 batteries) to run the cabin and light functions and all the lights are being changed to LED and I use a number of puck-lights. The house bank will also serve as my emergency back-up for my 24 volt motor. I think that moving at 1-2 knots(a speed at which I have actually enjoyed sailing . . kinda) will extend my range considerably, if I need it.
Gas, Diesel or electric . . . each can leave one stranded one way or another and all we can do is maintain our power-source the best we can and hope for the best.
The only real disadvantage to electric is that as boaters, we live in a petroleum society. Our mindset isn't geared to accept electricity for propulsion. I think this is the real problem with electric and why many boaters just can't quite trust electric.
When the day comes, when a larger percentage of boaters use electric . . . when your dock-mates are using electric . . . when we accept electric as a reliable source of propulsion, we'll all look back and wonder why we feared electric in the first place and why did we spend so much time on all the "what if" situations that would deem electric as an unreliable energy.
John Francis
Port Clinton
I think efficiency is important .It seems most efficient to run on the gen/charger with a full battery . The worst case would be to charge the batteries from the gen and then run off the batteries . since charging ( for lead acid ) is about 70% efficient . If you had a 60% charger you would get a dismal total of .60 times .70 = 40% overall efficiency!
A DC generator is the most efficient but it costs much more unfortunately.
Chris S
--- In electricboats@yahoogroups. , Ned Farinholt <nedfarinholt@com ...> wrote:
>
>
> The chargers range in efficiency from 60 to 85%. Most vendors do not spec publicly the input AC power required or efficiency. Delta Q is an exception though there is some ambiguity in their listing of current and rms current. The non-rms number may refer to the wave from a non-sinusoidal generator. The Honda EU units are advertised as pretty clean sinusoids. I have had some luck in contacting vendors directly in re input power.
>
> On a similar thread, what has been the experience of any who have used 48v chargers rather than 4 bank 12v chargers. Have you found a need to install balancers on series wired wet cell lead acid 6 volt batteries? I am hoping that routine checks with a voltmeter on each battery will find any bad batteries soon enough.
>
> BTW, my Torqeedo 801L base 24v 800w motor pushes my 2600 lb. Cape Dory Typhoon 18.5 ft waterline keel sailboat to 4 knots, 70% hull speed in calm conditions.
>
> Ned
>
>
>
> On Mar 4, 2010, at 1:46 PM, Rob Haynes wrote:
>
> >
> > By the number of posts on this subject this seems to be a popular and convenient way to extend your range. I'm wondering about efficiency. What are the losses going 110V AC to some other voltage thru a charger? Wouldn't a direct DC generator be alot more efficient?
> >
> >
> > ------ Original Message ------
> > Received: 08:20 PM PST, 03/03/2010
> > From: "Dave Hackett" <dave.hackett@...>
> > To: <electricboats@yahoogroups. >com
> > Subject: [Electric Boats] Battery charger limits and the Honda 2000 generator
> >
> >
> >
> >
> > I've seen some post on this group that they can run their Honda 2000 generator plugged into their shore power plug and use their battery charger to "limp" home. I'm wondering about the numbers.
> >
> >
> >
> > If I have a quad battery charger (eg Pro Charge) rated at 15 amps per battery (x4 = 48v), the full draw on the generator would only be (4 * 15A * 12V) = 720 watts. I just can't imagine getting even 2 knots at this power level. Am I missing something or do the chargers produce more then 15A when the draw out the other end is greater then 15A? Would this potentially burn out the battery charger?
> >
> >
> >
> > DaveH
> >
> >
> >
> > No virus found in this incoming message.
> > Checked by AVG - www.avg.com
> > Version: 9.0.733 / Virus Database: 271.1.1/2709 - Release Date: 03/01/10 03:34:00
> >
> >
> >
> >
> >
> >
> >
>
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