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Old 19-06-2017, 06:01   #31
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Re: Small generator + electric propulsion for dingy

What do you use the dinghy for?
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Old 19-06-2017, 06:06   #32
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Re: Small generator + electric propulsion for dingy

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I'm surprised that no one has mentioned the Torqeedo in this discussion. It is an electric outboard motor with equivalent thrust of about 3 HP. It is powered by its own self contained low voltage battery. The entire thing is lightweight and easily carried in one hand. The battery can be charged from any 12V source, like ship's power, for example. I've been using one to power my dinghy for 4+ years and I think it's just great.
Post #21 did.
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Old 19-06-2017, 07:18   #33
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Re: Small generator + electric propulsion for dingy

In addition to the breathing exhaust, the exhaust gas and pipe on a generator get hot- potentially burning you, the cargo in your dinghy or melting the inflated sections. Cannot recommend this idea
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Old 19-06-2017, 07:19   #34
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Re: Small generator + electric propulsion for dingy

You've gotten a lot of good advice.

EITHER electric (Torqueedo etc.) OR gas (2hp outboard) makes sense, but certainly NOT both.

Your hybrid system will be heavier than either, more expensive than either, less powerful than gas, less endurance than gas, will create dangerous exhaust situation, and will be vulnerable to destruction of the generator in case you ship a wave -- which commonly happens to dinghies.

Electric is great -- silent and clean. Not much power or range, but enough for many cruisers. Recharge on the big boat with solar or whatever. A great option for many.

OR

A small gas outboard -- ideally a 2hp two stroke. Light, powerful (compared to electric), very long endurance -- small gas tank will give you 10x or more the range of one charge on the electric. Won't be ruined by salt water if you ship a wave; exhaust handled safely. Cheap as chips if you buy a used one.

Take your pick; both are good options, each in its own way. But electric motor plus generator is the worst of both worlds, in fact worse than either in many respects.
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Old 19-06-2017, 14:20   #35
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Re: Small generator + electric propulsion for dingy

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Good old magic EP again. Somehow, according to Torquedo, 480W output power (0.64HP) = 3HP.
[/I]
Their claims are always unrealistic, but this is ridiculous!

I keep asking, but the EP guys never answer: if an electric motor is equivalent to a petrol or diesel engine several times bigger, why don't they use an electric motor to power the generator?

In this instance: they claim 480 watts electric = 3 HP petrol.

A 3 HP petrol motor would nicely power a 1600 watt generator.

So use a 500 watt electric motor instead, and run it off the generator, and there'd be 1100 watts surplus to use for propulsion!

And 1100 watts electric would be equal to about 20 HP wouldn't it?

Free power and perpetual motion!

Why haven't the EP guys thought of this?
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Old 19-06-2017, 15:16   #36
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Re: Small generator + electric propulsion for dingy

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Their claims are always unrealistic, but this is ridiculous!

Free power and perpetual motion!

Why haven't the EP guys thought of this?
How about installing LED lights over your solar panels so you can recharge your batteries at night from your solar panels? Perfect, 24hr power from solar panels!
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Old 19-06-2017, 15:21   #37
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Re: Small generator + electric propulsion for dingy

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How about installing LED lights over your solar panels so you can recharge your batteries at night from your solar panels? Perfect, 24hr power from solar panels!
:thumb Great idea!
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Old 19-06-2017, 15:36   #38
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Re: Small generator + electric propulsion for dingy

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Originally Posted by 44'cruisingcat View Post
Their claims are always unrealistic, but this is ridiculous!

I keep asking, but the EP guys never answer: if an electric motor is equivalent to a petrol or diesel engine several times bigger, why don't they use an electric motor to power the generator?

In this instance: they claim 480 watts electric = 3 HP petrol.

A 3 HP petrol motor would nicely power a 1600 watt generator.

So use a 500 watt electric motor instead, and run it off the generator, and there'd be 1100 watts surplus to use for propulsion!

And 1100 watts electric would be equal to about 20 HP wouldn't it?

Free power and perpetual motion!

Why haven't the EP guys thought of this?
It's not quite that good. Torquedo figures say that you require 1000W (1.34 HP) of input to their motor to get that 480W of output (shaft) power. So you only get 1/2 as much "free energy"
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Old 19-06-2017, 17:40   #39
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Re: Small generator + electric propulsion for dingy

I have the Torquedo 1003. Love it. Can push the dinghy at 4+ knots for a half an hour. Haven't actually tried that but seems about right. Light and easy to hit in and out of dinghy just by hand. My last two, 4 day trips using the dinghy daily for short trips didn't event need to recharge. Well worth the money IMHO.
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Old 19-06-2017, 17:55   #40
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Re: Small generator + electric propulsion for dingy

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I have the Torquedo 1003. Love it. Can push the dinghy at 4+ knots for a half an hour. Haven't actually tried that but seems about right. Light and easy to hit in and out of dinghy just by hand. My last two, 4 day trips using the dinghy daily for short trips didn't event need to recharge. Well worth the money IMHO.
So a range of about a mile, return.

How much do they cost?
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Old 19-06-2017, 18:11   #41
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Re: Small generator + electric propulsion for dingy

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So a range of about a mile, return.



How much do they cost?


They say 2.8 miles @ 5 knots. At 2 knots, 20 miles. I would need to do some more testing to see if that really plays out, but seems pretty close so far.

http://www.torqeedo.com/us/en-us/pro...M-1142-20.html

$1600 US from defender.com (You can get a bigger battery too)
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Old 19-06-2017, 18:30   #42
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Re: Small generator + electric propulsion for dingy

Here honda 2 hp outboard.
https://wenatchee.craigslist.org/boa/6134687081.html
Then almost a thousand saved to buy fuel for it
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Old 19-06-2017, 18:36   #43
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Re: Small generator + electric propulsion for dingy

Ah hahaha.

Tell me you meant to post this on April 1, your computer went into sleep mode, and it just woke up?
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Old 19-06-2017, 19:29   #44
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Re: Small generator + electric propulsion for dingy

It is actually quite common to power a 12, 24, or 36V trolling motor with a generator. Power Max in FL makes converters just for this purpose. I have several of their products, and am quite satisfied......although I don't really see the benefit for you in this situation. It seems that by the time you add the battery, generator, converter and troller, the dingy would be crowded? We run all Honda EU2000 inverter generators on the boats with several thousand trouble free hours of operation. Quiet and easy on gas as well.
Something else to consider is that trolling motors are not designed for constant full throttle use. With an endless power supply, it's very easy to burn them up. (From experience)
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Old 19-06-2017, 20:19   #45
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Re: Small generator + electric propulsion for dingy

I have an 8' Livingston I use as a utility boat around the home dock. I have a 2hp Merc I used, but no longer running as usual. I got the smallest Minn Kota and can do maybe 3kts. The battery is connected to a solar cell when not in use. The whole setup was much less than a trip to the outboard shop.
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