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Old 17-12-2015, 16:59   #136
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Re: Tug of War - Electric vs Diesel

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I have the same motor & think the EP 2000 would be the way to go. $9,000 for the motor which is about the same price as a Beta. You'll need a charger & 6 12 volt batteries for the EP 2000. For the Beta you'd need a charger but fewer batteries for a house bank & separate starter battery. So up to this point the costs are pretty similar. If you are going to install or already have a generator for air conditioning, water making or whatever, then you are ahead of the game & I'd really consider electric. Under batteries alone Elco estimates a range of 6 hours at 60% of hull speed so for a boat with a 30' waterline length that would be 26.4 miles at 4.4 knots. However with just a 2.5KW generator running you would increase that to 539 miles at 5.5 knots. That would work for most people.
Elco Inboard Electric Motor EP-2000 | Elco Motor Yachts
That site recommends the EP-4000 which I imagine will be a lot more expensive than the $9k for the EP2000? IN fact it's $15000 without the engine mounts and no doubt other items.

I've sought a quote from the other company mentioned, I'll email this crowd as well and see what options come.

Do you know whether a 'gear box' is still require or is the motor run directly onto the prop shaft?

This is looking like it's just way to expensive at the moment.
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Old 18-12-2015, 06:49   #137
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Re: Tug of War - Electric vs Diesel

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That site recommends the EP-4000 which I imagine will be a lot more expensive than the $9k for the EP2000? IN fact it's $15000 without the engine mounts and no doubt other items.

I've sought a quote from the other company mentioned, I'll email this crowd as well and see what options come.

Do you know whether a 'gear box' is still require or is the motor run directly onto the prop shaft?

This is looking like it's just way to expensive at the moment.
Electric motors don't need transmissions. The Elco's come with everything you need except batteries. I think the EP4000 would be more than you need but that's up to you.
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Old 18-12-2015, 07:13   #138
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Re: Tug of War - Electric vs Diesel

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I think the EP4000 would be more than you need but that's up to you.
This brings up an interesting question. How much electric power (in kW or HP) does it take to replace a diesel without giving up any performance or capabilities?

First, the diesel loses several HP in driving water pumps, alternators, friction in the longer drive train, etc. Depending on whose data you use, size of the alternator and other variables could be typically 4-5 HP, certainly less that 10 except for unusual installations (engine mounted fridge compressor for example).

Then there is the big variable of the difference in the HP/torque curve of electric vs diesel where there seems to be no consensus at all.

Opinions I have read for electric to match diesel performance range from 40% of the diesel's rated power to about 75%.

In my case I have an engine rated at 58 HP and do not consider my boat overpowered I would shoot for the high end of the estimates so go for electric of 40-45 HP (30-35 kW) if I went electric.
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Old 18-12-2015, 07:54   #139
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Re: Tug of War - Electric vs Diesel

A lot of posts on this thread make it sound like you need to run a diesel at max hp for extended periods of time. It's been my experience that running a diesel wide open is extremely rare & I don't think diesels are designed for continuous duty at max hp anyway. We've all seen Jaws so it's pretty clear that running a diesel too hard for too long will lead to an untimely death of not only the diesel but the boat & crew as well.
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Old 18-12-2015, 11:43   #140
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Re: Tug of War - Electric vs Diesel

It's true, you don't normally run an ICE at full throttle for extended periods. But the fact is, we DO sometimes use full throttle, if only for short periods.


Doing a short sprint to cross a bar, or manoeuvring in strong wind etc. Having that extra power available can enhance safety.


So saying that since we usually only use half the available power means it would be viable to replace the engine with one half as powerful could leave you short in some circumstances.
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Old 18-12-2015, 12:20   #141
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Re: Tug of War - Electric vs Diesel

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It's true, you don't normally run an ICE at full throttle for extended periods. But the fact is, we DO sometimes use full throttle, if only for short periods.


Doing a short sprint to cross a bar, or manoeuvring in strong wind etc. Having that extra power available can enhance safety.


So saying that since we usually only use half the available power means it would be viable to replace the engine with one half as powerful could leave you short in some circumstances.
I was referring more to range & speed estimates. The implication has been that the range for electric power is inadequate because you can carry enough diesel to run at full power for extended periods & my point is that's not standard operating procedure.
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Old 18-12-2015, 12:43   #142
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Re: Tug of War - Electric vs Diesel

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Electric motors don't need transmissions. The Elco's come with everything you need except batteries. I think the EP4000 would be more than you need but that's up to you.
The thing is, I must go with what the manafactur recommends because if I underpower from their recommendations then I can't go complaining afterwards that it's underpowered. For my vessel the site clearly has my vessel in the EP4000 range and advises the comparative price. And the Elcos I've got to add mounts and a coupling.

It looks really nice, but the price is now approaching $18k. That 7 to 8 extra k is one hell of a lot of diesel.
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Old 18-12-2015, 12:44   #143
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Re: Tug of War - Electric vs Diesel

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I was referring more to range & speed estimates. The implication has been that the range for electric power is inadequate because you can carry enough diesel to run at full power for extended periods & my point is that's not standard operating procedure.




So at less than full power you'd be carrying enough diesel to go even longer. I'm not sure I'm seeing your point?
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Old 18-12-2015, 13:20   #144
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Re: Tug of War - Electric vs Diesel

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So at less than full power you'd be carrying enough diesel to go even longer. I'm not sure I'm seeing your point?
The issue is not diesel range, it's EP range.
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Old 18-12-2015, 15:32   #145
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Re: Tug of War - Electric vs Diesel

I would have thought the issue was EP range, weight, reliability and cost compared to ICE range, weight, reliability and cost.
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Old 18-12-2015, 16:30   #146
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Re: Tug of War - Electric vs Diesel

Weight would not be an issue for the typical monohull but I'm not sure about cats. More batteries but less fuel. In terms of reliability the motor has it's first scheduled service at 50,000 hours. That's pretty reliable. The cost is comparable if you're already getting a generator but if you're buying a generator just for the motors that's an extra expense. Of course there would be more benefits with the generator than just running the motors.
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Old 19-12-2015, 13:08   #147
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Re: Tug of War - Electric vs Diesel

Electric motors are massively reliable. But it's the reliability of the entire propulsion system that matters.
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Old 19-12-2015, 13:19   #148
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Re: Tug of War - Electric vs Diesel

Over the week I've been looking into this very seriously. Neither company has gotten back to me at all though.

No matter how I work it, doing the pricing 'without' a gen set, there is nothing comparative with price going electric. I'm looking at between and extra $3k to $8k depending on the replacement diesel. And of course I'd have to add a couple extra batteries and a gen set to make it even a possibility.

I might revisit it in ten years time but for now it's just not a realistic option. Which is pretty disappointing as we see the price of electric cars dropping, solar for domestic has dropped significantly. Why the hell are marine sets so expensive?
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Old 19-12-2015, 13:20   #149
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Re: Tug of War - Electric vs Diesel

Do you have any evidence, or have you heard, that the Elco systems are not reliable? I'd be surprised by that considering how long they've been in business.
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Old 19-12-2015, 14:27   #150
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Re: Tug of War - Electric vs Diesel

Rustic,

Are you considering only the initial costing? How much motoring are you expecting to do over the next 5 years, therefore fuel costs?


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