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17-12-2015, 16:59
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#136
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Registered User
Join Date: Jun 2011
Location: Tasmania, Australia
Boat: Bieroc 36 foot Ketch
Posts: 4,953
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Re: Tug of War - Electric vs Diesel
Quote:
Originally Posted by Scout 30
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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.
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18-12-2015, 06:49
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#137
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Registered User
Join Date: Oct 2014
Location: Florida
Boat: Scout 30
Posts: 3,112
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Re: Tug of War - Electric vs Diesel
Quote:
Originally Posted by Rustic Charm
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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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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18-12-2015, 07:13
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#138
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Senior Cruiser
Join Date: Oct 2007
Location: 29° 49.16’ N 82° 25.82’ W
Boat: Pearson 422
Posts: 16,306
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Re: Tug of War - Electric vs Diesel
Quote:
Originally Posted by Scout 30
I think the EP4000 would be more than you need but that's up to you.
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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.
__________________
The water is always bluer on the other side of the ocean.
Sometimes it's necessary to state the obvious for the benefit of the oblivious.
Rust is the poor man's Loctite.
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18-12-2015, 07:54
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#139
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Registered User
Join Date: Oct 2014
Location: Florida
Boat: Scout 30
Posts: 3,112
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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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18-12-2015, 11:43
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#140
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Registered User
Join Date: Sep 2006
Posts: 9,398
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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.
__________________
"You CANNOT be serious!"
John McEnroe
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18-12-2015, 12:20
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#141
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Registered User
Join Date: Oct 2014
Location: Florida
Boat: Scout 30
Posts: 3,112
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Re: Tug of War - Electric vs Diesel
Quote:
Originally Posted by 44'cruisingcat
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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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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18-12-2015, 12:43
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#142
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Registered User
Join Date: Jun 2011
Location: Tasmania, Australia
Boat: Bieroc 36 foot Ketch
Posts: 4,953
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Re: Tug of War - Electric vs Diesel
Quote:
Originally Posted by Scout 30
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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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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18-12-2015, 12:44
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#143
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Registered User
Join Date: Sep 2006
Posts: 9,398
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Re: Tug of War - Electric vs Diesel
Quote:
Originally Posted by Scout 30
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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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?
__________________
"You CANNOT be serious!"
John McEnroe
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18-12-2015, 13:20
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#144
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Registered User
Join Date: Oct 2014
Location: Florida
Boat: Scout 30
Posts: 3,112
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Re: Tug of War - Electric vs Diesel
Quote:
Originally Posted by 44'cruisingcat
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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The issue is not diesel range, it's EP range.
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18-12-2015, 15:32
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#145
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Registered User
Join Date: Sep 2006
Posts: 9,398
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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.
__________________
"You CANNOT be serious!"
John McEnroe
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18-12-2015, 16:30
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#146
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Registered User
Join Date: Oct 2014
Location: Florida
Boat: Scout 30
Posts: 3,112
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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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19-12-2015, 13:08
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#147
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Registered User
Join Date: Sep 2006
Posts: 9,398
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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.
__________________
"You CANNOT be serious!"
John McEnroe
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19-12-2015, 13:19
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#148
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Registered User
Join Date: Jun 2011
Location: Tasmania, Australia
Boat: Bieroc 36 foot Ketch
Posts: 4,953
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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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19-12-2015, 13:20
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#149
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Registered User
Join Date: Oct 2014
Location: Florida
Boat: Scout 30
Posts: 3,112
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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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19-12-2015, 14:27
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#150
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Registered User
Join Date: Jan 2014
Location: Coffs Harbour, NSW
Boat: FreeFlow 50 cat
Posts: 1,337
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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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