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Old 09-08-2021, 13:21   #346
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Re: Replace Diesel with electric engine

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Originally Posted by EngineerRetired View Post
So EVERY car manufacture on the planet making the switch has it all wrong? Hmmm, don't think so.



In ten to fifteen years when the price of diesel will be in the $10 a gallon range due to low production and carbon taxes everyone will be switching their boats to electric. Watch and see...
100% agreed!
In Finland more than 50% of the new cars are BEV (but there is also a lot of government funding). In Germany there's funding too, but much less.

Still, more hybrids and BEVs were registered than pure diesels. And honestly, what do you get for your ICE in 5 years when the BEVs become even cheaper, their batteries have 100kWh and more (i.e. a range of 500-700km) and can be charged 80% in 20 minutes?
I bought a BEV with 58kWh and two weeks ago I had to visit my parents, who live 340km away, twice within 5 days. What can I say - I was effectively only 15 minutes longer than before.
In Germany the last ICE will be produced in 2033-2035. That's only a bit more than 10 years!

This development does not stop for sailing vessels. Of course not pure electric unless the solar panels have 100% efficiency (which will never happen). But Hybrid will definitively be the new standard.
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Old 09-08-2021, 13:56   #347
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Re: Replace Diesel with electric engine

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Originally Posted by Adelie View Post
100hp is 75kW.

600nm at what speed and in what wind and sea conditions?
100 diesel hp ist without inner friction and without power for the oil & water pump, the generator, the belts, ...
Electric power is measured at the prop shaft.
Real life says 10 kW EP is nearly 20 hp diesel power designation. Let it be 60kW and it's fine.
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Old 09-08-2021, 15:17   #348
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Re: Replace Diesel with electric engine

Quote:
Originally Posted by Dirk01 View Post
100 diesel hp ist without inner friction and without power for the oil & water pump, the generator, the belts, ...
Electric power is measured at the prop shaft.
Real life says 10 kW EP is nearly 20 hp diesel power designation. Let it be 60kW and it's fine.
100hp is 74.6kW strictly speaking.

Effective power depends on where each is measured.
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Old 09-08-2021, 23:42   #349
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Re: Replace Diesel with electric engine

Comparing power output is difficult. Just take the alternator(s) on diesel engines… our setup could easily take 10hp just for spinning those, while an electric motor doesn’t have any of that. Then we have the pumps and transmission… soon you’re left with only half the rated hp.

Our member Steve D’Antonio wrote a nice article about it:

https://stevedmarineconsulting.com/h...er-and-torque/

also:

https://blog.greenyachtsales.com/blo...electric-motor
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Old 16-08-2021, 01:06   #350
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Re: Replace Diesel with electric engine

So I checked the power curve again and could tap the screen of my iPad to get actual values. At 6 knots we need 3.17kW, at 7.5kts 12.53kW and at 8kts 19.8kW.

As a 20hp outboard is 15kW, maximum speed should be 7.5kts or a little over.

I’m getting all enthusiastic for testing an outboard bracket on our swimming platform for testing this. I’m even thinking about adding a small electric drive… my 6kW diesel genset should even be able to get us through calms
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Old 16-08-2021, 03:06   #351
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Re: Replace Diesel with electric engine

So I checked the power curve again and could tap the screen of my iPad to get actual values. At 6 knots we need 3.17kW, at 7.5kts 12.53kW and at 8kts 19.8kW.

As a 20hp outboard is 15kW, maximum speed should be 7.5kts or a little over.


So I takt it as a fact:

My boat has 20 tons and a 85 hp diesel. 85 /4*3 = 63,75 Kw

But I don't need. Now my stomach thinking begins.
I only need... OK say half, thats 30 Kw
Whats about some security... 40 Kw

OK I can double up your values and yes you dont reach anything below 6 knots.
At 6 knots we need 3.17kW * 2 = 6,3 kW/h

Besides the fact of severe damage to nature we use LiFePo4 as we do not have another choice. Let us assume 210 Wh/kg

What we want is a chance to go 8 hrs with 6 knots + 2 hrs spare to reach then next marina and get current out of the plug (from elsewhere)

6,3 x 10 = 63 Kw in 10 hrs

say 200 Wh/kg is 5 kg per kW makes 5 x 63 = 315 + 20%(DoD) = 378.

says wikipedia. the truth is:

https://www.amazon.de/Electronicx-Ve...dp/B097H7FCWM/


1280Wh, 11,2 kg 705 € = 50 Batteries + 20% = 60 Batteries * 705€ = 42.300 € / 672 kg


Oh I forgot the generator. Yes I do have a 7,5 kW generator on board.
Running on saltwater. Joke - of course diesel. So f.. where is the discrepancy besides
spending another 25.000 to 70.000 USD for notting.

Really I DO NOT UNDERSTAND IT:
BUT the most annoying thing is.

What he have has its footprint.
When we throw it away we produce the next footprint.
When we buy a new thing we produce another footprint.
Whe we repair it or buy used things we minimise the footprint by 90%



We really should get rid of this supervised thinking and move to a better way of life.
Yes it is not good for those who want us to BUY, BUY, BUY, to maximise their profit on their 5000% mark-up.

Oh man, it is soooooo terrible stupid
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Old 16-08-2021, 05:20   #352
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Re: Replace Diesel with electric engine

moseriw,
I see you prepared well your post )
EP is not replace for diesel engine, I thought it was clear (may be not).
It is not for everyone.

Real example for last 5 years of stable work.
Boat: 2300 kg with 7 meters LWL
EP: 14 kWh battery and 3 kW electric motor, 400W PV
Got a range 55 nm at calm weather at 3,5 - 4 knots. Max speed a 6 knots at 3,5 kW. Each sunny day I get a +10 nm range from PV (using of electric kitchen reduce this value).

Battery got from two electric bus modules of 30V 240Ah each. Total 60V 240 Ah. It cost for me 1500 USD each, 3100 USD total with BMS.
Electric motor partially self-made: I rebuilded an acync motor in PMSM. Controller Kelly. Motor + controller + wiring = 900 USD
PV 400W with charge controller = 700 USD
220V outlet charge controller 1,5 kW = 100 USD
Invertor 60V -> 220V = 400 USD.

So, my EP total cost 5200 USD
It still have limited range comparing to diesel, but it work silently, I have a huge battery for home needs (220V, electric kitchen) and it slowly recharge from sun at anchor at middle of some bay. I don't need to take care of filters, oil, fuel waste at tanks. Maintenance of EP is very simple comparing to diesel.

For larger boats and without knowledge of an electrician, it will be much more expensive.
Thats why I wrote it is not for everyone. For large boats diesel is better choice.

s/v Jedi,
for your 20 meters boat with 25000 kg displacement you need a diesel. Keep in mind your hull have a own windage, so even in light wind you don't get calm weather values
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Old 16-08-2021, 06:26   #353
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Re: Replace Diesel with electric engine

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Originally Posted by zloitapok View Post
s/v Jedi,
for your 20 meters boat with 25000 kg displacement you need a diesel. Keep in mind your hull have a own windage, so even in light wind you don't get calm weather values
Yes, but in light wind I can sail or motorsail. We do 6 boat speed in 9kts wind. When I can maintain 6kts boat speed with 5hp, then a 20hp outboard should already work for 99% of everything. Powering off a lee shore is the kind of conditions where more power is needed, but I can do that under sail easily.

The big revelation for me is that my 6kW diesel genset is enough power to motor through calms at 6kts so I am independent from solar and batteries for long distance motoring.

Our typical motoring is entering and leaving anchorages as well as laziness for short rides like a 30 minute sail between two islands. I would want to do all of that without running a diesel and I think a 10kWh battery pack would allow this.
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Old 16-08-2021, 08:38   #354
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Re: Replace Diesel with electric engine

This is a cruisers forum and I thought we are discussing blue water themes or coastal cruising.

No doubt that an EP is essential on a lake where diesel/gasoline is prohibited.
I did it myself with an 26 ft boat and it was OK with an 350W motor driven for 2 hrs.
Not really a problem and it did cost me 300 € for the motor and the livetime of my cars battery.

So why discussing it?

No my problem are people who want to braeak any rules of nature by propelling at 6+ knots for 10 hrs with EP which is NONSENSE!

And the next stupid nonsense is to buy a genset für 15-20.000 USD to drive with EP when the diesel engine cost 12.000 including a new gearbox. (for the 300 NM's they use it during the season.)

And the next stupid nonsens is to replace an engine because it has uahh 3000 NM on it and it is sooo good to have it new.


My Ford Lehman is of 1981 and only God knows how many miles it did. But it does not suck oil and it does not smoke and yes I had to repair the starter and change all heat exchangers and...
it was no problem at all to do it and I bet it will do the next 40 years on 1800 rpm workload instead of the 3200 rpm of the new lightweight engines that give up within 5-6 years.

And it is soooo stupid to renew things just for the supervised good feeling.
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Old 16-08-2021, 09:30   #355
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Re: Replace Diesel with electric engine

I’ll repeat what I wrote somewhere else, if you a cruising it really makes very little sense to go electric.

Serial hybrids are inherently inefficient compared with a straight diesel for motive power so going serial hybrid in order to get range is irrational. You will burn about 20% more diesel once you exceed the battery range than you would just running straight diesels. To avoid this you could stay mostly within the battery range and only use the engine to get into and out of harbour. But if that is the case then you will only be using a tiny amount of diesel anyway with regular engines so there is little point going electric for environmental reasons - the emissions from this are so low compared to all the other emissions from sailing (embodied emissions of materials, supplies and so on for example).

If I use my diesel on average for an hour every week to get into and out of places, then my emissions will be around 10kg a week or around 500kg a year. I think I worked out somewhere that it would take 8 years of me running my engine to equal the embodied emissions in a lithium battery bank big enough for electric propulsion. And then keep in mind that diesel need not come from dino juice

There are other reasons to go all electric - almost zero maintenance, no diesel fumes, greater autonomy, etc - but you won’t be doing a big favor for the environment over a sailboat that uses its diesel engine frugally and you will be paying through the nose for these advantages. Going serial hybrid is the worst of both options as you have most of the costs of electric with all the maintenance and smells associated with diesel ICEs.
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Old 16-08-2021, 10:29   #356
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Re: Replace Diesel with electric engine

What he have has its footprint.
When we throw it away we produce the next footprint.
When we buy a new thing we produce another footprint.
When we repair it or buy used things we minimize the footprint by 90%
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Old 16-08-2021, 10:29   #357
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Re: Replace Diesel with electric engine

Quote:
Originally Posted by s/v Jedi View Post
Yes, but in light wind I can sail or motorsail. We do 6 boat speed in 9kts wind. When I can maintain 6kts boat speed with 5hp, then a 20hp outboard should already work for 99% of everything. Powering off a lee shore is the kind of conditions where more power is needed, but I can do that under sail easily.

The big revelation for me is that my 6kW diesel genset is enough power to motor through calms at 6kts so I am independent from solar and batteries for long distance motoring.

Our typical motoring is entering and leaving anchorages as well as laziness for short rides like a 30 minute sail between two islands. I would want to do all of that without running a diesel and I think a 10kWh battery pack would allow this.


My guess is that it is more like 10hp to make 6kt. I think Z’s graphs are under estimating power required at low speeds.
Push your boat using the dinghy at max throttle.
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Old 16-08-2021, 10:46   #358
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Re: Replace Diesel with electric engine

At 1/2 throttle a Yamaha 9.9 high thrust will push my 10 ton 36 foot waterline to 5 knots. I bet 10 hp through the right prop at the right speed will push Jedi's longer waterline to 6 knots.
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Old 16-08-2021, 10:58   #359
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Re: Replace Diesel with electric engine

Quote:
Originally Posted by zloitapok View Post
...

For larger boats and without knowledge of an electrician, it will be much more expensive.
Thats why I wrote it is not for everyone. For large boats diesel is better choice.

s/v Jedi,
for your 20 meters boat with 25000 kg displacement you need a diesel. Keep in mind your hull have a own windage, so even in light wind you don't get calm weather values
I don't see why EP would not work for Jedi. Bigger boat, so what, bigger motor and bigger battery. 6kt is 0.75SLR, ,most of the resistance is going to be skin friction, just a little wavemaking. If he drops to 3.5-4.0kt he's looking at 1.2-1.7kW. Just because he has a bigger boat does not mean he needs to motor faster than everybody else.
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Old 16-08-2021, 11:00   #360
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Re: Replace Diesel with electric engine

Quote:
Originally Posted by Na Mara View Post
I’ll repeat what I wrote somewhere else, if you a cruising it really makes very little sense to go electric.

Serial hybrids are inherently inefficient compared with a straight diesel for motive power so going serial hybrid in order to get range is irrational. You will burn about 20% more diesel once you exceed the battery range than you would just running straight diesels. To avoid this you could stay mostly within the battery range and only use the engine to get into and out of harbour. But if that is the case then you will only be using a tiny amount of diesel anyway with regular engines so there is little point going electric for environmental reasons - the emissions from this are so low compared to all the other emissions from sailing (embodied emissions of materials, supplies and so on for example).

If I use my diesel on average for an hour every week to get into and out of places, then my emissions will be around 10kg a week or around 500kg a year. I think I worked out somewhere that it would take 8 years of me running my engine to equal the embodied emissions in a lithium battery bank big enough for electric propulsion. And then keep in mind that diesel need not come from dino juice

There are other reasons to go all electric - almost zero maintenance, no diesel fumes, greater autonomy, etc - but you won’t be doing a big favor for the environment over a sailboat that uses its diesel engine frugally and you will be paying through the nose for these advantages. Going serial hybrid is the worst of both options as you have most of the costs of electric with all the maintenance and smells associated with diesel ICEs.
Jedi earlier indicated that when he current motor dies or fuel becomes too expensive, he's going to change to EP.
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