Electrical Propulsion vs Diesel Propulsion

[Sailmonkey]

Originally Posted by Therapy

If you dig into them you will find that they did not perform as advertised. Not by a long shot. Lots of talk, no action.

interesting......I will commence digging

[jostalli]

Originally Posted by Therapy

There is one on this forum. Can't remember name.

Search back for thread/s on L420

http://www.cruisersforum.com/forums/...fans-5250.html

Yes I have read that thread in full as the Lagoon 420 is on top of my short list of next boats. Even the biggest supporters of the hybrid have now converted. I found out by checking their individual blogs.

[Therapy]

Originally Posted by jostalli

Yes I have read that thread in full as the Lagoon 420 is on top of my short list of next boats. Even the biggest supporters of the hybrid have now converted. I found out by checking their individual blogs.

But from what I have read they are quite the minority.

[Therapy]

Originally Posted by Sailmonkey

interesting......I will commence digging

Cruisers & Sailing Forums - African Cats

Lots of the fastcat threads were heavily moderated with many posts deleted for some reason or another.

[Sand crab]

Sailmonkey, The (Poon) Tang debacle is covered in the other forum. The fancy electronics set the boat on fire but the crew managed to put it out. The entire boat was *****.

[Alberto]

Originally Posted by Sovereigndreams

There are some great points in this thread in regards to conversion. Thank you for the input regarding the thru hulls and removal of the fuel tanks. I need to remember an electric propulsion system is based on various components and I am beginning to think it would be overkill to immediately eliminate the thru hulls and fuel tanks. I'm going to build my own system based on a 72 volt mars motor. Alberto, can you describe how you are charging your batteries in this system. I was looking for 72 volt charge controllers and thinking I would need to run solar and or wind in series to achieve 72 volt charging, but you stated you are charging each battery independently, is that correct?

As you are building your own system, allow me to describe mine:

Brushed MARS (ETEK RS) motor, very flexible, as it is suitable for 24V, 36V, 48V and 72V systems, the higher the voltage, the higher the power and RPMs. Although systems above 48V are considered high-voltage, I decided on 72V to be able to cruise at between 3 and 4 knots drawing 10 Amps or less (calm conditions) to minimize Peukert effect (whose Law states: “as the rate of discharge increases, the available capacity decreases”). With a bottom badly needing attention I get 3.6 knots drawing 10 Amps in flat water.

Kelly PM72401B controller, which I really like. It allows all sorts of programming by the user through a serial interface to a laptop. The company provides excellent customer support; they revised my design over and over, I would send them inquires and diagrams in the evening and next morning I would have their response. The controller is mounted on a beefy aluminum heat-sink (it has little heat to dissipate as I normally run the system at low amperage).

Aluminum frame made of 4” angle, ¼” thick. Houses the motor, transmission gear and bearing, and acts as a heat sink. The design provides structural integrity on three axes and allows for multiple reduction configurations using the same belt (the initial 2.4:1 ratio was fine). The bearing is self-aligning and sealed, so no maintenance required. Transmission is synchronous gear, 30mm belt.

Six AGM Group 31 batteries (West Marine, manufactured by East Penn, they are available under different brands).

QuickCharge MB1210x6 charger. It charges each battery independently according to the selected charge profile (seven available). Charging batteries independently is very important as the most negative ones are subject to higher loads, and in time you'll notice they start taking a little longer to complete the cycle (for this season I will be switching batteries 1 and 6 to compensate wear). Charging time for a fully depleted bank (i.e. 40%) could take up to 10 hs. For getting in and out of the marina, they go into absorption immediately.

Additional components: heavy duty solenoid (capable of 400 Amp peak), potentiometer, Anderson heavy-duty quick-disconnect, heavy-duty fuses, wiring, amp- and volt-meter, a custom made instrument panel in the cockpit (voltmeter, key, LED indicators), wiring, etc.

I adapted the diesel throttle control, it now connects to the potentiometer and to a micro-switch to select fwd/rev.

The engine room houses everything except the battery charger, and also serves as a new, large storage compartment given the smaller size of the system (more storage where the fuel tank was located, and where I installed the battery charger).

As part of the system I bought a multi-battery intelligent monitor that I could never calibrate. The unit was sent to the manufacturer for checking (it was fine), who provided some help with different configurations, none of which worked, and in the end I returned it.

Propeller: I still have the 2-blade 13x10 inherited from the diesel. It works perfectly fine with the system, but I am tempted to replace it with a 13x14 3-blade to take full advantage of the flat torque response. I think that I’ll do it when hauling out for bottom painting in May.

Hope this helps. I strongly recommend the Electric Boats Yahoo Group (electricboats : Electric Boats) to anyone interested in EP, it has comprehensive information, and very knowledgeable members always willing to help.

Alberto

[deckofficer]

Alberto,

Good write up. I also use an Etek in a project, a lot of power in a 26 lb package. I don't know many cruisers that even know about the Peukert effect. And running at 10 amps @ 72 volts for 3 to 4 kts, that is sweet, since the motor is capable of 100 amps cont, and 400 amps for a thermal restricted time frame.

[JRM]

Originally Posted by jostalli

Wait, did you not read my last post? Almost all of the hybrid Lagoon 420's have been converted to conventional diesel by the owners. I am asking for someone to find me a hybrid Lagoon 420 owner who is happy with the hybrid.

I haven't read to the end, so I apologize if his has been answered already. There's a guy named Steve on the Yahoo electric boats list who loves his Lagoon. He's reworked it as the original installs were horrible. Also, most of the people who convert back (both of the articles I read :-) were sold a bill of goods on regen. Regen really doesn't work practically. Maybe enough for house, but not practical for traction bank.

It's a bit disingenuous to claim that all hybrid electric is bad because one early commercial attempt failed. Not all cars are failures because [redacted] burns through ignition coils. It's a bad design.

JRM

[jostalli]

Steve is happy because he has a custom hybrid system which most likely would not be supported by Lagoon. Also, it's no longer an "early commercial attempt" as Lagoon is selling brand new boats with their hybrid system. Even those with the latest "version" of the Lagoon hybrid on their 420's still converted to diesel. I too read that most owners were not pleased with the regen performance but I don't think that was the only reason they converted to diesel.

Lagoon's hybrid is flawed in my opinion but at this point it is the longest running commercially available hybrid package we have to test and so far it has failed.

I am not bashing hybrid I am just frustrated that there aren't many options for someone who really wants a hybrid blue water boat for all the benefits already mentioned.

[niel12]

I want to thank all for their contributions. I have learned far more that i knew before.

When i planned my hybrid system i planned it arround two extremes. One being headon wind with high waves as opposed to flat seas with no winds. With that in mind i assessed what i had and what i needed to make this hybrid thing work.

I have two battery banks of 800 A/H each a wind Gen and two Solar panals. Research indicated that i would need a huge battery bank to store enough energy for two 3Kw electric motors to work off the batteries. I thought of numerous ideas of back charching etc. Another issue was the 10 Kv genset and and all it's pro's and con's. Then i realised to generate elctricity without fossil fuel will remain a dream so i updated my planning and decided on the following:-

1. Install two 24Volt x 2Kw electric motors.
2. Install two 5Kw Gensets with 24 Volt/ 12Volt batery chargers

I run the electric motors off the one Genset which burn 1.9L Diesel per hour. Running one electric motor at 1400 rpm at 3knots will give me a range of in access of 900 sea miles on my existing fuel capacity.

While the Genset is running one Kw is directed to the batery banks with a 12V batery charger.

The second Genset is wired and linked up as the first a serves as a backup which at $1000 is not too much in view of the configuration.

This in a nutshel is my plan for electric propulsion.

[Dockhead]

Originally Posted by osirissail

Electric propulsion has been beat to death on this and other forums for years. And it all boils down to:
1. Electric propulsion works great - heck, all the major giant cruise ships use electric propulsion.
2. Batteries to store and power the electric motors on yachts/sailboats are not adequate to the job now. Maybe in the future they will be, but not quite there yet.

So you would have to - just like the giant cruise ships - run diesel engine generators to power the electric propulsion unless your needs are for less than an hour to two or so per day between charging. Little boats use the little electric trolling motors quite effectively.

Lots of companies and folks are working on the idea and sooner or later it will become practical, but not quite yet. The current systems are very expensive compared to old fashioned diesel engine propulsion. - The electric systems require some exotic batteries and control equipment which are not now very economical in comparison.

I think all of this is exactly right.

However, it is not an argument against all electric propulsion. It is just an argument against electric propulsion which requires battery storage of the energy required.

It seems to me that existing technology is perfectly adequate for an excellent diesel-electric propulsion system which would offer considerable benefits compared to a conventional propulsion system.

Let's take my boat:

I have a 100 horsepower Yanmar main diesel propulsion engine PLUS a heavy 1000cc three-cylinder diesel genset engine. That's a lot of machinery on board.

Propulsion duty rarely requires 100 horsepower, or even 70 horsepower. I think even a fast cruise in moderate seas is only using about 30 horsepower.

So what if we replaced the two diesels with a single 50 or 60 horsepower diesel engine driving a big generator, and a larger (but not enormous) LifePO battery bank.

Propulsion would be by an electrical drive pod which swivels in all directions and which can generate power while sailing.

If I need to motor 100 miles across the English Channel (as I did last summer in a flat calm), I just put on the genset, use 20 or 30 horsepower for propulsion and enjoy abundant electrical power for other uses.

If I get into a storm and need 100 horsepower to punch through vicious seas, I've got them -- genset at full output plus batteries. I cannot use 100 horsepower for long, but should be enough for critical situations.

If I want to go into or out of harbor on a good sailing day, I don't necessarily have to fire up the generator -- can do it silently.

The swivelling pod gives me Beneteau-Sense style maneuvering at the dock.

I can generate totally free power in any wind which gives me hull speed.

I have quite a bit less machinery on board, and the one diesel engine which remains will be used MUCH more efficiently -- near its ideal load nearly all the time.

There is no big hole in the hull with a spinning shaft in it, no stuffing boxes with attendant sinking risks.

I would think that it might not even be really more expensive, or not much more expensive, compared to conventional with a much bigger main propulsion engine plus big genset.

What's not to like? Since large ships use exactly the same system it's not as if we are dealing with speculative technology. I think the only missing link is a high quality mass produced electrical propulsion pod in the size ranges needed for our boats.

As someone pointed out, there is some loss of efficiency due to two conversions from mechanical to electric back to mechanical. But surely this is more than compensated for with other efficiencies:

1. Smaller and cheaper diesel engine used much closer to its maximum efficiency, and in a regime which gives much better longevity.

2. Less weight of machinery.

3. No mechanical losses in gearbox, stuffing box, cutlass bearing.

4. Single system providing both electrical power and propulsion, instead of two separate systems.

It seems to me that this must surely be superior in almost every way to a conventional system.

[deckofficer]

All your points are valid and pretty much mirror my train of thought. On a cat with twin electric drives, you get precise handling in tight spots because of the low rpm torque of an electric motor coupled to large diameter and pitched props. Your concept of only needing max power for short duration is spot on, and that is the beauty of an electric, most will give 4 to 5 times cont power for a thermal limited time frame. An added feature is the motor has the same high efficiency throughout its power range, whereas a diesel is only efficient (if you can call it that) at 3/4's throttle and at the torque peak rpm. When using a DC gen set, you save a lot of weight over a conventional 120/240 VAC 60 cycle generator, at the 20Kw level, better than a 200+ lb savings and you have the flexibility of placing this weight where it is a low and balanced load in your hull. You just run your inverter off the propulsion bank and the output of the diesel DC gen set is the DC charging voltage for the bank. I will be using a 48 volt bank because you still have choices for a good price on mass produced inverters that run on that voltage. And when you kick on that 1200 watt galley appliance, instead of pulling 100 amps on the DC side at 12 volts, your pulling 25 amps at 48 volts.

[Dockhead]

Originally Posted by deckofficer

All your points are valid and pretty much mirror my train of thought. On a cat with twin electric drives, you get precise handling in tight spots because of the low rpm torque of an electric motor coupled to large diameter and pitched props. Your concept of only needing max power for short duration is spot on, and that is the beauty of an electric, most will give 4 to 5 times cont power for a thermal limited time frame. An added feature is the motor has the same high efficiency throughout its power range, whereas a diesel is only efficient (if you can call it that) at 3/4's throttle and at the torque peak rpm. When using a DC gen set, you save a lot of weight over a conventional 120/240 VAC 60 cycle generator, at the 20Kw level, better than a 200+ lb savings and you have the flexibility of placing this weight where it is a low and balanced load in your hull. You just run your inverter off the propulsion bank and the output of the diesel DC gen set is the DC charging voltage for the bank. I will be using a 48 volt bank because you still have choices for a good price on mass produced inverters that run on that voltage. And when you kick on that 1200 watt galley appliance, instead of pulling 100 amps on the DC side at 12 volts, your pulling 25 amps at 48 volts.

Yes, the principle is called "peak shaving" in the power industry, IIRC.

Instead of sizing the power plant to the short-term peak loads (like on my boat with a 100hp Yanmar), you can size it to efficiently support the normal loads, and use a different source of power to handle the short-term peaks. It adds enormous efficiency.

I am using the same principle with terrific results with my Victron charger/inverter. My genset produces 6.5kW at full output. My shore power connection is limited to 16 amps so about 3.6kW. Victron can add 3kW, and in fact 6kW for a short period of time to that. This means that I can drive loads on board which need 12kW for short periods of time, such as electric motor starting inrush loads. So I can use a 2.5kW electric kettle or my 2.2kW microwave, or even both, while on shore power and using power for other needs. I can fully air condition my boat if I ever go to the tropics, and I won't have to upgrade the genset (and use the upgraded genset in a very inefficient regime).

Yes, Victron sells mass-produced inverter/chargers in 48v, and I'm sure others do as well. The "power boost" function, which draws power from batteries to supplement genset power when needed, is superb.

[smj]

Originally Posted by deckofficer

All your points are valid and pretty much mirror my train of thought. On a cat with twin electric drives, you get precise handling in tight spots because of the low rpm torque of an electric motor coupled to large diameter and pitched props. Your concept of only needing max power for short duration is spot on, and that is the beauty of an electric, most will give 4 to 5 times cont power for a thermal limited time frame. An added feature is the motor has the same high efficiency throughout its power range, whereas a diesel is only efficient (if you can call it that) at 3/4's throttle and at the torque peak rpm. When using a DC gen set, you save a lot of weight over a conventional 120/240 VAC 60 cycle generator, at the 20Kw level, better than a 200+ lb savings and you have the flexibility of placing this weight where it is a low and balanced load in your hull. You just run your inverter off the propulsion bank and the output of the diesel DC gen set is the DC charging voltage for the bank. I will be using a 48 volt bank because you still have choices for a good price on mass produced inverters that run on that voltage. And when you kick on that 1200 watt galley appliance, instead of pulling 100 amps on the DC side at 12 volts, your pulling 25 amps at 48 volts.

This sounds great but have you factored Inthe drag of the two large diameter props while sailing? I would estimate maybe a 2+ knot loss of speed for this which means you would probably have to motor a lot more. For your future boat, a PDQ 36 wouldn't the Torqueedo motors with there ability to tilt free of the water while sailing make more sense?

[MacG]

@ Dockhead

Precisely my thoughts in favour of electric propulsion. In this particular schedule you are as flexible as with a heavy diesel meanwhile saving energy where possible.
In the rare occurrence of a heavy storm you have always your trysail as way of help.