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Diesel-electric hybrid

12K views 77 replies 22 participants last post by  deckofficer 
#1 ·
Searching for you folks that have already converted to diesel electric. My plans are for a 48 volt propulsion/house bank, 48 volt inverter, and diesel DC gen set. I am comfortable with electrics, have designed, built, and raced EVs.
 
#2 · (Edited)
Unless you are planning to run submerged, I would not bother.

Every time you change energy from one form to another, you will suffer losses. Batteries, particularly lead-acid accumulators, are notoriously innefficient at storing energy, and recovering it again.

Diesel-electrics are often seen on rail locomotives, largely because of coupling issues as it is so difficult to get drive to multiple wheels with mechanical drive.

But on a sailboat??? Your diesel engine will give you about 40+% efficiency, and the tank fuel will take you far further than the most massive of battery banks, battery banks that slowly lose poke as they are cycled.

And what size of generator are you going to need for (say) 35 hp at the prop?

I warn you too, with seawater-wet hands, 48 V will make life very exciting for you. It is exciting enough with nominal 12 V. Try it.
.
 
#4 ·
The displacement at cruise weight will only be 8500~9000 lbs, so electric propulsion will only need to be in the 8~12Kw range. I hope to not even use the diesel much, but as a cruiser I want the option of running from a storm for days, not hours. The diesel gen set will output DC for charging only, because it would be much heavier (and redundant) for it to be a typical 120/240 VAC 60 Hertz unit when a 48 volt input inverter is part of the system. A hybrid system such as this has a lot of advantages.

1) weight placement flexible for better balance and trim
2) The low rpm torque capabilities of an electric motor for tight quarter maneuvering is sweet.
3) The weight is an even wash with the components I've sourced.
4) I've always wanted a fully electric galley, from the induction cook top all the way to the 1500 watt rail mounted BBQ.
5) Even the dinghy will be electric, never have been a fan of gasoline and propane.
6) I have a personal reason too, the DC diesel gen set can be fueled with renewable fuels, and after working in the oil industry, I have a strong disdain for them and their product.

So, I'm doing it, no need to try and talk me out of it. Is there anyone on the forum who has also converted over to diesel-electric hybrid drive?
 
#5 ·
The displacement at cruise weight will only be 8500~9000 lbs, so electric propulsion will only need to be in the 8~12Kw range. I hope to not even use the diesel much, but as a cruiser I want the option of running from a storm for days, not hours. The diesel gen set will output DC for charging only, because it would be much heavier (and redundant) for it to be a typical 120/240 VAC 60 Hertz unit when a 48 volt input inverter is part of the system. A hybrid system such as this has a lot of advantages.

1) weight placement flexible for better balance and trim
2) The low rpm torque capabilities of an electric motor for tight quarter maneuvering is sweet.
3) The weight is an even wash with the components I've sourced.
4) I've always wanted a fully electric galley, from the induction cook top all the way to the 1500 watt rail mounted BBQ.
5) Even the dinghy will be electric, never have been a fan of gasoline and propane.
6) I have a personal reason too, the DC diesel gen set can be fueled with renewable fuels, and after working in the oil industry, I have a strong disdain for them and their product.

So, I'm doing it, no need to try and talk me out of it. Is there anyone on the forum who has also converted over to diesel-electric hybrid drive?
That's a good point. The ability to heat water, power winches, make water, heck even use an electric blanket. All while carrying only one kind of fuel.
I would definitely sacrifice a little power to be able to have the convenience of all the extras.
Plus, I bet it would be a lot easier and less trouble to maintain or replace a small generator rather than an inboard diesel.
 
#7 ·
Hey deckofficer, I've been around boats for 40 years and reading about the system that you are describing, it seems to me that you will be in a world of hurt in the short run. When it comes to boats I firmly believe in the KISS method. You're sitting in a fiberglass tub surrounded by saltwater and its always humid with a fog of salt. When it comes to boats Murphy was absolutely right. What's more if you're in a sailboat, sail the damned thing, that's how you get better at it. Installing complicated systems in a boat takes you away from what you should be doing with it.....sailing. I owned a J24 for nine years and I think we used the kicker three times and then only because we had to.

Anyway, good luck with all that....I think you'll need it.
 
#9 ·
Hey deckofficer, I've been around boats for 40 years and reading about the system that you are describing, it seems to me that you will be in a world of hurt in the short run. When it comes to boats I firmly believe in the KISS method. You're sitting in a fiberglass tub surrounded by saltwater and its always humid with a fog of salt. When it comes to boats Murphy was absolutely right. What's more if you're in a sailboat, sail the damned thing, that's how you get better at it. Installing complicated systems in a boat takes you away from what you should be doing with it.....sailing. I owned a J24 for nine years and I think we used the kicker three times and then only because we had to.

Anyway, good luck with all that....I think you'll need it.
I'd much rather sail too. The systems are not complicated, just different. This is for a PDQ 36, that isn't the LRC, but lets say it is the LRC. (3) diesels, (2) for propulsion when needed, and all the through hulls for that, one for running high wattage AC appliances at 120/240 60 cycle. All I am doing by going with the non LRC model is swapping (2) Yamaha 9.9 gasser outboards with electric outboards, and instead of having a heavy gen set for AC, going to a much lighter gen set for DC only to charge the propulsion/house batteries as they need it. I hope to not even run the DC gen set much, with solar panels and regen from either motor if left in the down position while under sail.
 
#8 ·
I am intrigued and would lovbe to find an alternative propulsion system. One of my friends is interested in converting also to a mastervolt system similar to what you are describing.

So a generator and the large battery bank only weighs 300 lbs? Explain how you come up with that figure?

Dave
 
#10 ·
You wrote "running high wattage AC appliances at 120/240 60 cycle"

Whoa, so what you're telling me is that you're sailing a condominium, Hmmmmmm. I guess my general advice is falling on deaf ears. I once knew some folks who owned a Bristol 36 with all the bells and whistles...hell, I think the thing even sported a trash compactor. Anyway, they loved that boat until it started to s_it the bed on a regular basis and they spent many a beautiful weekend tied to the dock trying to fix the trash compactor or whatever, rather than sail. They never did learn how to sail that damned thing.

Bon chance, my friend.
 
#11 ·
Maybe I'm not explaining my intentions very well. I love to sail, and on my old Cal 40 had minimum systems to contend with. I'm quite a bit older now and like certain creature comforts. I don't want or need a trash compactor, washer-dryer, etc., but do want a microwave (who doesn't) and a REAL watermaker that doesn't require constant membrane replacement, noisy, and low output of the 12 VDC types that are available. This means clean, reliable AC power, which is what pure sine wave inverters are for. Plus on the efficiency side, a diesel engine with its weak kneed torque curve is very inefficient at any rpm other than at the peak torque rpm. An electric motor is efficient through out its operating rpm range. The last ship (rig) I served on was a 32,000 ton off-shore drill ship that I held position over the hole with (6) 5000 hp electric motors. I had (7) 4.6 Mw generators that ran at their torque peak of 900 rpm (also divisible by 60 for frequency). If enviormental loads where high, i.e. 40 kt wind and 3 kt current, I could burn 1,000 gallons of diesel per hour to hold position. That may not sound efficient, but believe me if not diesel electric, it would consume much more, but again it couldn't be done without the low rpm torque of an electric motor. An electric has all available torque at 0 rpm, no IC engine can even come close.

To address Chef2Sail question on weight, it is expensive to keep the weight down, as you need to use LiFePO4 batteries. These cells, with proper care will have a 5000 cycle life at 80% DOD, so at my age, will outlast me. The diesel gen set is a large weight saver if you chose a unit that is a PM DC output over a conventional AC gen set.

This is a picture of that ship (rig) I described. Unlike Captain "Showboat" Schettino, my ship is butt ugly, so no need to salute an island with it. It is a diesel-electric hybrid, but mine will be scaled down a bit.
 
#15 ·
There are a number of electric outboards currently available with new ones coming to market. The Torqeedo 4.0, a 4Kw unit from Germany is expensive and they are missing the boat (no pun intended) by not having regen. The amount of thrust matches a 9.9, which is what is used on PDQ 36s. AquaWatt outboards have the physical dimensions of a 9.9 and come in two flavors, a 13Kw (a pair of these are over kill on the PDQ) and a 23Kw.

aquawatt green power electric outboard motors

Note the weight difference between these DC gen sets vs an AC gen set. You won't find an 8Kw AC diesel gen set for 290 lbs like this DC unit.

http://www.propulsionmarine.com/wp-content/uploads/2011/02/8-KW-Polar-DC-Marine-Brochure.pdf
 
#17 ·
Intresting and informative thread. Thanks. A freind was telling me about a electric sail drive out now that charges back into it's system when sailing. Motor/generator? can't remember the make darn it. check this one out... Vetus Electric Drive EP2200 - French Marine Motors Ltd
 
#20 ·
I applaud your approach, and while I am not ready for the leap to electric sailboat motors it will take you and others to keep plugging at making it work for the rest of us.

I have an on-line friend in SF Bay who has converted a 25ft double-ender to a 48volt electric system recharging at dock and reports usable power to the electric motor for at least 8hrs.
 
#21 ·
I chartered one of the Lagoon hybrid drives a few years back. Loved it! To be able to move w/o firing up a motor was fun. The genset was very quiet when fired up.
I have been researching converting our boat when the volvo becomes an anchor.
Please keep us informed
Jim
 
#22 ·
Ulladh,

Thanks for your support, I still hope to find folks here that have already converted. On CF, there are 6 that are active on the forum, and most are cats. They were able to confirm my theory that the high torque at rpms that a diesel can't even idle at, would make tight quarters maneuverability child's play. So I guess all the bar patrons at the marina will have less entertainment watching boats at the docks trying to pirouette into position.
 
#23 ·
Jim,

Did you also discover how the electric motors allow precision maneuverability, so you always look polished to on-lookers as you pull in?

I will keep you posted because for me it is a combination of loving sailing, hating the oil companies, and designing and racing EVs. For the EVs, quiet power is a rush, and a real head turner.
 
#24 ·
Jim :

I will keep you posted because for me it is a combination of loving sailing, hating the oil companies, and designing and racing EVs. For the EVs, quiet power is a rush, and a real head turner.

Your attitude to oil companies surprises me, and is somewhat alienating.

You are typiing on a plastic keyboard, looking at a plastic screen, on a varnished desk, pictured in a motor vehicle painted with oil-based paint, driving on roads finished with bitumen, owning a sailboat made from polyester resins painted with petroleum products, living in a house painted with petroleum and plastics everywhere, planning a hybrid propulsion that will not move without a petroleum-driven generator... and you hate oil companies????

Take your hatred of oil companies a step further and stop using petroleum.

Give it a go.
 
#25 ·
Hybrids and hating oil companies

"hate" is a strong word but, using it is the same way as deckofficer, I hate X Factor but still find myself drawn to the train-wreck-slowly-unfolding nature of the show.

Anyhow, he did not say he hates oil, probably just the way in which companies active in that business conduct themselves. I doubt it is a rationally thought through opinion so much as a visceral sense that helps justify an otherwise admirable plan to test the limits of providing power to a sailboat.

I have a friend who is trying what deckofficer proposes and will ask for some feedback on his success. I do know that he found the regen to cut into performance more than he expected, because instead of the propeller spinning free, it was dragging with resistance - he reckoned he lost 2 kts. May be worth exploring whether regen through your motor is more of a parasitic load than a wind generator up above - which is what I think he ended up with.

400 watts of solar panels was way too expensive but I recall that he did not have a huge capacity to charge so solar might have worked if it was cheaper (and no parasitic load). The main benefit was the efficiency of the generator operating at optimum versus a diesel operating outside its efficient range.

I will post anything else I find out, or better still, persuade him to join sailnet if he is not already a member - I am new to this "social media" thing so coming to sailnet late in my sailing life (although hopefully with more life left in me than a new lithium ion pack)
 
#27 · (Edited)
44.8" X 7.17" X 10.98" 196.8 lbs. 9.2 Kw/hr 48 volt bank. I come by my attitude towards oil companies honestly, I used to work for them. I will have lots of solar since China has entered the market and driven the cost down to $1.13 per watt from the $5+ per watt I last paid.

As to drag, the water medium does not care if your using energy for propulsion or receiving energy from being propelled by your sails. The folks that are using diesel-electric drive just run the motors to match what they calculated their boat speed to be for the conditions. Nice thing about doing that, you are assured of your ETA to anchorage, and depending on if you under estimated or over estimated, your battery bank will have less or more SOC when you arrive. Plus, you have the option as you near landfall, if you know you will be on the hook for awhile, just back the pots down, induce more drag, and fully top off the battery bank.
 
#28 · (Edited)
Nobody suggesting dishonest hatred of oil companies. However, not worth discussing further since that is off topic.

I am not sure I understood the relevance of your second point. You seem to be saying that if you run the motor consistent with the speed you think you are going, then at least you know when you will get there and that if you calculated right then your level of charge will be unchanged at the end of the voyage. ie you did not charge the batteries

My friend was trying to harness the kinetic energy of the boat to charge the batteries so he had maneuvring power at his arrival without expending diesel to provide it. Converting kinetic energy into electrical energy without a loss of boat speed compared to letting the prop spin free (since the mass stays constant for all practical purposes) results in drag which slows the boat. In the limiting case, a prop stall, you will see the difference it makes to your boat speed. A wind turbine or (as you rightly say, now cheaper) solar cells result in less parasitic load. He went for the former -- a wind turbine.
 
#29 ·
Telesail :

If oil company bashing is off topic then keep it off-topic.

I see it too often, and on this website.

I am an oil engineer, and I hear no complaint AT ALL when the users of petroleum drive into their station forecourt and fill up their Suburban to the cap with petroleum, then drive off towing their boat with no thought at all as to the men and women that put it there.

When the oil men and women DIE putting it there, and 11 of them did last summer, all I hear is high-volume oil-company bashing about oil on beaches.

If you don't like petroleum, then don't use it.

I am going to have the last laugh watching you try, and I can tell you that our oil-company-hating friend there with his diesel electric won't get far without it.

So let's all stay on topic then, shall we?, and leave oil-company bashing to those that don't use petroleum.
.
 
#30 ·
The off topic bit was whether deck's hatred was dishonest or not. I personally think he is misguided and generalizing from some specific experience. I am not an oil company basher -- quite the opposite. Happy to have a discussion about the social and economic good that the oil and gas industry provides (and the occasions on which it falls short of its standards) compared to many alternative energy schemes.

However, I was trying to respond to the point about no loss of speed from regenerative charging rather than arguing with someone whose mind is obviously made up about why he feels the way he does.
 
#31 ·
Ok, sorry folks, I should have never expressed my disdain for the oil industry. I used to work in the industry and didn't care too much for the corporate attitude. I will be careful to stay on topic so that others who have converted and folks thinking about converting don't have to wade through the distractions.
 
#33 · (Edited)
I will be careful to stay on topic so that others who have converted and folks thinking about converting don't have to wade through the distractions.
Thanks for that Officer.
I think what you are doing is very interesting.

Another benefit to your plan that may not have been mentioned is that your diesel should last practically for ever. Can I assume it will either be off or running at optimal load? If so it is stark contract to a normal sailboat auxiliary that is typically running at anything but optimal load. While I doubt that you will pick up all conversion losses by running at optimum load 100 percent of the time I suspect you will pick up a significant percent of them.

Another potential benefit is that the diesel can be easily insulated for sound.

Another benefit is that you may be able to locate it in such a way that access is easy.

As you said it is different and because it is different it will have advantages and disadvantages not necessarily predictable from the start.

You sound like the guy to make it happen and please document the process we are interested.
If you don't mind please let us know what parts you are currently considering:

Electric Drive motor
Prop
Generator
Battery's models
Charge controllers
Monitoring
Inverter
Expected loads
Boat model, displacement and year so we have it all in one place.
Anything I have missed

If you go through all the trouble of outlining the sources, costs, models, weight, calculations etc for your current candidate parts in one place I for one would be willing to help in researching optional components and things to think about. Also other sailnet members may have experience with specific parts even if used in a more traditional way.

If you don't want to be bothered I understand but there are some very talented people here and maybe it would be worth your time even if you get just one good idea.
Also I have the ABYC book so can look stuff up if you don't have it and my son just passed the ABYC electrical exam so I can hit him up for what is the current thinking.

If you don't know of these guys you may find some information from them.
I find the format prehistoric as opposed to a standard forum but yahoo groups has a feed for electric boats that has been around for many years.
electricboats@yahoogroups.com
 
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