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Electric repowering?

supersailor

Contributing Partner
Stephen,

The problem is hull speed. A lot of energy goes into creating that last knot or so. That hole you are creating in the water costs a lot of energy. My 34-2 only takes about 2hp to do 3.2kn but 23hpto do 6.5kn. If you are willing to go slow, the electric will do. Fast, only diesel will work.

We will have to wait for the next improvement in batteries to work for us here in The North-West. Lack of range and slow recharging are the biggies. Mounting a genset makes for a complicated, expensive installation. Using a portable genset anywhere on the boat is playing roulette with your life.
 

texlan

Member I
Blogs Author
Christian, I have mad respect for you by the way.

The capability side that you generally do not have with a diesel alone:
  • 5.5kw of AC available + the 5000va quattro, which can supplement from the battery and give you a short term ~10kw peak AC load handling ability. Nothing to sneeze at. You can eliminate propane/alcohol stoves. I'm not a greenie, I just don't like things that have an explosive failure mode.
  • Air conditioner at anchor -- not a big deal for you in so cal or PNE, but in Arizona summers... brutal trying to sleep in 95 degree 50% humidity weather, even with fans. Yes you could do AC, kind of, with a diesel+alternator+inverter, but you can't set up auto-start with that to automatically maintain a battery state of charge profile like you can with a genset. And you have to size the inverter for the start loads... and the batteries..and the wires...with a 'hybrid' setup you already have all of this in place, and you have a genset.
  • Normal house loads can be handled from the 48V propulsion bank via filtered (ie not noisy) and sealed regulator(s), and propulsion banks tend to be larger than standard house banks, so you can go longer between needing to charge them at anchor. 12V starting battery kept floating by same types of regulator.
  • Not if, but when, you have problems with your diesel, with the prime mover being electric you still have options. Where you otherwise would have to call a tow because of a bunk exhaust elbow or water in the fuel (and no more filters,) you now have the ability to limp in. OR blast in, depending on the state of your batteries are when you discover the problem, but I assume prudence would dictate that you don't purposely run your bank below 50%. And solar is a significant source of energy.. on my little 26 at the lake I can maintain about 2.8kts on solar alone. Yeah -- it's in calm seas. But if there was weather I would let that solar charge that bank while I sailed toward safe harbor, then use the stored power to get to the mooring/drop the anchor/get into the marina with authority. It may be a little inconvenient but not as inconvenient as having no option but a tow.
  • The normal plusses of electric.. instant on, full power available. Relatively little maintenance of the prime mover.

Now this said, it's not magic fairy dust and you do need to take a fairly methodical approach to designing your systems so that it all comes together reliably. You need to read maine sail's articles on proper marine electrical connections :) You need to get the right tools. You need to look at the available ABYC standards and adhere to them.

There are more individual pieces that can fail in the "ideal long-range energy source-to-propulsion path," (fueltank->engine->transmission->propshaft vs. fueltank->engine->generator head->charger->battery->motor controller->motor->gear reduction->propshaft) but there are more paths with the hybrid solution, and as along as the (traditionally very reliable) battery->motor controller->motor->gear reduction->prop shaft path is working, (And individual components are not unreasonably expensive, and spare controllers, belts, motor could be reasonably kept on a longer-term cruising boat,) energy source can be genset, wind, solar, fuel cell, dragged generator, .. ? Anyways, I enjoy this stuff, and have a good understanding of electrical and emergency power management as an extra class licensed radio amateur. For me it's a great fit, but not necessarily for everyone, and I understand that.

Because of the benefits from a systems perspective, I think integrated hybrid approaches like this are going to become more and more common from manufacturers, because they provide a more solid electrical foundation to the never ending desire for the comforts of home -- microwaves washing machines and all sorts of silliness (For the record, the fiance wants a microwave..hmm, maybe not so silly if I want her to go voyaging with me). A 45-60lb prime mover and reduction gear/belt drive are a lot easier to install and align to a prop shaft than a 300 lb iC engine. Lot easier/cheaper to replace, too.

Supersailor is absolutely right by the way.. it generally takes a little more than double the power to go an additional knot. so 3 knots may take my little 26' 400 watts. But it takes 1000 to make 4 and 1800 gets me 4.7ish..

Sorry for the book by the way !

Sean
WK7R
 
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Christian Williams

E381 - Los Angeles
Senior Moderator
Blogs Author
Good thinking, the detail is appreciated by everybody. And of course as a Prius owner I entirely get hybrids.

The primary need for an engine on my boat is propulsion with 500-mile range, and a 100 amp alternator for one-hour daily recharge of house bank.

I do think you underrate the reliability of yacht diesels, even under the most harsh conditions, and of course your genset is a diesel.
 

steven

Sustaining Member
hybrid electric ?

Taking another look at this.

Anyone have insight into how to hook up a genset for hybrid ?

The e motors I'm looking at tend to be in the 48v 60amp DC range (around 3kw) .

Can this be driven direct with a genset without going through the battery bank ?
Would you use a 30amp 110v AC outlet from the genset and put it through an AC to DC power supply to get the 48v/60a ?


thanks

--Steve
 

gadangit

Member III
Taking another look at this.

Anyone have insight into how to hook up a genset for hybrid ?

The e motors I'm looking at tend to be in the 48v 60amp DC range (around 3kw) .

Can this be driven direct with a genset without going through the battery bank ?
Would you use a 30amp 110v AC outlet from the genset and put it through an AC to DC power supply to get the 48v/60a ?


thanks

--Steve

Have you considered a 48VDC generator? That would match the voltage of your largest load. From there all of your voltage conversion devices could be sized for their load and in theory be smaller.

Can you describe your proposed system a bit better? House bank and how to charge, propulsion bank and how to charge, solar, etc...
 

kiwisailor

Member III
Blogs Author
Diesel Electric for Boats

For years trains have been using diesel electric traction. I can see major benefits of moving this way in boats. The engine/generator can be located away from the drive motor and allow for optimal installation locations. Don't get me going on Ward Leonard speed control from back in my electrical engineering study days, today it is all power electronics control.

With the development of power electronics for motor speed control it would be possible to use DC traction motors (brush less) or another option is to use a low cost squirrel cage induction motor, these motors are relatively cheap and easily sourced globally.

https://www.acdrivesguide.com/squirrel-cage-induction-motor
 

nquigley

Sustaining Member
Christian, I have mad respect for you by the way.

The capability side that you generally do not have with a diesel alone:
  • 5.5kw of AC available + the 5000va quattro, which can supplement from the battery and give you a short term ~10kw peak AC load handling ability. Nothing to sneeze at. You can eliminate propane/alcohol stoves. I'm not a greenie, I just don't like things that have an explosive failure mode.
  • Air conditioner at anchor -- not a big deal for you in so cal or PNE, but in Arizona summers... brutal trying to sleep in 95 degree 50% humidity weather, even with fans. Yes you could do AC, kind of, with a diesel+alternator+inverter, but you can't set up auto-start with that to automatically maintain a battery state of charge profile like you can with a genset. And you have to size the inverter for the start loads... and the batteries..and the wires...with a 'hybrid' setup you already have all of this in place, and you have a genset.
  • Normal house loads can be handled from the 48V propulsion bank via filtered (ie not noisy) and sealed regulator(s), and propulsion banks tend to be larger than standard house banks, so you can go longer between needing to charge them at anchor. 12V starting battery kept floating by same types of regulator.
  • Not if, but when, you have problems with your diesel, with the prime mover being electric you still have options. Where you otherwise would have to call a tow because of a bunk exhaust elbow or water in the fuel (and no more filters,) you now have the ability to limp in. OR blast in, depending on the state of your batteries are when you discover the problem, but I assume prudence would dictate that you don't purposely run your bank below 50%. And solar is a significant source of energy.. on my little 26 at the lake I can maintain about 2.8kts on solar alone. Yeah -- it's in calm seas. But if there was weather I would let that solar charge that bank while I sailed toward safe harbor, then use the stored power to get to the mooring/drop the anchor/get into the marina with authority. It may be a little inconvenient but not as inconvenient as having no option but a tow.
  • The normal plusses of electric.. instant on, full power available. Relatively little maintenance of the prime mover.

Now this said, it's not magic fairy dust and you do need to take a fairly methodical approach to designing your systems so that it all comes together reliably. You need to read maine sail's articles on proper marine electrical connections :) You need to get the right tools. You need to look at the available ABYC standards and adhere to them.

There are more individual pieces that can fail in the "ideal long-range energy source-to-propulsion path," (fueltank->engine->transmission->propshaft vs. fueltank->engine->generator head->charger->battery->motor controller->motor->gear reduction->propshaft) but there are more paths with the hybrid solution, and as along as the (traditionally very reliable) battery->motor controller->motor->gear reduction->prop shaft path is working, (And individual components are not unreasonably expensive, and spare controllers, belts, motor could be reasonably kept on a longer-term cruising boat,) energy source can be genset, wind, solar, fuel cell, dragged generator, .. ? Anyways, I enjoy this stuff, and have a good understanding of electrical and emergency power management as an extra class licensed radio amateur. For me it's a great fit, but not necessarily for everyone, and I understand that.

Because of the benefits from a systems perspective, I think integrated hybrid approaches like this are going to become more and more common from manufacturers, because they provide a more solid electrical foundation to the never ending desire for the comforts of home -- microwaves washing machines and all sorts of silliness (For the record, the fiance wants a microwave..hmm, maybe not so silly if I want her to go voyaging with me). A 45-60lb prime mover and reduction gear/belt drive are a lot easier to install and align to a prop shaft than a 300 lb iC engine. Lot easier/cheaper to replace, too.

Supersailor is absolutely right by the way.. it generally takes a little more than double the power to go an additional knot. so 3 knots may take my little 26' 400 watts. But it takes 1000 to make 4 and 1800 gets me 4.7ish..

Sorry for the book by the way !

Sean
WK7R
If you haven't seen it already, you might skim through the video blog on You Tube called 'Sailing Uma'. It's now a 3-year cruising channel, so you have to pick your way through to find the handful of episodes that deal specifically with the issues and solutions they encountered with their all-electric system, on a Pearson 36. Most of the power-related episodes seem to be in their first 2 years. They eventually converted to a 24V system, and a new bank of corresponding (and very expensive) batteries, but after 3 years, I think they're still using the forklift electric engine they installed when they first started.
It seems to me that the diesel vs. electric decision is dictated largely by the way in which one needs/uses auxiliary propulsion. The Sailing Uma couple seldom motors more than ~30 min at a time - mainly just in and out of awkward anchorages. But, blue water cruisers sometimes need to do 6-8 hours of continuous motoring to get away from forecasted bad weather or to get out of no-wind zones - often when there's not enough sun for good solar charging or enough wind for wind-power generators. The Sailing Uma people are planning a trans-Atlantic voyage this year - it'll be interesting to see how they make out on an all-electric boat.
 

steven

Sustaining Member
Use is in-shore. Hanging around the Chesapeake.

The motor part is easy. Lots of choices.
Challenge is the genset.
Who makes a genset (generator + built in AC to DC) with output DC 48v 60a (or 36v 80a; or 24v 120a)?
By the way, any fuel would be ok.


ZAA==



thanks
--Steve
 

gadangit

Member III
Use is in-shore. Hanging around the Chesapeake.

The motor part is easy. Lots of choices.
Challenge is the genset.
Who makes a genset (generator + built in AC to DC) with output DC 48v 60a (or 36v 80a; or 24v 120a)?
By the way, any fuel would be ok.

thanks
--Steve
I have a Fischer Panda 6kW that outputs 48VDC (56.5VDC is actual output voltage). I told my genset rep what I wanted and he did the rest. You could probably get almost any genset manufacturer in 48VDC if you ask.

That is tied to a common 48VDC bus along with a battery string, solar charger and shore power charger (that I never use). Loads off bus include Sevcon VFD, Watermaker high pressure pump, 48VDC:12VDC converter for house battery and an inverter. I'd hang more off the bus if I could find more things in 48VDC.

I've run this motor/genset crossing the gulf and moving around locally for hours and hours at a time. Cooling is the biggest issue to overcome.
 

steven

Sustaining Member
Chris,

Thanks. That sounds like it will work.
Fischer Panda is a bit pricey so I'm shopping around on the genset.

--Steve
 

gadangit

Member III
Yeah, I agree. I happened to have a friend who sells them, so I got it at cost.
Good luck, let me know if you have any more questions.
Chris
 

Teranodon

Member III
The minuses outweigh the pluses here in the Pacific North West.


I agree with Bob, but I'm beginning to think that there may be an electric outboard in my future. I just don't trust those 4-stroke engines. I'm already dreading the spring maintenance on my Nissan. I would be interested in hearing from any Forum members about their experiences with electric.

And, to Christian's point: a coupe of years ago, I removed the dodger for the winter, and just didn't bother putting it back on. Now I'm not sure I ever will. The weather around here just isn't that bad very often. And visibility from the helm is much, much, much better without the thing. Plus, the boat looks faster, even on a mooring.

And this for the benefit of those who have never seen an Ericson 34/35/38 without a dodger:

Talpa on Jones.jpg
 
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