Electric Drive: Who uses it?

[PeterSz]

I’m definitely not an expert with electric engines and I’m not an engineer either but...
I have a 53hp yanmar and a 150l diesel tank. I can travel around 250nm or so, at 7knots speed (it’s a rough calculation).
I can’t really se realistically doing the same with electric engine and batteries.

However, I’m still thinking to convert my boat to electric, ones the diesel give up.
Reasons
1. Much less moving parts
2. Simplicity
3. No transmission
4. No oil changes
5. No exhaust system
6. No water cooling system
7. No holes on the hull
8. No laud noise
Just to name a few...

People hate this idea who want to make big distance in a short time. For others it’s not the priority and that’s why they find converting to electric is more attractive.

I find it funny how far people go to convince each other about their true but the fact is that if something doesn’t work for you it might work for me. As we all have different needs and there is no two people would use their boat in the exact same way.

[Dockhead]

Originally Posted by PeterSz

I’m definitely not an expert with electric engines and I’m not an engineer either but...
I have a 53hp yanmar and a 150l diesel tank. I can travel around 250nm or so, at 7knots speed (it’s a rough calculation).
I can’t really se realistically doing the same with electric engine and batteries.

However, I’m still thinking to convert my boat to electric, ones the diesel give up.
Reasons
1. Much less moving parts
2. Simplicity
3. No transmission
4. No oil changes
5. No exhaust system
6. No water cooling system
7. No holes on the hull
8. No laud noise
Just to name a few...

People hate this idea who want to make big distance in a short time. For others it’s not the priority and that’s why they find converting to electric is more attractive.

I find it funny how far people go to convince each other about their true but the fact is that if something doesn’t work for you it might work for me. As we all have different needs and there is no two people would use their boat in the exact same way.

I think we can all agree about that!

If it works for you, more power to you!

It's just important to be realistic what you can do with electric propulsion at the current state of the art. If you are, and that suits you, then great! And be sure to tell us about your experiences, because real life experience is much more valuable than theory.

[ranger58sb]

Originally Posted by storx

Both of the diesel engines were heavily damaged according to him and would need to be rebuilt due to sea water entering the internals of the engines. When he had a mechanic price him on rebuilding and bringing both of the drive motors back up to shape it was in the ballpark of 30-40k he told me. So he sat on the idea of buying the boat from the owner and haggled him down on the price heavily to make it worth his time, plus in his mind he said if he would have rebuilt the diesel drive motors that he would have had a fresh engine boat for less than some of the boats he looked at with already running engines in similar shape elsewhere outside of the engine room.

He told me he has less than 20k into his entire conversion from diesel drive to electric with the giant increase in battery storage with the tesla modules after taking out the money he got back from selling the old diesel engines. He also mentioned he has sold a handful of items off the tesla car to people for a few k along the way. His only reason for not increasing his battery bank is he said the prices of tesla's at the auctions has nearly doubled in price on totaled cars, with everyone wanting the batteries now the value of them has increased out of the range he is willing to pay for, but he keeps bidding on them with the hopes of scoring another for more modules.

Also a correction, i thought he said it was 41ft, he said his boat is a 44ft defever, not 41.. that he purchased it for 27k

Interesting science project. What were the original diesel engines? What would have been the net cost (after selling off the originals) of replacing those with reman Cummins (for example) of equivalent horsepower? (Looks like twin 135-hp Perkins diesels were typical. I'm surprised at the $30-40K rebuild estimate; that sounds more like for big DDs...)

Sounds to me like he's got a 44 Defever worth about $30K as potential resale after the electric conversion, whereas he might have had a 44 Defever worth maybe $150K or more depending on model year (? just a guess) if he had either rebuilt the old diesels or replaced the old diesels with new. (The average on yachtworld just now looks like around $180K ballpark.)

-Chris

[skipmac]

Originally Posted by storx

Wow,

I didnt expect people to take this posting personal, calling me an idiot is a little childish....

Unfortunately on any public forum you're almost certain to run into one or two members with bad manners. I try to ignore them and focus on the positive replies and the good information on the forum.

Originally Posted by storx

So after a lot of research he bought electric motors roughly equal in output to the diesel motors that where on the boat, he mentioned they were curtis motors with rated output of 190hp @144v each with controllers in a kit for 15k and he payed another 1k for the converter that converted the output voltage from the diesel generator he had so he could input the correct power from the generator directly to the electric motor circuit.

And here is the big problem with his conversion and the savings he claims with electric. To run two 190 HP electric motors even at 25% power will take a 75 kW generator. The cost of a generator that large by itself will be more than the $30-$40k to rebuild the two diesels. If he wants a generator that allows full power to the motors off the generator it would cost more than the boat is worth.

[Dockhead]

Originally Posted by storx

Wow,

I didnt expect people to take this posting personal, calling me an idiot is a little childish....

Did someone call you an idiot? Really? If so, please immediately report that post. That is not allowed on here -- vigorous debate is allowed, but personal insults are absolutely not allowed.

[valhalla360]

Originally Posted by CaptFrankM

At the risk of going WAY OFF TOPIC, I would point out that there were "boats" that used a hybrid electric/diesel system going back more than 100 years. They were submarines and used a diesel generator on the surface, batteries while submerged to get places.

Similarly, there are (I believe) catamarans that use a diesel in the bow area of one of the amas and electric motors in the stern of the amas for propulsion.

I cycle back to my original point - if the boat is designed for electric propulsion from the get-go, it can be a very effective (not necessarily efficient) propulsion system. The devil is in the details.

Subs are a totally different use case. You simply can't run the diesels when submerged, so they aren't an option for diving. They weren't more efficient for surface ships.

I'm curious what catamaran you are talking about. One of the major manufacturers did one 15-20yrs back but I believe most eventually got converted to straight diesels. I don't think the diesel was in the bow.

[a64pilot]

The Chevy Volt is most certainly a Hybrid, there are different types of hybrids.
The WWI and II subs are hybrids also.
https://auto.howstuffworks.com/diffe...brid-cars1.htm


For those interested in how a Prius “transmission” works Read here.
It’s not a transmission actually, there is only one mechanical gear and no neutral or reverse, it’s a “power split device” as Toyota calls it.
Reason for posting this, is read above on how the Volt works, and here on how the Prius operates, and you will see these things are absolute marvels of mechanical genius, and there is a whole lot more going on than just an electric motor. This is just the mechanical aspects of the Prius, there are five separate operating stages the computer puts it into, and finally it’s not even an Otto cycle engine, but an Atkinson cycle engine.

Back to there is a WHOLE lot more going on than just an electric motor.
http://prius.ecrostech.com/original/...OnAsIDrive.htm

[Lost Horizons]

Originally Posted by valhalla360

No, the thread is about electric drivetrains. In fact the starting post talked about a trawler converted to electric drives
I readily agree that if you are a purist who rarely if ever motors any significant distance, it's possible.

I missed the part that it is a powerboat section. Yes, electric trawlers are not practical with current technology.

[john61ct]

Wow, now I got a bad case of whiplash. 8-)

[valhalla360]

Originally Posted by storx

Wow,

I didnt expect people to take this posting personal, calling me an idiot is a little childish....
I went back and looked at my posts and I didn't find any where I called you an idiot. I did indicate you may have misunderstood what your friends are telling you or possibly they didn't understand the information they gave you. If you misconstrued my post to indicate that you are an idiot, I apologize as that was not the intent.

In regards to my Car that i brought up previously, 2012 Chevy Volt.

The chevy volt is NOT a hybrid, it is an electric car with gas range extension. The electric motor powering the wheels is used both when pulling power from the batteries or when receiving electrical power from the gas engine. The gas engine is not connected to the wheels in any way except via electrically.
This clearly meets the definition of a hybrid. As others have pointed out there are different hybrid configurations.

The electric motor powering the car is 150hp/275tq rating at 0rpms. Sorry but HP = torque * RPM, so if rpm = 0 HP = 0. The ratings are peak outputs (though for an electric motor, torque is pretty much consistent across the RPM range.

The gas engine onboard is 78hp/61tq rating at 6300rpms. The gas engine turns a 2nd electric motor rated at 55kw, to generate power for the drive electric motor to continue driving. When i am cruising here in Florida on I75, my gas engine rpms typically run just under 900rpms according to the display for me maintain a cruise control speed of 75MPH. Basically i have 275lbs of tq on tap to be used instead of the 61lbs of tq the gas engine puts out at 6300rpms. Again something isn't right. If the gas engine peaks at 61ft-lb assuming it is generating that at 900rpm (typically idle speed torque will be less), that calculates out to 10.5hp. Not a chance you are running 75mph on 10.5hp. Is it maybe getting most of the power from the battery with a supplement from the gas motor?

In regards to folks calling me an idiot for wanting to ruin a boat by converting it to electric and adding a bunch of weight. I did not state i was the owner of an electric boat, i did not tell or say i was going to convert one to electric. I purely asked if anyone else was using them, i had never heard of a boat being powered by electric motors before and was curious how many others out there are trying it out.

In regards to the electric vehicles i brought up, i have friends in the mining industry up in canada, he has told me about all these vehicles they have recently replaced with electric versions... plus i travel to south korea often and they were using a bull dozer there for demolition that said electric drive on it....First you have to be careful about marketing lables, they don't always mean what you think they do. Tesla has an "autopilot" but it doesn't mean you can plug in your destination, climb in the back and take a nap.

I did a quick check on the dozer. There is a diesel/electric Caterpillar dozer. From reading the materials, they are doing it for reasons similar to trains where the complexity of power transmission make it beneficial. Those aren't issues for low power displacement cruising boats. It's not an electric dozer but requires a constantly running diesel engine. The advantage is you can keep the engine running at optimal speed for efficiency.

I think a lot of folks are hung up on the batteries, the person i brought up who converted his boat to electric did not intend to run the electric motors off batteries alone. He bought a damaged boat for a fraction of the price with already damaged engines in the engine room from an unknown water leak situation. Both of the diesel engines were heavily damaged according to him and would need to be rebuilt due to sea water entering the internals of the engines. When he had a mechanic price him on rebuilding and bringing both of the drive motors back up to shape it was in the ballpark of 30-40k he told me. So he sat on the idea of buying the boat from the owner and haggled him down on the price heavily to make it worth his time, plus in his mind he said if he would have rebuilt the diesel drive motors that he would have had a fresh engine boat for less than some of the boats he looked at with already running engines in similar shape elsewhere outside of the engine room.

In regards to the batteries, he told me the old batteries that were in the engine room were unusable. So from the start he needed new batteries and 2 diesel engines to be rebuilt and if he was to keep them, the generator on the boat was already repaired previously by a mechanic with intentions to rebuild the main engines, so it was in good running order with fresh rebuild.

So after a lot of research he bought electric motors roughly equal in output to the diesel motors that where on the boat, he mentioned they were curtis motors with rated output of 190hp @144v each with controllers in a kit for 15k and he payed another 1k for the converter that converted the output voltage from the diesel generator he had so he could input the correct power from the generator directly to the electric motor circuit. So he disassembled the diesel engines in the engine room so they would be easier to remove and painfully had them removed from the boat, after removing those engines he had a local boat shop purchase them from him for 10k he mentioned.
The generator spec'd isn't going to be able to provide anything close to the rated power of the electric motors, even with a surge from the batteries. If you are simply going with a drastically smaller power package, the price comparison should be to smaller diesel motors and you will find they are significantly cheaper also.

After the diesel engines were removed, he repaired the engine room and had brackets made up to install the electric motor kits he purchased while he sourced batteries. He wanted to go lithium for more storage and range on the electric motors, plus double the use of them as house batteries to run the boat electrical system, so he won an auction on a totaled tesla model s for just under 8k and removed the battery modules from the tesla he purchased along with added a few extra modules over time he picked up from ebay for good prices. He said he rewired the boat so everything ran off the tesla battery bank.
Nothing wrong with doing it but if you compare prices of new vs junk yard parts, you aren't comparing apples to apples. New that tesla battery bank would be at least double or if you go out and find some functional but old diesel engines, you can get them for drastically less.

The intentions he said of the build was to run the boat off the voltage from the generator with the battery bank as a buffer, but he underestimated the amount of load he uses while cruising with the boat, so he is in the research phase of figuring out what to do with that side of the system. He has since added solar to the boat to trickle charge the batteries.
This is consistent with what people have been saying, electric motors are great if you have the electricity to feed them...but that's the main issue.

His ideas he brought up in our conversations was the possibilities of adding a 2nd generator to the boat with custom generator output of 144v, or upgrade his old generator to something larger and more efficient. He said if he adds a 2nd generator then he still has the ability to run the smaller generator for day to day use and use the new one mainly for driving the boat loads. He said there is so much more space in the engine room with those big diesel engines removed, that he could add a 2nd generator and even 2x or 3x his battery bank if he wanted to. A second large generator capable of feeding a pair of 190hp electric motors throws any cost savings out the window.

He told me he has less than 20k into his entire conversion from diesel drive to electric with the giant increase in battery storage with the tesla modules after taking out the money he got back from selling the old diesel engines. He also mentioned he has sold a handful of items off the tesla car to people for a few k along the way. His only reason for not increasing his battery bank is he said the prices of tesla's at the auctions has nearly doubled in price on totaled cars, with everyone wanting the batteries now the value of them has increased out of the range he is willing to pay for, but he keeps bidding on them with the hopes of scoring another for more modules.
Again, junkyard finances while fine for a DIY just muddy the waters when looking at the big picture of if they are viable. If you can ignore large cost components, the game changes but in terms of if you can make a viable off the shelf system, it needs to be kept clear of the discussions.

Also a correction, i thought he said it was 41ft, he said his boat is a 44ft defever, not 41.. that he purchased it for 27k

Nothing wrong if he wants to conduct an experiment that results in worse performance for no benefit. Most hobbies aren't profitable. It's when you ask if it's viable beyond the DIY hobbyist who doesn't care about performance loss or the financials, that it quickly falls apart.

[Dockhead]

Originally Posted by valhalla360

The electric motor powering the car is 150hp/275tq rating at 0rpms. Sorry but HP = torque * RPM, so if rpm = 0 HP = 0. The ratings are peak outputs (though for an electric motor, torque is pretty much consistent across the RPM range.

The gas engine onboard is 78hp/61tq rating at 6300rpms. The gas engine turns a 2nd electric motor rated at 55kw, to generate power for the drive electric motor to continue driving. When i am cruising here in Florida on I75, my gas engine rpms typically run just under 900rpms according to the display for me maintain a cruise control speed of 75MPH. Basically i have 275lbs of tq on tap to be used instead of the 61lbs of tq the gas engine puts out at 6300rpms. Again something isn't right. If the gas engine peaks at 61ft-lb assuming it is generating that at 900rpm (typically idle speed torque will be less), that calculates out to 10.5hp. Not a chance you are running 75mph on 10.5hp. Is it maybe getting most of the power from the battery with a supplement from the gas motor?

Got to wonder whether there is some basic misunderstanding of torque and horsepower here.

There is no free lunch -- power doesn't appear out of thin air -- when you convert mechanical power to electrical power and back to mechanical power. Work done is work done, and it's measured in kW/h or if you like, horsepower/hours. Horsepower, not torque, is the measure of work being done, and you can't conjure power out of the air by converting the form of it. On the contrary, something is always lost in each conversion. So if it takes 20 horsepower (say) to run a Chevy Volt down the highway at 75, then it will take more than 20 horsepower to run it down the highway at 75 with an electric motor being driven by a gas engine running a generator.

It is true that electric motors have different torque curves from I/C engines, and that is very useful for applications where you need torque to get a vehicle into motion or to accelerate (you don't need gears), but torque is not a measure of work being done, and if you want to get 20 horsepower at the wheels out of an electric motor, you will need for your gas engine to be producing 25hp or 28hp or whatever continuously unless you are taking power out of the battery bank.

[a64pilot]

The Volt however and the Prius, and I think pretty much all Hybrid automobiles have the ability to drive the wheels directly from the internal combustion engine or “ICE” as you will see it referred to in hybrid documents.
Rarely the Prius will drive the car electrically from electricity produced by the ICE, when it does this, it’s called the heretical mode, cause of course doing so when you can drive mechanically isn’t logical.
The only other time the Prius may drive the car electrically with electricity produced by the ICE is in reverse, if the battery is low, since it can’t directly drive the car in reverse.

I post this to try to illustrate that the hybrid cars go to great lengths when possible to not drive the car electrically with electric power produced from the ICE as that is inefficient, they will drive the wheels directly from the ICE whenever possible.

[a64pilot]

Another big reason why hybrid automobiles work is they enable the use of an Atkinson cycle engine, https://en.m.wikipedia.org/wiki/Atkinson_cycle
this engine has been around for more than 100 years but isn’t used in a regular automobile as it has a very poor ability to accelerate, low torque if you will.
However the electric motors will accelerate the vehicle nicely allowing the use of the Atkinson cycle engine. It’s the Atkinson cycle engine that gives good fuel economy at steady state highway speeds, not the hybrid system, that is largely dead weight at high, sustained speeds.
Newer cars have engines that emulate an Atkinson cycle and can operate as an Atkinson cycle at steady state and in the Otto cycle to accelerate. Different manufacturers have their own cute little names for it.

[Colin A]

The way the volt was explained to me the electric motors are always doing some work. Only if the battery gets to it's preset low threshold does the gas engine start. It then functions as a generator and depending on conditions it can also input some power thru a planetary gear but it's prime function is a generator. To the point thou the reason the did that clutched shaft to a planetary gear was they found it increased efficiency 10-15% to have the gas engine help the electric motor while the gas engine was running.

[Dockhead]

Originally Posted by Colin A

The way the volt was explained to me the electric motors are always doing some work. Only if the battery gets to it's preset low threshold does the gas engine start. It then functions as a generator and depending on conditions it can also input some power thru a planetary gear but it's prime function is a generator. To the point thou the reason the did that clutched shaft to a planetary gear was they found it increased efficiency 10-15% to have the gas engine help the electric motor while the gas engine was running.

Sure -- because delivering the mechanical power directly to the wheels is more efficient than converting it back and forth to and from electrical power. I'm sure they didn't "find" that -- as if it were a surprise. It's obvious, and the designers surely had it in mind all along.