Oceanvolt Hybrid Motor

[tp12]

Originally Posted by tp12

Exactly. However, when you consider that he's shown video of actual numbers that Tony has achieved on Kato that people are saying is just marketing BS then my point is made for me.

So, he's just heading off at the pass what he's already had to deal with.

Not that it will work, mind you 😁

[transmitterdan]

Lower MOSFET on resistance might lower the cost but it won’t improve efficiency. A good 100kW PWM controller is about 97% efficient and has been for a long time.

Motors that are <90% efficient are only that way because of some design or cost constraint. It’s easy to find low loss motors. But they are not cheap nor do especially light. When the designer takes out half the copper and iron to reduce weight and cost the efficiency goes down. But no technology breakthrough is needed to have an efficient electric motor.

So it’s possible to have high efficiency but there’s no profit to be made in a market that is solely driven by lowest possible price. Look at all the people in this and other threads whining about the high cost of electric solutions.

[cwjohm]

Exactly. However, when you consider that he's shown video of actual numbers that Tony has achieved on Kato that people are saying is just marketing BS then my point is made for me.

So, he's just heading off at the pass what he's already had to deal with.

I think this is where this sort of discussion goes off the rails. Emotive red herrings that do nothing to add to the conversation.

In fact nobody has said that the actual numbers achieved on Kata is just marketing BS. Nobody has questioned the video.

What has been said is that the achievements of Kato (which everybody acknowledges is valid) do not demonstrate that a 15KW electric motor will generate the same performance as a 30KW diesel, or to put it another way if you put significantly less that a 30KW diesel on Kato it would generate the same performance.

All of this discussion of Kato proves that Tony and Julien have designed a bloody brilliant boat that you could probably use oars and it would still go at 10Kn. However, it goes no way to proving the basic assertions that 1 electric KW is equivalent to 2 diesel KW.

[tp12]

Originally Posted by cwjohm

I think this is where this sort of discussion goes off the rails. Emotive red herrings that do nothing to add to the conversation.

In fact nobody has said that the actual numbers achieved on Kata is just marketing BS. Nobody has questioned the video.

What has been said is that the achievements of Kato (which everybody acknowledges is valid) do not demonstrate that a 15KW electric motor will generate the same performance as a 30KW diesel, or to put it another way if you put significantly less that a 30KW diesel on Kato it would generate the same performance.

All of this discussion of Kato proves that Tony and Julien have designed a bloody brilliant boat that you could probably use oars and it would still go at 10Kn. However, it goes no way to proving the basic assertions that 1 electric KW is equivalent to 2 diesel KW.

Well that's just not true and, quite frankly, the thread was already off the rails by that rationale

[cwjohm]

I also predict that the data from these boats will comprehensively show that the "EP deniers" on this and other forums are, and have always been, totally wrong in their various statements that electric motors of a smaller kW continuous rating can deliver the same motoring results as a diesel somewhere between twice and three times the kW rating of the electric motor.

Rob, it may help if you toned down the language. Just because you believe in the laws of thermodynamics does not make you an "EP denier". None of us deny EP. Quite the contrary, most of us are well versed in EP for boats and believe it will come in time.

By your logic if I recommend a large diesel motor to someone because I do not think a smaller one will generate the performance I would rightly be classified as a "diesel denier". This is just plain silly.

Let us keep to the issue highlighted in the second part of your sentence above, which is all about the size of electric motor that is suitable to generate satisfactory performance, and leave the emotional stuff behind.

[StuM]

Interesting data posted in another thread today.

http://www.cruisersforum.com/forums/...ml#post2548620

Data from a Formosa 47 with EP (20kW QuietTorque). and 10kW generator.in calm conditions on a lake.

I suspect this is more illustrative of EP's potential than is Kato's performance for the majority of people here.

[cwjohm]

Well that's just not true and, quite frankly, the thread was already off the rails by that rationale

M: An argument is a connected series of statements intended to establish a proposition.
O: No it isn't!
M: Yes it is! 'tisn't just contradiction.
O: Look, if I *argue* with you, I must take up a contrary position!
M: Yes but it isn't just saying 'no it isn't'.
O: Yes it is! M: No it isn't!

Courtesy of Monty Python

[myocean]

Originally Posted by cwjohm

However, it goes no way to proving the basic assertions that 1 electric KW is equivalent to 2 diesel KW.

I agree in principle with what you said but still we should try to be more precise:
1. Depending on the working point an electric motor CAN be much more powerful (e.g. at low RPMs, where the combustion engine is very, very weak)! However at max power it is just max power and I don't think there is any additional magic unless you use very different props with different max RPMs.
2. A comparison with small outboard gasoline engines shows, that they are so bad and wrongly specified, that 1 kW electric is performing a lot better than a gasoline outboard with a similar specified power. (e.g when looking 1...5 hp outboards). So indeed a 1 kW electric motor can beat a 3 hp gasoline outboard in most disciplines (even though max speed is not always the best test for a high torque electric motor)
3. The very short response time of electric motors makes another difference in 'performance' which you feel when maneuvering a boat.

So, as I said, in principle you are right when looking at max. power/max. speed but 1 kW is not always 1 kW because torque curves and dynamics are just not the same.

[seandepagnier]

Originally Posted by transmitterdan

Lower MOSFET on resistance might lower the cost but it won’t improve efficiency. A good 100kW PWM controller is about 97% efficient and has been for a long time.

How does it not improve efficiency to have a lower on resistance with also a lower gate charge than what existed in previous years? Also, all the control electronics can use less power as well. Granted the improvement is slight, maybe we go from 97% to 98%

Motors that are <90% efficient are only that way because of some design or cost constraint. It’s easy to find low loss motors. But they are not cheap nor do especially light.

These motors are only efficient at specific speeds and loads, not over a wide range, and certainly not when driving a propeller in turbulent waters for example.

It's like saying the optimal boat hull design was known a long time ago, and is a canoe.

I'm just stating that there still is some room to improve electric motors, and as you say, efficiency is not the only factor, otherwise we would use silver wire in the motor.

[SV DestinyAscen]

Originally Posted by StuM

Interesting data posted in another thread today.

http://www.cruisersforum.com/forums/...ml#post2548620

Data from a Formosa 47 with EP (20kW QuietTorque). and 10kW generator.in calm conditions on a lake.

I suspect this is more illustrative of EP's potential than is Kato's performance for the majority of people here.

Reading thru this thread - what's becoming abundantly clear is there are people who are genuinely curious and interested, but it is really hard to sort thru the BS marketing.

It is like when electric cars were first being marketed, you couldn't get a straight answer re range and expected performance.

It isn't that hard to market a solid product. I'd want to know how much the battery/motor/any any required components weigh. I'd like to know what's the speed I can expect a given unit effectively provide propulsion equivalent to to the diesel that currently occupies that market, and for how long without extremely generous assumptions like mirror flat water and full battery charge after 2 weeks at sea.

Whenever claims are made about perpetual motion implications - hybrid generation, etc, I just tune it out.

[cwjohm]

I agree in principle with what you said but still we should try to be more precise:
1. Depending on the working point an electric motor CAN be much more powerful (e.g. at low RPMs, where the combustion engine is very, very weak)! However at max power it is just max power and I don't think there is any additional magic unless you use very different props with different max RPMs.
2. A comparison with small outboard gasoline engines shows, that they are so bad and wrongly specified, that 1 kW electric is performing a lot better than a gasoline outboard with a similar specified power. (e.g when looking 1...5 hp outboards). So indeed a 1 kW electric motor can beat a 3 hp gasoline outboard in most disciplines (even though max speed is not always the best test for a high torque electric motor)
3. The very short response time of electric motors makes another difference in 'performance' which you feel when maneuvering a boat.

So, as I said, in principle you are right when looking at max. power/max. speed but 1 kW is not always 1 kW because torque curves and dynamics are just not the same.

I agree with all of these points. That is why OceanVolt have made such inroads into small motors. However, it is a completely different story when comparing larger diesel motors driving larger boats where they are not badly specified, the torque curves are selected for normal performance criteria and maximum torque is needed for reasonable periods and from time to time.

[tp12]

Originally Posted by cwjohm

Rob, it may help if you toned down the language. Just because you believe in the laws of thermodynamics does not make you an "EP denier". None of us deny EP. Quite the contrary, most of us are well versed in EP for boats and believe it will come in time.

By your logic if I recommend a large diesel motor to someone because I do not think a smaller one will generate the performance I would rightly be classified as a "diesel denier". This is just plain silly.

Let us keep to the issue highlighted in the second part of your sentence above, which is all about the size of electric motor that is suitable to generate satisfactory performance, and leave the emotional stuff behind.

This is reductionist and dismissive. You've ascribed things to Bigbeakie that he simply hasn't done and are calling him out for emotively responding to people being dismissive, rude and sarcastic to him! Get a grip! Let's have some balance here.

It's clear that you can not have a worthwhile thread on this subject on this forum. I'll leave it at that.

[tp12]

Originally Posted by cwjohm

M: An argument is a connected series of statements intended to establish a proposition.
O: No it isn't!
M: Yes it is! 'tisn't just contradiction.
O: Look, if I *argue* with you, I must take up a contrary position!
M: Yes but it isn't just saying 'no it isn't'.
O: Yes it is! M: No it isn't!

Courtesy of Monty Python

You've clearly missed it in this thread where what I've said had already happened.

We're just going to have to agree to disagree and move on.

[StuM]

Originally Posted by SV DestinyAscen

It is like when electric cars were first being marketed, you couldn't get a straight answer re range and expected performance.

You talkin' about this:


or this:

[cwjohm]

It's clear that you can not have a worthwhile thread on this subject on this forum. I'll leave it at that.

Yes, I understand. Perhaps you could ask the moderators to allow you to start a thread on this subject, with the proviso that no dissenting opinions on the subject other that yours be allowed.