Oceanvolt Hybrid Motor

[44'cruisingcat]

Originally Posted by myocean

Torqeedo is currently equipping a new Privilege 5 catamaran with a Deep Blue system with twin 50 kW motors. They will provide an enormous power and are still not much heavier than a smaller motor: 88 kg each.

50 kW from an 88 kg motor sounds great. Unfortunately, the two 50 kW motors at 88 kg each will not be able to provide any power, unless they're connected to a large generator or battery bank.

When looking at the weight of engines, you do really need to look at the entire system.

Similarly, when looking at potential fuel savings, it would make sense to compare the initial cost of the entire system.

[Claude-D]

Originally Posted by 44'cruisingcat

No accusations, simply stating facts. You might try it some time. They do say a change is as good as a holiday!

As for your other garbage, we motored into 35-40 knots with ease, as far as the engines were concerned. As I said, we backed off because of how rough it was. I have no doubt we could have easily maintained steerage way into a steady 40. We weren't thousands of miles out to sea, but about 20. If you're thousands of miles out there wouldn't be much point motoring into 40 kts, would there? It wasn't for long, but a few hours.

I really don't care if you believe that or not. I've seen you doing your sales pitch for Torqueedo, so I know about your credibility.

So, remind me what these facts are again? Stating fact is saying something like "This boat can do 6.5knots using 6.7kW from its batteries and genset" or "From 3.6kW output from the genset, this boat can do 4.3knots in calm conditions." A fact is not to say "this boat can only continuously do 4 knots" leaving the reader to believe that the boat is equipped with the same style of installation as Rob is planning. This is deceiving by omission...

Yes, I will choose to believe what I want to believe about your motoring against 35knots of wind. But before you come up with some facts about this I will believe the same as would anyone who has been at sea in a bit of wind (meaning over 35knots).

You can be insulting as much as you want about Torqeedo. And I know that even if you were on board at the time and you had experienced the boat doing 6.5knots with a twin Cruise motor installation, you would still deny it to make yourself feel better.

[ranchero76]

I gave up participating in such discussions on this forum - it's simply wrong place. But for these who might be interested, I can share my thoughts after two years reading and researching. Surprisingly, my conclusions are the same as Hugh Howey made in his last post in St.Francis 50 thread.

Best setup for now - diesel in one hull, and powerful (50-70kW) modern small electric motor in other hull, along with 50kWh batteries and 5-8kW solar.

1. Most cruisers only using one engine while motoring, so there will be one when long motoring needed and there's not enough energy in batteries and not enough sun.
2. For all other cases, except #1, there will be luxury silent motoring, using as little power as possible. Most opponents get "blinded" by that maximum power number. That maximum (50-70kW) only will be used for short time in emergency situations, when someone will need equal power in both hulls.
Numbers from Kato 2000 give an idea how little power can move such boat.
3. Big battery bank and big solar array will be used either to power electric propulsion or (when anchored) powering all power devices on boat, including power hungry ones (AC, dehumidifiers, water maker, etc.)
4. Hugh Howey: "When I'm sailing along, and the batteries are at 100%, all the energy hitting the solar panels is lost. You could put the electric motor in gear and gain a knot for free. On long passages, this can really make a difference. Or you can move on and off anchor without cranking a noisy engine. The times you need two screws for maneuvering, you've got both."

[myocean]

Originally Posted by 44'cruisingcat

50 kW from an 88 kg motor sounds great. Unfortunately, the two 50 kW motors at 88 kg each will not be able to provide any power, unless they're connected to a large generator or battery bank.

Yes, absolutely. But if you anyway go for a hybrid electric system, choosing a bigger motor which provides a bit more safety margin in dangerous situations, does not come with a lot more weight. That's what I wanted to say.

[ranchero76]

Regarding the weight - 58hp electric motor with 92% max efficiency - 22.7kg. Of course, this is by far not the best motor on the market, just one example. $3120.
Curtis 1238-7601 HPEVS AC-15 Brushless AC Motor Kit - 96 Volt, EV West - Electric Vehicle Parts, Components, EVSE Charging Stations, Electric Car Conversion Kits

[myocean]

Originally Posted by ranchero76

Regarding the weight - 58hp electric motor with 92% max efficiency - 22.7kg.

Lets talk about real kW, not unspecified hp please. The "conversion factor" is the same for all electric motors. The question is only how the manufacturer chooses to define it.
The Torqeedo motor you are comparing with includes all the mechanics around needed for a proper installation, the sea water cooling system, the power electronics and so on - all IP67 water resistant. The motor element alone would be 40-50 kg and provides a continuous shaft power of something like 53 kW and a peak power of 66 kW.

[DotDun]

Originally Posted by BigBeakie

We would never be motoring into 40 knots winds continuously, as there are much better options for a sailboat for that scenario. Our boat is designed as a bluewater boat with a heavy duty, reefing staysail (Cutter rig) and deep third reefed main. So another posters question about how fast and how long we could motor into a 40 knot wind is irrelevant for us.

Might be good option for middle of the ocean, but not during a 3 hour thunderstorm just off a lee shore. Believe me, in 40-50kt winds and the 15' steep short interval waves they cause, the last thing you want to do is deploy a sail. Motoring into the wind and keep the bow pointed into the waves is all that is on your mind.

You should try it sometime!

[ranchero76]

Originally Posted by myocean

Lets talk about real kW, not unspecified hp please. The "conversion factor" is the same for all electric motors. The question is only how the manufacturer chooses to define it.
The Torqeedo motor you are comparing with includes all the mechanics around needed for a proper installation, the sea water cooling system, the power electronics and so on - all IP67 water resistant. The motor element alone would be 40-50 kg and provides a continuous shaft power of something like 53 kW and a peak power of 66 kW.

The 1hp=0.736kW, power IS specified in specs (link provided above) it is rated power. There are few dozens of other motors on that site to choose from, this was just single example.
I didn't compare anything to anything, I've provided info about one particular motor, and mentioned that there are thousands other modern small powerful motors to choose from out there.
Installation of such system should be done by engineer, who can design cooling and splash protection as needed, so IP67 is not necessary.
At 92-94% efficiency no huge cooling systems needed, especially keeping in mind it never will run at high power for extended period of time - even with 50kWh battery bank at 50kW it's only 1hr run max.
also I didn't tell there will be no other bolts or nuts required for installation.
What's clear - that any existing "all included" marine electric propulsion systems are overpriced to the point that only people with extremely deep pockets might even potentially think about installing them.
On other side, there are talented people who can create magic for pennies, these are the best to learn from.

[rom]

Originally Posted by 44'cruisingcat

50 kW from an 88 kg motor sounds great.

It doesn't seem so good to me considering Tesla's 270kW motor (motor alone) weights 32 kg !

https://www.youtube.com/watch?v=3SAxXUIre28

[ranchero76]

Yeah, I forgot to include that example . Tesla motor has been hacked long time ago, and can be used with third party controllers/drivers in any application. Cost? One crashed Tesla. Motor and any required components can be taken out, the rest sold quickly for profit. So, motor price will be negative .

[myocean]

Originally Posted by ranchero76

I've provided info about one particular motor, and mentioned that there are thousands other modern small powerful motors to choose from out there.

There are certainly many possible setups around. I would personally recommend to look a bit more into the details.
Water resistance helps for longevity which is why professional marine equipment companies provide this feature. With this, cooling becomes a separate task and the 92% efficiency (Torqeedo: 96%) account for 3.5 kW of excess heat you need to get out of the motor.
Further one should look at the RPMs. The motor you mentioned comes without any transmission and works with more than 4000 rpm. Could a simple solution be a strong belt drive - I don't know. Other motors come with an integrated, maintenance free planetary drive which provides exactly the prop rpm needed or they are direct drives without transmission at all (heavier but extremely durable).
Next is the inverter which needs to come with a decent vector control electronics - because only with this you will be able to really operate the motor with a good efficiency at different working points. By the way the encoder needed for this might suffer from a non-marine grade packaging and cause trouble very soon.

[myocean]

Originally Posted by rom

It doesn't seem so good to me considering Tesla's 270kW motor (motor alone) weights 32 kg !

Oh yes, one more thing to keep in mind: Beside the rpm - if you read about the power of an electric motor always check if this is a peak power available for a few seconds or really a continuous power, which is what you need for boating use. I have not yet found this number for the Tesla motors.
Efficiency: The Tesla I have been looking at has a efficiency of 91% at 50 kW and 85% at peak power (up to 9000 rpm )
There are sooo many factors differentiating all the various electric motor, that it is not trivial to find the right one for little money which is really good for usage in a boat.

[44'cruisingcat]

Originally Posted by Claude-D

So, remind me what these facts are again? Stating fact is saying something like "This boat can do 6.5knots using 6.7kW from its batteries and genset" or "From 3.6kW output from the genset, this boat can do 4.3knots in calm conditions." A fact is not to say "this boat can only continuously do 4 knots" leaving the reader to believe that the boat is equipped with the same style of installation as Rob is planning. This is deceiving by omission...

Yes, I will choose to believe what I want to believe about your motoring against 35knots of wind. But before you come up with some facts about this I will believe the same as would anyone who has been at sea in a bit of wind (meaning over 35knots).

You can be insulting as much as you want about Torqeedo. And I know that even if you were on board at the time and you had experienced the boat doing 6.5knots with a twin Cruise motor installation, you would still deny it to make yourself feel better.

Yes, I've only done a few miles in the past seven years full time cruising. And never been at sea in a bit of wind.

As for the 6.5 kts..... motoring south next to Urangan pier with an incoming tide..... sound familiar? Exactly how strong was that tide? And how good was that reverse thrust pulling up at the marina? Wonder if you tell customers about that? How about here on the forum?

[44'cruisingcat]

Originally Posted by DotDun

Might be good option for middle of the ocean, but not during a 3 hour thunderstorm just off a lee shore. Believe me, in 40-50kt winds and the 15' steep short interval waves they cause, the last thing you want to do is deploy a sail. Motoring into the wind and keep the bow pointed into the waves is all that is on your mind.

You should try it sometime!

Reality vs theory.

[Stumble]

Originally Posted by ranchero76

I gave up participating in such discussions on this forum - it's simply wrong place. But for these who might be interested, I can share my thoughts after two years reading and researching. Surprisingly, my conclusions are the same as Hugh Howey made in his last post in St.Francis 50 thread.

Best setup for now - diesel in one hull, and powerful (50-70kW) modern small electric motor in other hull, along with 50kWh batteries and 5-8kW solar.

1. Most cruisers only using one engine while motoring, so there will be one when long motoring needed and there's not enough energy in batteries and not enough sun.
2. For all other cases, except #1, there will be luxury silent motoring, using as little power as possible. Most opponents get "blinded" by that maximum power number. That maximum (50-70kW) only will be used for short time in emergency situations, when someone will need equal power in both hulls.
Numbers from Kato 2000 give an idea how little power can move such boat.
3. Big battery bank and big solar array will be used either to power electric propulsion or (when anchored) powering all power devices on boat, including power hungry ones (AC, dehumidifiers, water maker, etc.)
4. Hugh Howey: "When I'm sailing along, and the batteries are at 100%, all the energy hitting the solar panels is lost. You could put the electric motor in gear and gain a knot for free. On long passages, this can really make a difference. Or you can move on and off anchor without cranking a noisy engine. The times you need two screws for maneuvering, you've got both."

The problem with this set up is the massive throttle response difference in close quarter maneuvering. It will take a lot of time and experience getting used to this system to operate it safely in close quarters because of this. Doable of course, but a serious learning curve.

By preference I would rather two electric drives and two DC generators. One generator sized for normal house loads and one sized for propulsion. Sized so that when they are both turned on you can meet peek motor demand. So if you have twin 20kw motors, you would use a 10kw and a 30kw generator.


But frankly I still think electric propulsion for a cruising boat is still silly. The cost and trade offs just don't make sense to me right now. For a day sailor however they are ideal.