Oceanvolt Hybrid Motor

[valhalla360]

Originally Posted by transmitterdan

A pure electric boat requires a massive solar array for anchoring out at remote idyllic harbors.

If one is concerned about making a carbon footprint one would never cruise in a boat. The tiny amount of fuel needed to maneuver a sailboat is minuscule compared to that used in the manufacturing process. Plus the fuel burned getting all the food, water and other supplies to whatever exotic destination you happen to be dwarfs any fuel the boat might have used to get there itself. Electric drive is not going to help the environment. Not to mention all the heavy metals and chemicals used to manufacture electric systems.

Certainly. I've had some old timers brag about using 5 gal of diesel per year.

You aren't going to save the planet or avoid insidious noise related diseases by spending many thousands replacing the little diesel engine with an electric motor and battery bank...if you make it a hybrid, you still have the diesel engine anyway.

[myocean]

Originally Posted by valhalla360

What you describe is a pure Battery Electric system with the ability to recharge using a hydro-generator when under sail.

Hydro-generation is a feature you can have for hybrid systems and in all-electric systems. Oceanvolt is the best example. The same is valid e.g. for Torqeedo.

[harlem24]

I think vallhalla wants to keep at least one diesel engine while OV and Torqueedo use diesel generators in their hybrid systems.
If I had the chance to do it, I think I would go the generator way.
Question might be how often you need the generator and if it's worth the higher complexity and high price. 20kW generators are between 15 and 20k.

[valhalla360]

Originally Posted by harlem24

I think vallhalla wants to keep at least one diesel engine while OV and Torqueedo use diesel generators in their hybrid systems.
If I had the chance to do it, I think I would go the generator way.
Question might be how often you need the generator and if it's worth the higher complexity and high price. 20kW generators are between 15 and 20k.

I'm just trying to clarify terminology.

An OV with a modest battery bank and diesel generator would be a hybrid system. Adding a hydro-generation would be an auxiliary charging source.

Now if you want an OV with generator, why? What are you gaining?

I can see the potential for a pure battery electric on a boat if you propulsion needs/expectations are very modest.

I can also see the potential for a standard diesel drivetrain.

What I don't see is the advantage of a hybrid drivetrain on a displacement cruising boat.

[harlem24]

The question is, how often would you need so much propulsion that you need the 20kW genset?
For manuovering the electric motors would be enough, for pushing you slowly through a calm they should also be good.
The only thing one needs is time.
If you are on a tight schedule electric propulsion is not for you.
I think that the hybrid option is the same as with cars, for people who want to go electric but don't trust it fully.

[transmitterdan]

There is no way one can reasonably compare hybrid cars and hybrid boats. A hybrid boat is not more efficient than a standard ICE+mechanical drive train. But a hybrid car is much more efficient than a standard ICE+mechanical drive system.

Hydro regen will rarely extract enough power from the sails to be a significant contributor to the overall energy budget of a cruising boat. Turning wind energy into hydro energy then into rotating mechanical energy and then into electricity is not efficient. There are losses at every step.

To make significant amounts of electricity you need huge solar arrays. And lots of sunlight.

[harlem24]

Hm, OV shows that it is possible to generate around 800W-1,5kW per motor from 6kn up.
On a cat you can generate I would suspect on an average sailing day with good wind about 13-18kWh (8h sailing).
That I would say is significant. Try that with a normal wind generator (300-400W).
And hydro works with every weather and around the clock.
On a passage with an average speed of 8kn, you would be able to generate 43kWh per day. That would be a luxurios crossing with no needs to compromise on energy.

[transmitterdan]

What happens when you stop and anchor for a few days?

[harlem24]

You need to have a battery and a solar system that matches the rest.
But here on the forum there are enough examples that those are no problem to be put in.
And if you ask people if they would rather have a genset or run the engine running or just spend the time quietly on anchor, you can imagine what the answer is...

[transmitterdan]

Exactly right. So this whole hydro regen nonsense is a red herring. It only works on passage plus it requires more work from the sails and rig. Since solar is required anyway why stress the boat to inefficiently make electricity? Regen does not turn a cat into a perpetual motion machine.

[harlem24]

No, but it might help and when you already have electric propulsion, why not use the benefit?
Sure nothing for weekenders, but hey...

[transmitterdan]

Originally Posted by harlem24

No, but it might help and when you already have electric propulsion, why not use the benefit?
Sure nothing for weekenders, but hey...

Because the first law of cruising says, “There is no free lunch.”

1) Regen puts more stress on the boat and rig.

1a) It requires over canvassing to power the hydro generation. So it leads to later rather than earlier reefing which we should all know is a bad idea.

2) Regen electronics are complex and more expensive. Try repairing a system in the South Pacific after accidental flooding.

3) Larger battery banks are needed to store the energy.

I’m not saying it doesn’t work at all. I’m simply saying it doesn’t pass the cost/benefit test on a cruising cat.

Weekenders probably benefit more
from an all electric boat than long distance cruisers. They can recharge from shore.

[yvest]

Originally Posted by transmitterdan

Because the first law of cruising says, “There is no free lunch.”

1) Regen puts more stress on the boat and rig.

1a) It requires over canvassing to power the hydro generation. So it leads to later rather than earlier reefing which we should all know is a bad idea.

2) Regen electronics are complex and more expensive. Try repairing a system in the South Pacific after accidental flooding.

3) Larger battery banks are needed to store the energy.

I’m not saying it doesn’t work at all. I’m simply saying it doesn’t pass the cost/benefit test on a cruising cat.

Weekenders probably benefit more
from an all electric boat than long distance cruisers. They can recharge from shore.

1) Don't think regen would put more stress on the boat and rig than a non folding propeller, which is "some", but ...

2) Not necessarily, an electric motor is inherently also a generator

3) key point is regen works at night or cloudy day on a passage, and if the batteries are full, you can heat your water for a shower or something

[transmitterdan]

Originally Posted by yvest

1) Don't think regen would put more stress on the boat and rig than a non folding propeller, which is "some", but ...

2) Not necessarily, an electric motor is inherently also a generator

3) key point is regen works at night or cloudy day on a passage, and if the batteries are full, you can heat your water for a shower or something

1) If the regen generates significant power that power has to come from sail, rig, boat and prop. This will certainly create more stress than a locked prop. But most cruising boats have folding or feathering props.

2) The electronics to feed/extract power to/from the motor are complex and incompatible with salt water. If the regen electronics fail then, in many systems, propulsion also fails as they share common elements to save cost and weight.

3) Yes, but what percentage of time do we spend on passage vs. lying at anchor? Regen cannot produce power at anchor. So an alternate form of reliable power generation is still needed for a cruising boat. Thus at least twice as many things to go wrong.

Given all the above what really is the point of regen for cruising besides “it’s cool”?

For racing it works but I suspect solar is better even for a racing yacht.

[yvest]

Originally Posted by transmitterdan

1) If the regen generates significant power that power has to come from sail, rig, boat and prop. This will certainly create more stress than a locked prop. But most cruising boats have folding or feathering props.

2) The electronics to feed/extract power to/from the motor are complex and incompatible with salt water. If the regen electronics fail then, in many systems, propulsion also fails as they share common elements to save cost and weight.

3) Yes, but what percentage of time do we spend on passage vs. lying at anchor? Regen cannot produce power at anchor. So an alternate form of reliable power generation is still needed for a cruising boat. Thus at least twice as many things to go wrong.

Given all the above what really is the point of regen for cruising besides “it’s cool”?

For racing it works but I suspect solar is better even for a racing yacht.

1) The regen power is on the order of 500 or 1kw, so around 1hp, again I don't think this point is major at all, and it can be stopped

2) I think OceanVolt, Torqeedo and others show that it can perfectly be done (not counting all the wind turbines and asscoiated electronics running for years, and for which the issues are more often mechanical than electronics)

3) Sure but on passage the loads can be higher : Autopilot, navigation electronics, nav lights added to the typical "house loads".

For me clearly having electric propulsion means it should be usable for regen, otherwise why bother ?

And hydro regen is a very efficient way to produce energy on passage, just consider all the watt&sea hydrogenerators on Vendée Globe boats or on cruising boats.