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Old 30-10-2016, 09:15   #181
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Re: Oceanvolt Hybrid Motor

After listening to the many arguments why hybrid power isn't suited for a cruising cat, I think I may have thought of a hybrid setup that might check all boxes. Before explaining, I will concede that it is more complicated, so that would be an obvious negative that would have to be de-bugged like all new systems. But here it is:

Someone mentioned that the way diesel electric submarines work is ideal because they place the electric motors on the same shaft as the diesel to allow clutches to shift between, electric, diesel, and power generation operation. I propose the same concept except using a saildrive where the electric motor is place on top, shaft pointing down (there is still a diesel turning the shaft from the side), and clutches between all shafts (prop, electric, and diesel). This saildrive package would allow, full diesel propulsion, full electric propulsion, a blend of propulsion power, full diesel power generation, or full hydroelectric power generation, all depending on changing needs. You use a larger than standard diesel on one side and only an electric motor/saildrive (no diesel) combo on the opposite side.

Benefits:
-electric motors work better with slightly larger props, which is fine since the single diesel is oversized
-full electric whenever desired (symmetrical electric power delivery for docking)
-Normal diesel cursing range since max ranges are already achieved using only one engine
-Good emergency power since, in an emergency, you could redline an oversized diesel as well as send all available battery power to the single opposing electric motor (not quite as good as 2 diesels, but should get it done for short periods of time)
-All the other benefits of electric sailing (regeneration from sailing and solar out to about a 40 mile range with no use of diesel etc.)
-Comparable weight since you are eliminating a gen set and one diesel and adding a two light electric motors and some batteries.

Throw an extra LiPo battery bank where the other diesel used to sit and it seems to check all boxes. Let's hear what the skeptics have to say...
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Old 30-10-2016, 10:04   #182
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Re: Oceanvolt Hybrid Motor

SD,

Don't you just love spell check.

"Normal diesel cursing range since max ranges are already achieved using only one engine"

I imagine some boaters normally curse their diesels.

Thanks for my morning chuckle.

BTW yours sounds like an intriguing idea but who's gonna make that clutched up sail drive. Sounds expensive, as if they aren't already.
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Old 30-10-2016, 10:39   #183
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Re: Oceanvolt Hybrid Motor

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Originally Posted by SDChristian View Post
After listening to the many arguments why hybrid power isn't suited for a cruising cat, I think I may have thought of a hybrid setup that might check all boxes. Before explaining, I will concede that it is more complicated, so that would be an obvious negative that would have to be de-bugged like all new systems. But here it is:

Someone mentioned that the way diesel electric submarines work is ideal because they place the electric motors on the same shaft as the diesel to allow clutches to shift between, electric, diesel, and power generation operation. I propose the same concept except using a saildrive where the electric motor is place on top, shaft pointing down (there is still a diesel turning the shaft from the side), and clutches between all shafts (prop, electric, and diesel). This saildrive package would allow, full diesel propulsion, full electric propulsion, a blend of propulsion power, full diesel power generation, or full hydroelectric power generation, all depending on changing needs. You use a larger than standard diesel on one side and only an electric motor/saildrive (no diesel) combo on the opposite side.

Benefits:
-electric motors work better with slightly larger props, which is fine since the single diesel is oversized
-full electric whenever desired (symmetrical electric power delivery for docking)
-Normal diesel cursing range since max ranges are already achieved using only one engine
-Good emergency power since, in an emergency, you could redline an oversized diesel as well as send all available battery power to the single opposing electric motor (not quite as good as 2 diesels, but should get it done for short periods of time)
-All the other benefits of electric sailing (regeneration from sailing and solar out to about a 40 mile range with no use of diesel etc.)
-Comparable weight since you are eliminating a gen set and one diesel and adding a two light electric motors and some batteries.

Throw an extra LiPo battery bank where the other diesel used to sit and it seems to check all boxes. Let's hear what the skeptics have to say...
Have you seen the Nanni hybrid system?

http://www.nannidiesel.co.nz/Products/view/96

They have since introduced a 15kW system as well.

- Fabian
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Old 30-10-2016, 10:45   #184
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Re: Oceanvolt Hybrid Motor

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Originally Posted by nuccifilms View Post
i got some advice that could help you (or hurt you, if you don't know what you're doing) 48vdc to 12vdc hasn't the common market demand for you to find much bigger wattages. however, these 360 watt dc to dc step down transformers you might find on those electronic importers sites are very cheap. you could do a couple things:



1) put a transformer for each load. you probably don't have anything drawing more than 360 watts. and you could use smaller transformers for some of your smaller 12v loads, like LED lighting.



2) you could buy several transformers, with the same exact same rating, and wire them in parallel. you can only get away with this with identical transformers (having identical impedance) as a safe guard you would wire in a separate fuse on the positive wire of each of your transformers, and also wire in a rectifying bridge for good measure.



3) you could have 2 separate battery banks (because more battery storage is not a bad thing) however, instead of 2 generators, you could wire in an A/B switch on your one generator. have that switch conveniently mounted on your console next to your battery level indicators. then you'd simply jump back and forth according to the levels of your 2 battery banks. keep in mind, you'd still end up using a step down transformer on the charging current going to your 12v batter bank, because your 12v batteries and anything on that circuit wouldn't like getting 48V. AND your generator is most likely pushing more than 360 watts, so you'd be employing the method of #2 suggestion in this system as well



4) 2 completely independent 12vdc and 48vdc systems, as was suggested to you



i'm the mad scientist that would go with #2 for it being the most robust. i'd also rule out suggestion #3 and #4 for those just having too many extra wires and stuff on your boat, and more stuff means more to go wrong. but i do think i covered all possibilities. maybe a 5th is to have an electronics engineer make you a custom several kw step down transformer, but custom will seriously cost.

No such thing as a DC transformer.
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Old 30-10-2016, 10:56   #185
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Re: Oceanvolt Hybrid Motor

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Originally Posted by Cap Erict3 View Post
No such thing as a DC transformer.


Actually there is. Some may call them DC-DC converters but they perform the same function as a transformer. They convert one DC voltage to another voltage. They are very efficient at up to 95% which is about the same as AC transformers used on boats.
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Old 30-10-2016, 11:05   #186
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Re: Oceanvolt Hybrid Motor

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Originally Posted by fabgo View Post
Have you seen the Nanni hybrid system?

Nanni Diesel

They have since introduced a 15kW system as well.

- Fabian
I had not! So this system with a matching electric only on the opposing side might be just the ticket?
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Old 30-10-2016, 11:23   #187
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Re: Oceanvolt Hybrid Motor

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Originally Posted by transmitterdan View Post
Actually there is. Some may call them DC-DC converters but they perform the same function as a transformer. They convert one DC voltage to another voltage. They are very efficient at up to 95% which is about the same as AC transformers used on boats.

But a converter is an electronic device while a transformer is ferrous metal and wire.
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Old 30-10-2016, 12:16   #188
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Re: Oceanvolt Hybrid Motor

picking on semantics doesn't change any points or solutions i've made. my list was pretty thorough, and designed to help.

as for the thread electric/diesel debate, here's some sobering facts. pound for pound diesel is more energy dense than lithiums (about 18 times) we won't be reaching the moon anytime soon on lithium. however, there is another major factor that chops down that disparity. the electric motor itself is 3 times more efficient than combustion. combustion has tons of it's kinetic energy expelled as heat out of the exhaust and through it's water cooling system. divide 18 by 3 and you still have diesel system winning by (6 times) more efficient (overall) than electric. one is quiet, clean and less maintenance, and the other (currently) better meets the demands of an energy hog vessel.
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Old 30-10-2016, 15:35   #189
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Re: Oceanvolt Hybrid Motor

Quote:
Originally Posted by myocean View Post
Look for example at the Volvo D2-40 datasheet
( http://www.volspec.co.uk/engines/mar...0_epatier3.pdf , dashed line in first diagram on right hand side ).
You see that at 1600 rpm with the recommended prop, the calculated propellor load (shaft power) is about 3.5 kW. So if both Volvo D2-40 engines run with 1600 and the boat makes 7 knots with this, than the "7 at 7" claim is correct.

As it might be possible to operate an electric motor at even lower rpms with higher torque (with larger prop diameter), there could be some additional gain in hydrodynamic efficiency. But this is not mandatory.
I doubt that many 45-50' cruising cats would make anywhere near 7 knots on those engines at 1600 RPM. More like 22-2400 RPM in my experience
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Old 30-10-2016, 17:03   #190
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Re: Oceanvolt Hybrid Motor

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Originally Posted by ejlindahl View Post
SD,

Don't you just love spell check.

"Normal diesel cursing range since max ranges are already achieved using only one engine"

I imagine some boaters normally curse their diesels.

Thanks for my morning chuckle.

BTW yours sounds like an intriguing idea but who's gonna make that clutched up sail drive. Sounds expensive, as if they aren't already.
Auto-correct has made me from a person who can't spell, into a person who can't spell or use the right words! And it looks like Nanni Diesel already makes the saildrive unit that I describe (but better and more simple).
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Old 30-10-2016, 17:10   #191
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Re: Oceanvolt Hybrid Motor

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Originally Posted by StuM View Post
Please learn the difference between power and energy before opining on motors. That should be kW - a measure of Power. KWh is an entirely different thing - it's a measure of energy. You can't convert kWh to HP, they are totally different units.

And that 8 HP to 6.8HP only tells us at how inefficient the system is converting the output of the diesel engine to electricity, It tells us nothing about how efficient the diesel engine itself is at converting diesel to usable energy.
(Your claim was "While a generator may be 90% efficient at converting diesel to energy")
You nitpick,yet the funny thing is,I took a minute and looked back on a few of your posts and you type "Hp".
Not HP/h like it ought to be.

At any rate,at the end of the day and despite protests to the contrary,diesel electric is nowhere near as efficient as a plain transmission.
If you want to run a DE system to get out of port,charge the large weight of batteries on solar (good luck) to run in and out of ports or the canals of Europe-good for you. Just don't claim you get better mpg.

And all this about electric making more torque to turn a larger prop slower and gain efficiency=BS.
If you want the same Hp and more torque from a diesel an electric motor,all you need to to is run a slightly lower gear ratio in the (~97%) efficient transmission...speed will drop and torque will rise.
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Old 30-10-2016, 18:19   #192
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Re: Oceanvolt Hybrid Motor

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Originally Posted by DaveWalters View Post
You nitpick,yet the funny thing is,I took a minute and looked back on a few of your posts and you type "Hp".
Not HP/h like it ought to be.

WTF? HP/h is almost totally meaningless -about the only place it could possibly make sense would be talking about the rate at which you are moving your throttle lever !
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Old 30-10-2016, 21:02   #193
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Re: Oceanvolt Hybrid Motor

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WTF? HP/h is almost totally meaningless -about the only place it could possibly make sense would be talking about the rate at which you are moving your throttle lever !
Technically that is how it is measured.
Just like the kW vs kWh you are nitpicking about.

On that topic,seeing as you are so uptight about nomenclature you ought to notify Cummins and tell them they are doing it wrong:

You are being redirected...

Yanmar too:

https://www.yanmar.com/global/genera...el_generators/

And virtually every generator dealer out there:
7-33 kW Diesel - Hardy Diesel's & Equipment Inc * Diesel Generators

I don't see any "h" after the kW, better get on that.
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Old 30-10-2016, 21:44   #194
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Re: Oceanvolt Hybrid Motor

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Originally Posted by myocean View Post
This is the cruisers forum and from my point of view cruisers do not motor a lot.
People go in and out of the anchorage and may motor one more hours here and there.
With a good hybrid system on a cat, you can get power from hydrogeneration and use this later on for motoring. Depending on the boat and the system you can get power for 4 hours of motoring with 4 knots out of 6-8 hours of sailing with 8 knots. (and you have solar power on top of that). This is very nice for regular use!
At the same time the long range motoring is not what cruisers do every day. But still the long range motoring efficiency of a good hybrid system is very good! It will not cause much more diesel consumption in comparison. May be 5%, depending of what configurations you compare and at what speed.
Care to share market stats to support this.

Coastal cruising the numbers that get thrown around are in the 80-95% of miles are under power.

Even ocean crossing most cruisers talk about day or more time periods under power to keep going in calm conditions.

If what you said was true, you'd see 45-50' cats with a pair of 5-10hp diesels to save cost and weight because all they are needed for is occasional use to get in and out of marina/anchorage.

As previously stated, if you don't want a viable motoring system for normal cruising, sure you can get away with a substandard system.
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Old 30-10-2016, 21:47   #195
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Re: Oceanvolt Hybrid Motor

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Originally Posted by myocean View Post
Look for example at the Volvo D2-40 datasheet
( http://www.volspec.co.uk/engines/mar...0_epatier3.pdf , dashed line in first diagram on right hand side ).
You see that at 1600 rpm with the recommended prop, the calculated propellor load (shaft power) is about 3.5 kW. So if both Volvo D2-40 engines run with 1600 and the boat makes 7 knots with this, than the "7 at 7" claim is correct.

As it might be possible to operate an electric motor at even lower rpms with higher torque (with larger prop diameter), there could be some additional gain in hydrodynamic efficiency. But this is not mandatory.
Again, pieces and parts but not a whole cruising boat design. Put that in a 1 ton ultra lightweight boat that is totally impractical for cruising and you can probably hit the 7 at 7. Put it in a real boat and it's a different ballgame. This is why you see advertising claims where they leave out a lot of detil.
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