Triskel power generation system on Distant Shores III

[wingssail]

a64pilot,
Maybe you are so busy with the intense discussion you are having with other commentors you sort of missed my point:

A lot of boat owners/cruisers do not need or want a genset or a Triskel system. I think a large capacity alternator on the main engine is a good solution.

Originally Posted by a64pilot

Well a few things, first it’s said that the primary advantage of the system is to make tons of power when underway, but then you say no it’s got to be turned down.

No, I said that it is rare that a normal cruiser needs to make a lot of power underway, and I did not say it had to be turned down. I did, however, point out that an RPM influenced regulation would probably prevent a large alternator from overloading the engine.

But then you say save the 5KW of charging when your at anchor. I think it’s actually more than 5 but concede your point and that’s it’s a big boy generator at anchor. What are you going to charge with 5000W of power?

5000 Watts is way more than enough. I am happy with 2500wats. This is about 200amps and it reduces my daily charging time to 1 hour, more or less, assuming there was no motoring.

With that 2500watts I will recharge my 450Ah house battery bank in 1 hour. The solar's daily 60Ah is supplemental.

More likely people are going to run airconditioners and that’s going to really rack up hours on their engines.

If they want to run airconditioners they fall into the catagory of heavy power users. I don't see many cruisers who think they need to do this, but some do. They probably need gen-sets.

But we get to the crux of the issue really and that’s when underway you don’t get anything for your $20,000 that you don’t get with a big alternator for about 1/10 the money.

Yes.

And when your at anchor your using your prime mover as a generator adding hours to it. So your running your big motor at anchor to make electricity. Where is this 25% fuel savings?

So I’m trying to see how it’s going to save any fuel, especially when running a much larger than required engine when at anchor to make electricity, and when motoring your having to turn it’s output down.

Your can make a case for this Triskel, up until you get to the point of it costing $20,000. In my opinion.

Well, you obviously think I am in favor of Triskel. For most cruisers, I don't think it makes sense for cost reasons and the risk that it becomes hard to repair, replace, or support.

A cruiser often wears out an engine, that’s because they are cruising often 365 days a year. It’s the people that keep a boat in a marina and work that don’t wear out engines and due to them working they are part time cruisers at best.

But, Mr A64pilot, I stand by my main point, that some of us want to keep our boats simple, light fast, and avoid motoring. I've been cruising for 23 years and my motor is not worn out, so my own usage and experience shows that using the main engine does not nescessarily result in excess fuel costs or needless engine repairs or rebuilds. It does, however, result in alternator repair and replacement costs. Perhaps a gen set has similar ongoing costs.

So I say, stay light, stay simple, stay fast, have one engine on board and use it for everything.

[Q Xopa]

Originally Posted by rom

Where you stated that an alt cannot replace a genset (because it would not work for you I suppose). The simple fact that it works for me proves you wrong. To which may answer that it is not my alt that replaces a genset but my alt+solar, and you would be right. But anyway, since you ask, I am still not buying that "with a fixed prop it doesn't matter" theory and I am still waiting for a better development from you or dockhead. You could well be right, again.


Now, attached is my yanmar 4JH4E power curve. Max 40kW or 54hp. I find myself often motoring on one engine (the other prop is folded, FoF) at a bit less than 2000RPM on flat seas, no wind. How much power does it use ? I can't tell, but I am ready to bet it is less than half. Let's say half, 20kW. The curve says max ouput at 2000RPM is 32kW. Would I be right to say that it leaves a 12kW potential for adverse weather conditions OR a big alternator ? And BTW, where does overloading the engine starts ? is it 32kW or a bit below, way below ?Attachment 202579

Hmm, I cant remember saying that. Not that I am saying your wrong, just my memory is bad.

Oops, my bad, I must have not articulated myself very clearly because I certainly dont think that. Point in case Ive spent a good amount of time going down the large Alternator route myself, as I think I mentioned. I also said I prefer them over the gen, unless I cant find a good reason to run my motor. Ie at anchor, I think a cheap gen is better value.

But if I could only have one, I agree with you and ditch the Honda.

Fixed pitch props, I think you are asking A64? I have a Maxprop.

[a64pilot]

Originally Posted by wingssail

a64pilot,
Maybe you are so busy with the intense discussion you are having with other commentors you sort of missed my point:

A lot of boat owners/cruisers do not need or want a genset or a Triskel system. I think a large capacity alternator on the main engine is a good solution.

I agree, just I will sometimes sit for a week or so at anchor and that’s when for me a generator is pretty much required as my watermaker pulls a lot of current, more than my Solar could handle.
I’d prefer to run my generator as opposed to the propulsion motor.
But there are many ways to skin a Cat, as I’ve said big alternators are best utilized by people who most often motor, people who most often sail, or while at anchor, not so much.

[a64pilot]

Originally Posted by Q Xopa

Hmm, I cant remember saying that. Not that I am saying your wrong, just my memory is bad.

Oops, my bad, I must have not articulated myself very clearly because I certainly dont think that. Point in case Ive spent a good amount of time going down the large Alternator route myself, as I think I mentioned. I also said I prefer them over the gen, unless I cant find a good reason to run my motor. Ie at anchor, I think a cheap gen is better value.

But if I could only have one, I agree with you and ditch the Honda.

Fixed pitch props, I think you are asking A64? I have a Maxprop.

A Maxprop is a fixed pitch prop, yes it’s adjustable but not underway.

[Q Xopa]

Originally Posted by a64pilot

A Maxprop is a fixed pitch prop, yes it’s adjustable but not underway.

Yes you are correct

[wingssail]

Originally Posted by a64pilot

...as I’ve said big alternators are best utilized by people who most often motor, people who most often sail, or while at anchor, not so much...

Not exactly. People who most often sail usually have a boat which sails well and who want to sail as efficiently as possible. We don't like weight.

[noelex 77]

If setting up a boat for predominantly generator charging, it makes sense to make maximum utilisation of this resource.

Electric cooking instead of propane and low efficiency water-makers are just a couple of examples, but this philosophy extends to the selection of all equipment.

Unfortunately, this leaves the boat very dependent on the operation of the generator. Generators are not the most reliable pieces of equipment. If repairs are needed these often require specific parts and some expertise. This is not ideal when cruising long distances especially if this includes remote locations.

Larger cruising boats solve the problem by fitting two smaller generators.

It would seem to me one of the major appeals of the Triskel and similar systems that has not been mentioned, is fitting both the Triskel system and a diesel generator. The compact installation size make this viable for moderately sized yachts (say 50 feet). This enables them to take advantage of the redundancy previously only available to larger yachts, as well as choices regarding how the power is produced, that is not available with a two generator set up.

Personally I am more in favour of the simple, reliable solar set up, but this requires compromises that not everyone is prepared to live with. The Triskel system provides a worthwhile, although expensive alternative allowing generator equipped boats to install some worthwhile redundancy.

[Dockhead]

Originally Posted by noelex 77

If setting up a boat for predominantly generator charging, it makes sense to make maximum utilisation of this resource.

Electric cooking instead of propane and low efficiency water-makers are just a couple of examples, but this philosophy extends to the selection of all equipment.

Unfortunately, this leaves the boat very dependent on the operation of the generator. Generators are not the most reliable pieces of equipment. If repairs are needed these often require specific parts and some expertise. This is not ideal when cruising long distances especially if this includes remote locations.

Larger cruising boats solve the problem by fitting two smaller generators.

It would seem to me one of the major appeals of the Triskel and similar systems that has not been mentioned, is fitting both the Triskel system and a diesel generator. The compact installation size make this viable for moderately sized yachts (say 50 feet). This enables them to take advantage of the redundancy previously only available to larger yachts, as well as choices regarding how the power is produced, that is not available with a two generator set up.

Personally I am more in favour of the simple, reliable solar set up, but this requires compromises that not everyone is prepared to live with. The Triskel system provides a worthwhile, although expensive alternative allowing generator equipped boats to install some worthwhile redundancy.

No need for a $20k Triskell system to backup a separate generator. A large alternator combined with a good charger/inverter is just fine for this.


I can run my pretty electrical-intensive solar-less boat pretty well off the alternator, without any significant loss of functionality. Even charging time for my lead batteries is not longer with the alternator, compared to generator plus battery charger.


But of course it's nice to be able to bunch tasks together with your larger generator. Charge the batts while you're doing laundry or electric cooking or vacuuming or whatever. My 6.5kW generator is just about the right size for this -- 2.3kW or so for battery charging during bulk, leaving the full capacity of a good shore power connection plus some reserve.

[a64pilot]

Originally Posted by Dockhead

No need for a $20k Triskell system to backup a separate generator. A large alternator combined with a good charger/inverter is just fine for this.


I can run my pretty electrical-intensive solar-less boat pretty well off the alternator, without any significant loss of functionality. Even charging time for my lead batteries is not longer with the alternator, compared to generator plus battery charger.


But of course it's nice to be able to bunch tasks together with your larger generator. Charge the batts while you're doing laundry or electric cooking or vacuuming or whatever. My 6.5kW generator is just about the right size for this -- 2.3kW or so for battery charging during bulk, leaving the full capacity of a good shore power connection plus some reserve.

We can do the same with a 3.5, make water while washing clothes, Solar does most battery charging, actually we can and do, do that with a Honda, just you can’t heat water, make water and do anything else with a Honda, washing clothes takes very little power, but heating it and making it takes a good bit, so you do those separately or use a bigger generator.
I thought really ought to have redundancy assuming you go off the beaten path much, and even that beaten path may not have the parts availability you have become used to in Virginia or Florida etc. So to put all your electrical generation capacity in your propulsion engine is asking for trouble.
I can make water off of my alternator, and could easily charge batteries and do other things if I added a second or replaced it with a large frame. A lead acid battery bank will only accept 100 amps or more for a short time, but it takes hours to charge.
But we don’t try cooking electrically, even though many try to say it doesn’t take much electricity, I think it depends on how much and how often you cook, and what you define as cooking.

Actually I believe watermaker choice determines the need for a generator, that and of course the area and time of year you cruise.
No watermaker or maybe a spectra and be careful of how much water you use, and you have no need of a generator.

Air conditioning is what drives the requirement of a generator and you can either travel to a cooler clime, or say to heck with it, it’s Africa hot, we are taking a Marina until it’s not.

But average boat isn’t I don’t think a 50’ boat, and average boat can get by with a Honda, as long as they are not trying to run a clothes drier or something.

I keep getting back to the $20K part, yes I’m sure it’s a nice piece of kit, and I guess if you are spending millions on a boat it’s nothing.

But I think it’s a mistake to market it as a generator replacement for most anything except a power boat, but I believe it has to be marketed that way to get people of pay $20K. Look Hon, we buy this and we don’t have to have that big expensive heavy generator.
I say unless you willing to at least double and maybe triple the number of hours you put on you motor, maybe not.

The flip to that is if you only use it when your motoring, I bet you don’t need a generator at all, you could go with a big alternator or two.

[noelex 77]

Originally Posted by Dockhead

No need for a $20k Triskell system to backup a separate generator. A large alternator combined with a good charger/inverter is just fine for this.

A large frame alternator is a great source of power. It could be seen as a cheap Triskel system, but this is unfair as the alternator has some compelling advantages such as simplicity and ease of repair. In the event of trouble, a large frame alternator can even be completely replaced for reasonable cost.

However, the output is limited. For a new boat we installed a 170A @24v alternator. So theoretically 4kw, but I have limited this (via software) to arround 2Kw, which is think is a sensible amount for long term reliability. For a 12v boat this would need to be further reduced to around 1.5kw.

In our case, the alternator output is available to supplement solar production in areas of very poor solar isolation. We have not yet needed to use it in this role, but it should be a viable alternative. 2kw is healthy production rate for our boat, giving realistic run times even in the event of total failure of our solar installation (unlikely, as it is actually three independent systems).

For a modern boat designed for generator production especially with lithium batteries, I am not sure this is the case. Certainly with electric cooking, use of a washing machine, large watermaker and even limited running of air conditioning, the engine run times become unpleasantly long compared to the generator. I suspect many such boats would alter their planned cruising itinerary and divert for repair of the generator.

I have never used the Triskel system, but I understand around 7-8kw is available. With this much power a generator equipped boat could carry on with an unserviceable generator largely unaffected. The generator could be repaired at the next convenient location rather than altering plans. If the required repair parts were delayed (a not uncommon problem) there would be little need to spend the best parts of the cruising season stuck in port.

Whether this redundancy is worth the cost and increase in complication associated with the Triskel system is for the buyer to decide, but it does introduce a new option that for many boats has different practical implications than a large alternator.

[rom]

Originally Posted by noelex 77

For a new boat we installed a 170A @24v alternator. So theoretically 4kw, but I have limited this (via software) to arround 2Kw, which is think is a sensible amount for long term reliability. For a 12v boat this would need to be further reduced to around 1.5kw.

Buying a heavy duty alternator to run it at half its capacity sounds a bit strange to me... As for the Triskel I think it's a great system based on a great idea (using the space in between power & propeller curves). I wish there was a little more technical information on how they achieve that. Maybe that will come latter. I think a 24V version would make sense (delco says the 55SI@24V is 80% efficient, not bad !).

[noelex 77]

Originally Posted by rom

Buying a heavy duty alternator to run it at half its capacity sounds a bit strange to me..

The cost difference involved in buying a larger capacity industrial large frame alternator is small, especially for 24v. It is nothing like the increase in cost for small frame alternators that require sophisticated construction, cooling etc for a large current output.

The question is how much power can be reliably taken from the engine?

I think around 2kw from a single serpentine belt and a Yanmar 75hp is sensible amount, but this just an educated guess. Any other opinions would be welcome.

Importantly, in our case the 2kw output enables an electric kettle, or cooking to be run when motoring while still providing a slight positive charge to the batteries even without any solar contribution.

Meanwhile, the alternator itself (hopefully) remains reliable, running at around half its rated capacity.

This is easily adjustable via the alternator regulator so it can be adjusted back up to the full 4kw (or reduced below the 2kw) if this is deemed sensible. For my application, solar normally provides all the power we can use. The main engine is run little so the alternator contribution is always going to be small. Reliability of the system and the main engine in particular, is a more important criterion so I would rather err on the conservative side.

[Fuss]

Originally Posted by Dockhead

No need for a $20k Triskell system to backup a separate generator. A large alternator combined with a good charger/inverter is just fine for this.


I can run my pretty electrical-intensive solar-less boat pretty well off the alternator, without any significant loss of functionality. Even charging time for my lead batteries is not longer with the alternator, compared to generator plus battery charger.


But of course it's nice to be able to bunch tasks together with your larger generator. Charge the batts while you're doing laundry or electric cooking or vacuuming or whatever. My 6.5kW generator is just about the right size for this -- 2.3kW or so for battery charging during bulk, leaving the full capacity of a good shore power connection plus some reserve.

My view too, I understand that not having a generator is nice, but I like having a generator even though I don't use it much as I have some solar too.

But lets compare the Triskell system to mine as I do not see the benefit.
First lets not bring my generator or solar into the equation and lets just compare the Triskell.
I have a 135hp 6 cylinder with 3 24v alternators 110ah and 55ah running off the front pulley and 70ah running off the propshaft all contributing to a 650ah battery bank if I run the engine.
If I am sailing then only the propshaft alternator contributes.

I don't see how the Triskell improves on this.

If mine breaks, It has some redundancy.

[rom]

Originally Posted by noelex 77

I think around 2kw from a single serpentine belt and a Yanmar 75hp is sensible amount, but this just an educated guess. Any other opinions would be welcome.

Triskel... 8kW on a lagoon 46 engine which I believe is Yanmar 4JH57.
Also https://www.integrelmarine.com/integ...-penta-france/ , that is for engines starting at 50hp.

[noelex 77]

Originally Posted by rom

Triskel... 8kW on a lagoon 46 engine which I believe is Yanmar 4JH57.
Also https://www.integrelmarine.com/integ...-penta-france/ , that is for engines starting at 50hp.

The 8kw does provide a useful data point, but the Triskel system is not the same as a large alternator.

The details of the Triskel system are sketchy, but it uses engine management monitoring and automatic power adjustment to hopefully eliminate some of the engine overloading problems that would otherwise occur. A64 has outlined these problems in his posts on this thread.

These are real concerns. I have heard about a number of engines damaged from misuse of the overdrive feature of the Gori prop. I think similar problems would occur if you tried to extract 8kw of electrical power (of course with alternator inefficiencies this will require considerably more mechanical power) without these management protections.

You could install an EGT guage, and this together with some common sense this could be used to modulate the alternator field current manually, but most yachts don’t have this level of sophistication or these safeguards.

The second problem is extracting 8+kw via a belt from the main engine crankshaft, especially via a pulley mounted a long way forward, as most alternator aftermarket conversion kits do. Once again you need a managment system with soft start and ramp up to control the torque with variable demands. Some means of reducing the side loading is needed or at least some engineering calculations to check the load is acceptable for that particular engine. In practice, I suspect the only reliable DIY approach to generate this type of power would be from the prop-shaft or lay shaft suitably supported.

I have no doubt 8kw of electrical power can be generated from the main engine at least in many circumstances, but the question remains of how much power can be reliably generated from a more simple aftermarket large frame alternator conversion? Perhaps my 2kw is too conservative.