Swapping from red diesel to HVO fuel

[Tony Brooks]

I am afraid the above from Peter seems to prove very little apart from the Lynch system can be configured to produce high powers and thus speed for what reads very like short term "sprint" type uses. That is what I would expect from a brushed DC motor that should give maximum torque and thus devoir maximum current at zero revs. Load it up and pull the revs down the currant rises.

 

I also detect a degree of marketing "information" in there, specifically the talk about what I call face armatures that can be found in many starter motors nowadays.

 

For inland marine use I see the need is for adequate power that can be delivered for long enough in bad conditions like high water flows. The "for long enough" is a function of battery capacity plus current flow. I think the current flow bit is where the "dispute" is. Peter seems to say the Lynch system is good enough for my and my friend's use. Ian seems to say that permanent magnet motors use less electricity for a given power output. That is all exactly as I expect.

 

I think Ian's permanent magnet motors are essentially turned inside out with the permanent magnets being the spinning element and the coils fixed around the outside. That type of motor must be better cooled than one with spinning coils, especially if it is fan or water cooled like alternators.

 

Both will do the job but one, it seems, will do the same job with  smaller and thus cheaper batteries. The other aspect seems to be the cost and efficiency of the control gear and so far I have not noticed Peter giving a comparative cost of the Lynch system that can be directly compared with Ian's. The efficiency of the control gear is important because of the need to deal with waste heat and the amount of electricity such heat wastes, that comes back to battery capacity to do the same job.

 

I think for someone who wants easier fault-finding and minimal fancy electronics the Lynch system with larger batteries may win out, but if you are happy to fault-find complex electronic circuits or believe the system is so reliable fault-finding is not an issue then Ian's system probably wins out with a slightly smaller battery requirement.

[peterboat]

45 minutes ago, Tony Brooks said:

I am afraid the above from Peter seems to prove very little apart from the Lynch system can be configured to produce high powers and thus speed for what reads very like short term "sprint" type uses. That is what I would expect from a brushed DC motor that should give maximum torque and thus devoir maximum current at zero revs. Load it up and pull the revs down the currant rises.

 

I also detect a degree of marketing "information" in there, specifically the talk about what I call face armatures that can be found in many starter motors nowadays.

 

For inland marine use I see the need is for adequate power that can be delivered for long enough in bad conditions like high water flows. The "for long enough" is a function of battery capacity plus current flow. I think the current flow bit is where the "dispute" is. Peter seems to say the Lynch system is good enough for my and my friend's use. Ian seems to say that permanent magnet motors use less electricity for a given power output. That is all exactly as I expect.

 

I think Ian's permanent magnet motors are essentially turned inside out with the permanent magnets being the spinning element and the coils fixed around the outside. That type of motor must be better cooled than one with spinning coils, especially if it is fan or water cooled like alternators.

 

Both will do the job but one, it seems, will do the same job with  smaller and thus cheaper batteries. The other aspect seems to be the cost and efficiency of the control gear and so far I have not noticed Peter giving a comparative cost of the Lynch system that can be directly compared with Ian's. The efficiency of the control gear is important because of the need to deal with waste heat and the amount of electricity such heat wastes, that comes back to battery capacity to do the same job.

 

I think for someone who wants easier fault-finding and minimal fancy electronics the Lynch system with larger batteries may win out, but if you are happy to fault-find complex electronic circuits or believe the system is so reliable fault-finding is not an issue then Ian's system probably wins out with a slightly smaller battery requirement.

Actually Tony if you read the new scientist article it's got good self cooling so it can do the long slog. Now the issue that muddys the water is you have to forget the Lynch system and think Agni, this is Cedrics motors which he has developed forward from the split with the lynch company. A 4QD speed controller at 500 squids is ideal for the job. Now James has a Agni 155R in a 70 x 13.6 40 ton widebeam, he uses it on the tidal Thames at up to 8 hours he doesn't potter around as Ian says that's his assumption not the reality. 

As for electric consumption if you are pottering around like I do the efficiency is very similar to Ian's expensive system. 

The axial flux pancake motor that Cedric has created is well thought of reliable and cheap, its still popular amongst racers because it's tough and reliable and requires no water cooling as it self cools which removes weight not something that matters to us

[IanD]

35 minutes ago, peterboat said:

Actually Tony if you read the new scientist article it's got good self cooling so it can do the long slog. Now the issue that muddys the water is you have to forget the Lynch system and think Agni, this is Cedrics motors which he has developed forward from the split with the lynch company. A 4QD speed controller at 500 squids is ideal for the job. Now James has a Agni 155R in a 70 x 13.6 40 ton widebeam, he uses it on the tidal Thames at up to 8 hours he doesn't potter around as Ian says that's his assumption not the reality. 

As for electric consumption if you are pottering around like I do the efficiency is very similar to Ian's expensive system. 

The axial flux pancake motor that Cedric has created is well thought of reliable and cheap, its still popular amongst racers because it's tough and reliable and requires no water cooling as it self cools which removes weight not something that matters to us

You're repeating the same irrelevant claims.

 

As Tony said, everything you've quoted shows that the Lynch motors can produce plenty of power for relatively short periods. None of them show that they can run at full power for several hours, and neither do your anecdotes about your mate on the Thames.

 

Show us actual evidence that he has run at full power for at least 2 hours -- preferably more -- or stop waffling on about him.

 

There are very good reasons why the Lynch motors are not as good for continuous duty applications like marine as PMAC motors. The first is that they dissipate a lot of heat in the rotor where it's difficult to remove, the second is their small size and weight, the third is air cooling.

 

With PMAC motors all the heat is in the stator windings which are much easier to cool, and especially with liquid -- if you compare air and liquid cooled PMAC motors which are otherwise identical they have the same (very high) peak power, but the liquid cooled one has a considerably higher -- typically double -- long-term power rating because of better cooling.

 

This only really shows up for any motor after some time (depending on the thermal mass) as the motor heats up, which typically takes 10-30mins -- shorter for small light motors like the Lynch, linger for bigger heavier motors like the Engiro. This is why continuous power ratings for marine applications are required to be for at least 2 hours sustained, to make sure the motor temperature has stabilised.

 

In addition DC axial flux motors like the Lynch are considerably less efficient -- especially at full power -- so they have more heat to get rid of, 2.5x more according to the posted curves.

 

I'm afraid you're arguing against fundamental principles of electric motor design here... 😉

 

If you only want to potter about or run for longer periods at well below full power the Lynch motors are fine -- or for intermediate duty applications like cars, bikes, and speed record boats.

 

For anyone who wants to have the certainly that their motor won't overheat when running at full power for 2 hours or more on rivers, they're not so fine -- unless you double them up and underrate them and add belt drives like the Lynch Swordfish, at which point they're more expensive (and still less efficient) than a single PMAC motor.

Edited July 30, 2022 by IanD

[peterboat]

5 minutes ago, IanD said:

You're repeating the same irrelevant claims.

 

As Tony said, everything you've quoted shows that the Lynch motors can produce plenty of power for relatively short periods. None of them show that they can run at full power for several hours, and neither do your anecdotes about your mate on the Thames.

 

Show us actual evidence that he has run at full power for at least 2 hours -- preferably more -- or stop waffling on about him.

 

There are very good reasons why the Lynch motors are not as good for continuous duty applications like marine as PMAC motors. The first is that they dissipate a lot of heat in the rotor where it's difficult to remove, the second is their small size and weight, the third is air cooling.

 

With PMAC motors all the heat is in the stator windings which are much easier to cool, and especially with liquid -- if you compare air and liquid cooled PMAC motors which are otherwise identical they have the same (very high) peak power, but the liquid cooled one has a considerably higher -- typically double -- long-term power rating because of better cooling.

 

This only really shows up for any motor after some time (depending on the thermal mass) as the motor heats up, which typically takes 10-30mins -- shorter for small light motors like the Lynch, linger for bigger heavier motors like the Engiro. This is why continuous power ratings for marine applications are required to be for at least 2 hours sustained, to make sure the motor temperature has stabilised.

 

In addition DC axial flux motors like the Lynch are considerably less efficient -- especially at full power -- so they have more heat to get rid of, 2.5x more according to the posted curves.

 

I'm afraid you're arguing against fundamental principles of electric motor design here... 😉

 

If you only want to potter about or run for longer periods at well below full power the Lynch motors are fine -- or for intermediate duty applications like cars, bikes, and speed record boats.

 

For anyone who wants to have the certainly that their motor won't overheat when running at full power for 2 hours or more on rivers, they're not so fine -- unless you double them up and underrate them and add belt drives like the Lynch Swordfish, at which point they're more expensive (and still less efficient) than a single PMAC motor.

At what cost? What you forget is most boaters run with the tide on rivers as it's what has been done by professional boaters for years.

The lynch gearbox system is 700 squids including pulleys and belt hardly a fortune, I wouldn't buy the lynch system because it's to expensive but the better Agni system I did as its better and cheaper. The problem you have is that you can afford the 30k plus extra for genny for your system the other 99% need something that gets them around cheaply 

[IanD]

45 minutes ago, peterboat said:

At what cost? What you forget is most boaters run with the tide on rivers as it's what has been done by professional boaters for years.

The lynch gearbox system is 700 squids including pulleys and belt hardly a fortune, I wouldn't buy the lynch system because it's to expensive but the better Agni system I did as its better and cheaper. The problem you have is that you can afford the 30k plus extra for genny for your system the other 99% need something that gets them around cheaply 

You keep banging on about the genny (and batteries) which is not the point, the question asked was about what the best type of motor is.

 

You still haven't given a proper cost comparison fot the dual Lynch system; I actually got a quote and it was more expensive than the alternatives.

 

Like I said, if you're happy to pootle around or go with the flow -- an interesting problem on non-tidal rivers, how does that work? -- then a single Lynch is fine, but so is anything else (and other low-cost PMAC motors are now cheaper and better).

 

If you want a boat which can go upstream against significant current (e.g. Ribble Link or Trent) which is what a lot of people -- including me -- have said they want from an electric boat  -- a "go-anywhere" canal boat -- then it isn't.

 

I suggest you stop assuming that just because something works for you it must also work for everyone else with different needs -- you've done this on composting toilets, solar panels, EVs and charging them, and now on electric boats.

 

But I've suggested that before, and you keep on doing it... 😉

[peterboat]

1 minute ago, IanD said:

You keep banging on about the genny (and batteries) which is not the point, the question asked was about what the best type of motor is.

 

You still haven't given a proper cost comparison fot the dual Lynch system; I actually got a quote and it was more expensive than the alternatives.

 

Like I said, if you're happy to pootle around or go with the flow -- an interesting problem on non-tidal rivers, how does that work? -- then a single Lynch is fine, but so is anything else (and other low-cost PMAC motors are now cheaper and better).

 

If you want a boat which can go upstream against significant current (e.g. Ribble Link or Trent) which is what a lot of people -- including me -- have said they want from an electric boat  -- a "go-anywhere" canal boat -- then it isn't.

 

I suggest you stop assuming that just because something works for you it must also work for everyone else with different needs -- you've done this on composting toilets, solar panels, EVs and charging them, and now on electric boats.

 

But I've suggested that before, and you keep on doing it... 😉

You keep on going on about pushing the current on the trent no sensible boaters do that also CRT won't allow you out anyway nowadays and I have done the trent many times always with the tide and current. I gave you a price for the motor and controller but I will talk to Cedric and sort it out for you. I see many boat with small engines pottering around and doing the Trent without issues, maybe they know what they are doing?

As for the ribble link good luck with booking it and getting passage is all I can say

[Tony Brooks]

55 minutes ago, peterboat said:

At what cost? What you forget is most boaters run with the tide on rivers as it's what has been done by professional boaters for years.

The lynch gearbox system is 700 squids including pulleys and belt hardly a fortune, I wouldn't buy the lynch system because it's to expensive but the better Agni system I did as its better and cheaper. The problem you have is that you can afford the 30k plus extra for genny for your system the other 99% need something that gets them around cheaply 

 

But cost should not come into it when  discussing the TECHNICAL merits of each system. The cost comes into it when someone is making a purchasing decision. As far as the purchasing decisions goes I think both of you have made the right decision for yourself.

 

I do not see how any DC motor, permanent magnet or not can ever be as well cooled as the motors that are essentially stepper motors with a permanent magnet rotor. The better cooling where the high current components are arranged around a stationary stator are well known. It is one reason that run-of-the-mill dynamos had  a maximum output of about 30 amps while run-of-the-mill alternators happily produce 70 amps plus. Both dynamos and alternators used forced air cooling. The self same dynamos when sealed with no forced air were limited to about 8 amps (all from memory). That just shows how much heat needs displacing in DC electrical machines, especially those with electromagnetic rotating parts, and waste heat means wasted electricity. If you are claiming the Lynch or Angi motor has a permanent magnet rotor than as far as I know it can not be a pure DC motor. The DC will have to be "chopped up" and directed to the coils around the rotor in a certain order by a controller. I am fairly sure that is how the motors Ian is talking about work.

[Tony Brooks]

8 minutes ago, peterboat said:

You keep on going on about pushing the current on the trent no sensible boaters do that also CRT won't allow you out anyway nowadays and I have done the trent many times always with the tide and current. I gave you a price for the motor and controller but I will talk to Cedric and sort it out for you. I see many boat with small engines pottering around and doing the Trent without issues, maybe they know what they are doing?

As for the ribble link good luck with booking it and getting passage is all I can say

 

All I can say is that when we did the Trent from Keadby I had to go above West Stockwith and stem the tide until the locking out of cruisers was completed and then use full power to move up to the lock and then turn the stern against the tide to get into the lock. I would not like to have tried that in any boat with a questionable power availability. Likewise on the West Stockwith to Cromwell ended up with having to punch the tide for about an hour  after it had turned. That was after the run up from Stockwith with the tide. I think you may be dismissing the concerns people have about that sort of thing a little too lightly.

 

PS that was with a nominal 30 odd HP engine in a 54 ft narrow boat that many people today would consider underpowered. That is about 22 Kw in electrical terms.

[dmr]

I believe that an issue with motors using high tech permanent magnets is that temperature control is essential as overheat destroys the magnets. Maybe things have moved on but I have wrecked a very expensive motor this way😀.

 

There is a lot of argument in this thread but its technically interesting.  There is no right or wrong as there are so many ways to go boating. I talked to a boater who spent their time on the K&A central and western end with a vintage 9horse engine. That was totally adequate, but when they went further and had to go back up through Newbury it was not any good. Some diesels are worse than electric.

 

Many boaters never go on to a river, if you want to spend your life pootling round the four counties ring in silence then a leccy motor is fine. If you want a cheap DIY job (and DIY is good) then 48volts and Lynch are probably the way to go. If you want a go anywhere boat that can do rivers with a fair bit of flow then a much much better system is required, but for that sort of boating a big diesel running on HVO looks like the best option to me.

[peterboat]

22 minutes ago, Tony Brooks said:

 

All I can say is that when we did the Trent from Keadby I had to go above West Stockwith and stem the tide until the locking out of cruisers was completed and then use full power to move up to the lock and then turn the stern against the tide to get into the lock. I would not like to have tried that in any boat with a questionable power availability. Likewise on the West Stockwith to Cromwell ended up with having to punch the tide for about an hour  after it had turned. That was after the run up from Stockwith with the tide. I think you may be dismissing the concerns people have about that sort of thing a little too lightly.

 

PS that was with a nominal 30 odd HP engine in a 54 ft narrow boat that many people today would consider underpowered. That is about 22 Kw in electrical terms.

The last time I went into West Stockwith we arrived at the top of the tide and drifted in on a 67 x 16 working boat timing is everything! With a current running we wouldn't have got in as we no room to spare 

[Tony Brooks]

Just now, peterboat said:

The last time I went into West Stockwith we arrived at the top of the tide and drifted in on a 67 x 16 working boat timing is everything! With a current running we wouldn't have got in as we no room to spare 

We left Keadby as advised by the lockkeeper and had  a fast but no way flat out run up the Stockwith. I suspect it was a very high tide and not much fresh coming down.

[peterboat]

37 minutes ago, Tony Brooks said:

 

But cost should not come into it when  discussing the TECHNICAL merits of each system. The cost comes into it when someone is making a purchasing decision. As far as the purchasing decisions goes I think both of you have made the right decision for yourself.

 

I do not see how any DC motor, permanent magnet or not can ever be as well cooled as the motors that are essentially stepper motors with a permanent magnet rotor. The better cooling where the high current components are arranged around a stationary stator are well known. It is one reason that run-of-the-mill dynamos had  a maximum output of about 30 amps while run-of-the-mill alternators happily produce 70 amps plus. Both dynamos and alternators used forced air cooling. The self same dynamos when sealed with no forced air were limited to about 8 amps (all from memory). That just shows how much heat needs displacing in DC electrical machines, especially those with electromagnetic rotating parts, and waste heat means wasted electricity. If you are claiming the Lynch or Angi motor has a permanent magnet rotor than as far as I know it can not be a pure DC motor. The DC will have to be "chopped up" and directed to the coils around the rotor in a certain order by a controller. I am fairly sure that is how the motors Ian is talking about work.

All I can refer you to is the new scientist article Tony which says they stay cool, I have a bulge fan blowing cool air into the brushes and then through the motor it was on recommendation from James, the motor stays cool even after hours of cruising 

2 minutes ago, Tony Brooks said:

We left Keadby as advised by the lockkeeper and had  a fast but no way flat out run up the Stockwith. I suspect it was a very high tide and not much fresh coming down.

Tickover for us, I have watched some horrendous sights when boaters get it wrong 

[Up-Side-Down]

5 minutes ago, peterboat said:

All I can refer you to is the new scientist article Tony which says they stay cool, I have a bulge fan blowing cool air into the brushes and then through the motor it was on recommendation from James, the motor stays cool even after hours of cruising 

Tickover for us, I have watched some horrendous sights when boaters get it wrong 

Please could you post a link to the New Scientist arti

Just now, Up-Side-Down said:

Please could you post a link to the New Scientist arti

 

Just now, Up-Side-Down said:

Please could you post a link to the New Scientist arti

New Scientist article Peter. Sorry if you've already done so.

[peterboat]

22 hours ago, Up-Side-Down said:

Please could you post a link to the New Scientist arti

 

New Scientist article Peter. Sorry if you've already done so.

Last post page 16 mate 

[PD1964]

22 hours ago, peterboat said:

Tickover for us, I have watched some horrendous sights when boaters get it wrong 

 The mistake a lot of boaters make going from Keadby to West Stockwith, is the get the “speed bug” the thing is to fight temptation and keep the revs off. Or you end up way too early and by the time you do the turn, your a few hundred yards past fighting the tide to get back to the lock😆 

[Tony Brooks]

3 minutes ago, peterboat said:

Last post page 16 mate 

 

But no link so we can read the whole article. Just an assertion it runs cooler with no research methods and data to back it up. I found what looked like an EU patent applications for the Angi Lynch motor and, as far as I understood it, a lot of the armature conductor arrangements have been used in starter motors for probably 100 years. It also seems to be switching coil energization mechanically rather than electronically. Allowing for infant mortality that the warrantee should cover I suspect the electronically switched system would be more reliable.

 

Any component containing electrical conductors revolving inside a casing can only cool via its outer surface whereas a fixed stator can cool via its inner and outer surfaces.

 

It is horses for courses with probably only the size of the battery bank to do a given task being the operational difference.

[peterboat]

6 minutes ago, PD1964 said:

 The mistake a lot of boaters make going from Keadby to West Stockwith, is the get the “speed bug” the thing is to fight temptation and keep the revs off. Or you end up way too early and by the time you do the turn, your a few hundred yards past fighting the tide to get back to the lock😆 

Correct we arrived at still water top of the tide.

[peterboat]

22 hours ago, Up-Side-Down said:

Working now

https://www.newscientist.com/article/mg12416933-000-technology-electric-boat-rides-on-the-current-and-leaves-all-others-in-its-wake/

Edited July 31, 2022 by peterboat

[Tony Brooks]

20 minutes ago, peterboat said:

https://www.newscientist.com/article/mg12416933-000-technology-electric-boat-rides-on-the-current-and-leaves-all-others-in-its-wake/

 

So a 1989 article that is 32 years old. I am sure technology has moved on since then and, as Ian claims, there may well be more electricity frugal systems around now. It is still an assertion with no proof in that article that they run cooler.

 

I have seen too many armatures of whatever design that have thrown their solder for one reason or another to be entirely happy with the cooling of any armature, whatever the shape. However, it still comes down to the difference between yours and Ian's systems functionally is that for a given task yours is likely to need a larger battery bank size.

[peterboat]

Just now, Tony Brooks said:

 

So a 1989 article that is 32 years old. I am sure technology has moved on since then and, as Ian claims, there may well be more electricity frugal systems around now. It is still an assertion with no proof in that article that they run cooler.

 

I have seen too many armatures of whatever design that have thrown their solder for one reason or another to be entirely happy with the cooling of any armature, whatever the shape. However, it still comes down to the difference between yours and Ian's systems functionally is that for a given task yours is likely to need a larger battery bank size.

Tony I have used my boat for a number of years on rivers and canals its been ok and 36kwhs gives me a good cruising range given that solar is replacing what I have used. The motors have had continuous development over the years. If you read all the article you would have read the 24 hour test?

[Tony Brooks]

1 minute ago, peterboat said:

Tony I have used my boat for a number of years on rivers and canals its been ok and 36kwhs gives me a good cruising range given that solar is replacing what I have used. The motors have had continuous development over the years. If you read all the article you would have read the 24 hour test?

 

I have never claimed that your system is not perfectly satisfactory for your budget and use you put it to. In fact, I said that it is probably the right solution for you. You seem a bit too keen to portray your system as the best for boaters whereas Ian seems to better argue and support his choice. You display that less open mind in the electric car topics as well.

[Momac]

53 minutes ago, PD1964 said:

 The mistake a lot of boaters make going from Keadby to West Stockwith, is the get the “speed bug” the thing is to fight temptation and keep the revs off. Or you end up way too early and by the time you do the turn, your a few hundred yards past fighting the tide to get back to the lock😆 

Not only that but entering west Stockwith at high water slack is so much easier.

And the ebb is generally less fierce than the flood so better to arrive an hour after rather than an hour before high water.

We did 5kts through the water which was 7 or 8kts over the ground from Trent end to west Stockwith the other week and that worked just nicely.

The "free fuel" from the tide is welcome after a fuel hungry sea trip.

 

 

 

[peterboat]

4 hours ago, Tony Brooks said:

 

I have never claimed that your system is not perfectly satisfactory for your budget and use you put it to. In fact, I said that it is probably the right solution for you. You seem a bit too keen to portray your system as the best for boaters whereas Ian seems to better argue and support his choice. You display that less open mind in the electric car topics as well.

No I portray it as a cost effective solution not everyone has 30k in their pockets to do the job. Mine is also a DIY option which some of the other systems aren't. Also it's a very much mix and match affair, any brushed speed controller will control that motor, if it doesn't have reverse you can add a reverse contactor with 3 way switch. In essence you can easily collect the parts cheaply like I did and the same with the batteries 

[IanD]

4 hours ago, peterboat said:

No I portray it as a cost effective solution not everyone has 30k in their pockets to do the job. Mine is also a DIY option which some of the other systems aren't. Also it's a very much mix and match affair, any brushed speed controller will control that motor, if it doesn't have reverse you can add a reverse contactor with 3 way switch. In essence you can easily collect the parts cheaply like I did and the same with the batteries 

Peter, why don't you stop the "30k" bullsh*t?

 

We're not talking about the cost of a complete system including batteries and generator here -- cheap secondhand or new and expensive -- we're talking about the motor (and controller), which was the question that was asked.

 

I provided quotations showing that in an apples-to-apples "go-anywhere" comparison (15kW continuous) your favourite Lynch solution was not cheaper, in fact it was more expensive.

 

As a cheap DIY solution it's OK for pootling around like you do -- it's fine if you're happy with that, but please stop claiming that it can meet the needs of boaters looking for a "go-anywhere" solution, unless you (or your mate James) have *actual evidence* that it can sustain full power for several hours -- which is what many people have said they would need to be sure of to switch to an electric boat.

 

There's nothing wrong with a cheap DIY system based on a Lynch motor if that's what you want/need. But it can't do the same job as one based on newer PMAC technology -- and if it tries to compete (dual motors and controllers) it's no longer cheaper, and it's less efficient, noisier, and runs hotter. This really is a case where modern technology *is* better, which is why all EVs use it... 😉

 

And of course you can do a DIY system using PMAC motors and controllers (cheap or expensive) just as easily as a DC Lynch one -- you buy a motor and a controller and connect them to the battery... 😉

Edited July 31, 2022 by IanD

[peterboat]

1 hour ago, IanD said:

Peter, why don't you stop the "30k" bullsh*t?

 

We're not talking about the cost of a complete system including batteries and generator here -- cheap secondhand or new and expensive -- we're talking about the motor (and controller), which was the question that was asked.

 

I provided quotations showing that in an apples-to-apples "go-anywhere" comparison (15kW continuous) your favourite Lynch solution was not cheaper, in fact it was more expensive.

 

As a cheap DIY solution it's OK for pootling around like you do -- it's fine if you're happy with that, but please stop claiming that it can meet the needs of boaters looking for a "go-anywhere" solution, unless you (or your mate James) have *actual evidence* that it can sustain full power for several hours -- which is what many people have said they would need to be sure of to switch to an electric boat.

 

There's nothing wrong with a cheap DIY system based on a Lynch motor if that's what you want/need. But it can't do the same job as one based on newer PMAC technology -- and if it tries to compete (dual motors and controllers) it's no longer cheaper, and it's less efficient, noisier, and runs hotter. This really is a case where modern technology *is* better, which is why all EVs use it... 😉

 

And of course you can do a DIY system using PMAC motors and controllers (cheap or expensive) just as easily as a DC Lynch one -- you buy a motor and a controller and connect them to the battery... 😉

I keep on telling you it's not a lynch system but you don't listen perhaps its deliberate and it suits your price argument 🤣