Why hybrid?

[Adelie]

Going back to the original question of "Why Hybrid?"

I'm going to revise my earlier conclusion that it probably isn't any savings it for long distance cruisers. It think there would be significant savings for cruisers that motor longer distances and especially those who chose to slow motor, i.e. S/L-0.75.

From the tractor engine data it appears that while smaller motors are less efficient than larger ones at peak HP, they are more efficient than a larger motor operating at or near the smaller motor's peak hp. That is a 25hp ICE is going to be more efficient at 20hp than a 100hp ICE operating at 20hp. I'll crunch more numbers on this.

Regardless. Because of the 20% ICE efficiency loss between peak hp and 50% hp which is what seems to be the consensus cruising power, intermittently running the ICE at full power and efficiency propelling and recharging the battery alternating with electric-drive as soon as the battery is full will use less fuel. For LFP battery losses are about 7%, electric drive losses are 5-10%, let's call it 8%. 15% loss compared to max hp, or a 5% gain compared to ICE only/ That means there's at least a 5% fuel efficiency advantage when under Hybrid electric drive and a 20% advantage when under hybrid ICE-drive. The net efficiency advantage is going to depend on what the split between ICE-drive and Electric-drive. I'm going to do more math on this too.

The slower you go the bigger the spread between ICE and hybrid efficiency. Both are still improving their mpg but hybrid is improving much faster.

The total fuel cost savings per year depends on boat size, how many miles a year you motor ad what speed you prefer to motor at.
For new builds or engine replacements, if you k ow your time horizon for selling the boat you can figure whether it is worth the added cost of hybrid.

Hybrid still isn't worth it if you have a working ICE motor, the fuel savings aren't going to make it worthwhile to dump a working motor in good condition.

[donradcliffe]

Originally Posted by Adelie

Going back to the original question of "Why Hybrid?"

I'm going to revise my earlier conclusion that it probably isn't any savings it for long distance cruisers. It think there would be significant savings for cruisers that motor longer distances and especially those who chose to slow motor, i.e. S/L-0.75.

From the tractor engine data it appears that while smaller motors are less efficient than larger ones at peak HP, they are more efficient than a larger motor operating at or near the smaller motor's peak hp. That is a 25hp ICE is going to be more efficient at 20hp than a 100hp ICE operating at 20hp. I'll crunch more numbers on this.

Regardless. Because of the 20% ICE efficiency loss between peak hp and 50% hp which is what seems to be the consensus cruising power, intermittently running the ICE at full power and efficiency propelling and recharging the battery alternating with electric-drive as soon as the battery is full will use less fuel. For LFP battery losses are about 7%, electric drive losses are 5-10%, let's call it 8%. 15% loss compared to max hp, or a 5% gain compared to ICE only/ That means there's at least a 5% fuel efficiency advantage when under Hybrid electric drive and a 20% advantage when under hybrid ICE-drive. The net efficiency advantage is going to depend on what the split between ICE-drive and Electric-drive. I'm going to do more math on this too.

The slower you go the bigger the spread between ICE and hybrid efficiency. Both are still improving their mpg but hybrid is improving much faster.

The total fuel cost savings per year depends on boat size, how many miles a year you motor ad what speed you prefer to motor at.
For new builds or engine replacements, if you k ow your time horizon for selling the boat you can figure whether it is worth the added cost of hybrid.

Hybrid still isn't worth it if you have a working ICE motor, the fuel savings aren't going to make it worthwhile to dump a working motor in good condition.

So you want to double your capital cost for a 5% gain in efficiency in a mode you use less than 10% of the time. I've got a bridge to sell you.

[PineyWoodsPete]

Originally Posted by Adelie

I make it 58kW @3200rpm.
58hp /0.746kW/hp = 77.75hp.
77.75hp / 4.76gal/hr = 16.3 hp-hr/gal.

50% load and 16% loss of efficiency.

This is presuming that the propellor curve matches what is installed on your boat. It's probably close so I wouldn't quibble with your numbers.
Your engine is very new and very large so 19.4 hp-hr/gal is not unreasonable.

We were both a bit off, but in diff. directions reading the low-scale curve. As PD is an entirely mathematical construct and a cubic function, let's cube the 3200/4000 fraction: 0.8 cubed = 0.512 X 121kW = 62kW = 82.6HP/4.76 GPH = 17.36 HP/gal-hr.

The fascinating thing to me is that to construct your own PD curve, all you need to know is HP at WOT under way in relatively flat conditions. Since the common HP vs RPM curve for your engine is constructed with WOT at each measured RPM - basically measured by the torque it takes to brake down to that RPM (brake HP) - this is the starting point. Then, at say 50% your max, 0.5 cubed = 0.125 for 1/8th the max power. Looking at the rounded table on my previous post, that's only 15kW @ 2000RPM vs 121kW @ 4000. Pretty astounding! Fuel consumption mirrors this pretty closely.

[Adelie]

Originally Posted by donradcliffe

So you want to double your capital cost for a 5% gain in efficiency in a mode you use less than 10% of the time. I've got a bridge to sell you.

There would be a 5-15% gain in efficiency at 80%rpm, not 5%.
I didn't write that it would be worth it, I believe I wrote that the savings are not insignificant as I had previously written.

It's more likely to be worth it the more miles you motor a year and the slower you motor.

For me, I'm going to go full EP with an outboard backup which looks to be cheaper than or the same cost as replacing an Atomic-4.

[s/v Jedi]

Originally Posted by Adelie

There is a gain in efficiency from not cycling on and off, but if the unit is sized to the need there is a 100% duty cycle and VSD would provide little or no improvement. That said it's hard to find small units sized for boat use and the Peltier units have relatively low efficiency to begin with.

Originally Posted by wingssail

I am not sure about the 50% less energy consumption. The technical specifications for a velair i10 https://www.uflexusa.com/wp-content/...hure-pages.pdf shows a power consumption of 6.2 amps. My Midea 8000BTU has a similar power requirement, a soft start, and an energy saving cycle and costs about 17% of the Velair, (which also needs installation and water cooling pump).

So a window unit is rather inelegant but it provides good cooling for a low price and takes less room on the boat for installation.

Plus, I can swing it on and off in seconds with a halyard so I don't need to take it when we go racing.

We have used window unit AC's for about 20 years. They fit our boat. They have been cost effective and when one breaks we just replace it the same day with a trip to an appliance store. This new one, (the Midea 8000BTU) is much smaller, much quieter, and my electric bill this summer has been about $110 per month instead of $250 per month with my last unit, which was an LG 8000BTU, so we're thrilled.

Study it, even here on CF there are actual users reporting this. Maybe I exaggerate and it’s 40%. Google says it’s 40%.

The technical specifications shows maximum amperage. VSD means it’s variable. Also, it’s not a soft start device.

I don’t know why I post this anymore, I think it’s better y’all stick with the old kit

[CatLove]

the Midea 8000BTU is a very efficient unit because it is inverter driven ( aka VSD ). It's rated 15 BTU/H/Watt.

[wingssail]

Originally Posted by s/v Jedi

Study it, even here on CF there are actual users reporting this. Maybe I exaggerate and it’s 40%. Google says it’s 40%.

The technical specifications shows maximum amperage. VSD means it’s variable. Also, it’s not a soft start device.

I don’t know why I post this anymore, I think it’s better y’all stick with the old kit

Jedi, We-all are not sticking with the old kit because we think the new stuff is not better, it's because we can't see spending $2000-$4000 which we don't have for a device which, for all its glorious stainless steel magnificence and technical marvel, doesn't make our boat any colder than our $300 device for, as far as I can see, any less power.

And it won't friggin fit in our boat!

Yet you distain it.

I think there are people who fan-boys of the specifications and are too far economically out of touch to consider that "the best" isn't always the best choice.

[Shaneesprit]

Originally Posted by Adelie

See my post #145. For the vehicle I checked the improved gas mileage paid for the added cost of the upgrade to hybrid in less than 3yr.

Road vehicles are a completely different situation than vessels or trains, they get regenerative braking, and the electric dive allow them to use alternative engine cycles like Atkinson cycle engine which is more efficient than the Otto cycle normally used in gas/petrol cars.

I agree vehemently with the sail more motor less or better only if you can’t help it sentiment.

For trains they can and should convert to electric overhead catenary. But the US being so large and consistently having relatively cheap fuel has meant there was no push to pay install the catenaries.

Trains are diesel electric in the UK as well. All the Hybrid does is stop the engine while they are in the Capital. The overall emIssions are higher - Fuel is not cheap here we laugh at you, when you cry about fuel prices.

Road vehicles don’t gain as much as you think.
I think a deeper understanding of Hybrid is needed here, take my commute this morning around 110miles by car roughly speaking I touched the brake pedal for around 20seconds of this 2h journey, and that’s including a stop - so where is the regenerative braking coming from? Because 20seconds of fairly light braking is going to get you nothing.
OK so what a Hybrid is better in stop start traffic? So you know that emissions are checked and legislated on a warm engine not a cold one, and that’s very important. So let’s say I live in a city leave my house and drive in that stop start traffic. Well now the Hybrid becomes one of the most poisonous vehicles on the planet, because cold emissions are really bad, especially from those with catalytic converters aka all of them. But Catalytic are another story.

VOCS - I have been aware of these since the early 1990s so it’s not news to me.
You know that rotten egg smell behind a driver with a cold engine!
Please read up on cold emissions, the dirty secret of the Hybrid world, these exist in all modern ICE except the Hybrid gives you the opportunity to extend the poisonous period in warm up with its stop start technology. Climate scientists are not with you on this one.
Official numbers are not a great way to determine the likely outcome in the real world. Here is a couple of links to get you thinking - and a later thought - Elon Musk doesn’t make a Hybrid!

[s/v Jedi]

Originally Posted by wingssail

Jedi, We-all are not sticking with the old kit because we think the new stuff is not better, it's because we can't see spending $2000-$4000 which we don't have for a device which, for all its glorious stainless steel magnificence and technical marvel, doesn't make our boat any colder than our $300 device for, as far as I can see, any less power.

And it won't friggin fit in our boat!

Yet you distain it.

I think there are people who fan-boys of the specifications and are too far economically out of touch to consider that "the best" isn't always the best choice.

You seem to think that I have an interest in what gear you have aboard, or if you would buy something or not. Sorry, it isn’t about you or your boat, we were discussing the pro’s and con’s of A/C units when powering them from batteries. You state that the new VSD units are not saving any power compared to the old which is not true and I tried to explain how and why. Yet, you persist and now it appears because you don’t want to buy one.

I did write that I still have an old unit, that I think those new units are expensive etc. but that doesn’t mean my gear is just as good… it’s rubbish compared to the new gear. How hard is that to accept? My gear is rubbish and your gear is just as rubbish as my gear. But that doesn’t make the new gear the same kind of rubbish… no, the new gear is great, saves 40% energy and during startup pulls 7A from a house battery instead of 250A.

That’s what I mean. We’re talking about the products, not about if we can afford it or have it or can fit it aboard. Whatever we have or do is irrelevant to comparing the performance of products.

[wingssail]

Originally Posted by CatLove

the Midea 8000BTU is a very efficient unit because it is inverter driven ( aka VSD ). It's rated 15 BTU/H/Watt.

Thanks for that, How did you find this (I guess I bought it by accident)? I couldn't find the technology or specs for the unit MAW08C1OUM.

[s/v Jedi]

Originally Posted by CatLove

the Midea 8000BTU is a very efficient unit because it is inverter driven ( aka VSD ). It's rated 15 BTU/H/Watt.

Yes, I actually own one of those for use while on the hard. I can run it off a 1,200W inverter, it’s amazing and super efficient even though this is impossible according to others

Edit: oh my, it says it only saves 35% energy! ;-)

[wingssail]

Originally Posted by s/v Jedi

...we were discussing the pro’s and con’s of A/C units when powering them from batteries. You state that the new VSD units are not saving any power compared to the old which is not true and I tried to explain how and why. Yet, you persist and now it appears because you don’t want to buy one.

Sorry Jedi, you have this all wrong. I am not disputing the effectiveness of new technology or "persisting" because I don't want to buy one.

We are all discussing the pro's and con's of AC units and you mentioned a Velair unit and seemed impressed with its efficiency and lack of start surge. I mentioned a Midea unit I purchased and how it seemed to have similar pro's regarding efficiency and low start surge as well as size, weight, ease of installation and particularly cost.

Nowhere did I say new VSD units are not saving power compared to "old" units, only that it seems that the savings are questionable when my own experience is that comparable power savings can be achieved at a huge savings of cost and installation headache with some newer window units. Definitely a pro and con discussion which could pertain to using AC on battery power. (Are there affordable options which can achieve similar savings? Answer: Maybe Yes)

But another point you seem to have missed is that I observed that your focus seems to be solely on the technical features without regard to the cost and some of the solutions you describe could be out of reach for other CF readers. We love reading your posts and all learn from them, but please have some mutual respect for those who have considerations in addition the technical excellence you espouse. The tone of your comment seems to exclude that mutual respect.

Don't wish to get into an endless argument on this (and I won't), just hoping you will take it to heart without offense.

[wingssail]

Originally Posted by s/v Jedi

Yes, I actually own one of those for use while on the hard. I can run it off a 1,200W inverter, it’s amazing and super efficient even though this is impossible according to others

Edit: oh my, it says it only saves 35% energy! ;-)

That is not the Midea unit I have (it's MAW08C1OUM), and the measured power savings for 4 months is over 50%. I suspect it is an inverter unit with VSD, based on its operating characteristics but I don't see that in any spec from Midea)

Its clearly fair to question the quoted power savings of the top units when similar savings may be obtained with the newer consumer units.

[Adelie]

Originally Posted by Shaneesprit

Trains are diesel electric in the UK as well. All the Hybrid does is stop the engine while they are in the Capital. The overall emIssions are higher - Fuel is not cheap here we laugh at you, when you cry about fuel prices.



Road vehicles don’t gain as much as you think.

I think a deeper understanding of Hybrid is needed here, take my commute this morning around 110miles by car roughly speaking I touched the brake pedal for around 20seconds of this 2h journey, and that’s including a stop - so where is the regenerative braking coming from? Because 20seconds of fairly light braking is going to get you nothing.

OK so what a Hybrid is better in stop start traffic? So you know that emissions are checked and legislated on a warm engine not a cold one, and that’s very important. So let’s say I live in a city leave my house and drive in that stop start traffic. Well now the Hybrid becomes one of the most poisonous vehicles on the planet, because cold emissions are really bad, especially from those with catalytic converters aka all of them. But Catalytic are another story.



……

Diesel electric in trains is not hybrid, there is no energy storage for the electricity. Diesel-electric is used on trains because it can apply full tractive effort at zero speed. Mechanical clutch’s and transmissions can’t do this without dying very quickly.

Hybrid vehicles isn’t just about regenerative braking, it’s also about using different engine cycles that are more efficient but have less power for the engine size. The low power of the engine is made up for with electric-drive.

Take the Kia Sportage.
ICE model is 25/32mpg (city/highway)
Hybrid is 42/44mpg.

Regenerative braking doesn’t give you an extra 12mpg on the freeway, a more efficient engine does.

But once again, car use patterns aren’t the same as cruising boats.

While fuel prices remain relatively low, users will prioritize power over efficiency.

When that happens I expect Diesel engines may be redesigned for higher efficiency. Applying Atkinson cycle to a Diesel might provide about 50% better fuel efficiency at the cost of 1/3-1/2 the power in an engine the same weight. And you couldn’t add a turbo to make up for that, there is not enough energy left in the exhaust. I don’t know if it would work with diesel the way it does with Otto cycles.

[emilecantin]

Originally Posted by Shaneesprit

Road vehicles don’t gain as much as you think.
I think a deeper understanding of Hybrid is needed here, take my commute this morning around 110miles by car roughly speaking I touched the brake pedal for around 20seconds of this 2h journey, and that’s including a stop - so where is the regenerative braking coming from? Because 20seconds of fairly light braking is going to get you nothing.
OK so what a Hybrid is better in stop start traffic? So you know that emissions are checked and legislated on a warm engine not a cold one, and that’s very important. So let’s say I live in a city leave my house and drive in that stop start traffic. Well now the Hybrid becomes one of the most poisonous vehicles on the planet, because cold emissions are really bad, especially from those with catalytic converters aka all of them. But Catalytic are another story.

VOCS - I have been aware of these since the early 1990s so it’s not news to me.
You know that rotten egg smell behind a driver with a cold engine!
Please read up on cold emissions, the dirty secret of the Hybrid world, these exist in all modern ICE except the Hybrid gives you the opportunity to extend the poisonous period in warm up with its stop start technology. Climate scientists are not with you on this one.
Official numbers are not a great way to determine the likely outcome in the real world. Here is a couple of links to get you thinking - and a later thought - Elon Musk doesn’t make a Hybrid!

https://www.google.com/amp/s/www.bbc...t-54170207.amp

So reading that and a little research for yourself, if a Hybrid is better on the road than in a boat, as you stated. Well it doesn’t stack up very well at all does it?

Have you actually driven a hybrid car? I used to have a Chrysler Pacifica Hybrid (which is a PHEV), and from just this car, there are 2 things you got wrong:

1- When the gas engine starts, it keeps running until it gets warm. Then it'll run periodically for the rest of your drive, again to keep it warm. This is done specifically to address the cold catalytic converter issue.

2- The hybrid version of the Pacifica has a very similar engine to the gas version (same displacement, pretty sure it's the same block), but it's making a lot less HP because it's running the Atkinson cycle, which develops less HP but is more fuel-efficient than the more common Otto cycle. It doesn't show when driving the car because the loss in HP is more than compensated by the 2 electric motors.

To give real numbers, I was averaging about 8L/100Km when I wasn't charging it, both highway and city driving. A previous car I had which was pretty similar (Dodge Grand Caravan) could go as low as 9.5L/100Km on the highway if I was very careful. City driving was more around 14-15L/100Km.

So yes, I saw real efficiency gains in pretty much the same car even compared to the "ideal" scenario for a gas engine (highway at constant speed) which is pretty similar to boat usage.