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Old 02-26-2019, 10:52 AM   #1
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New tech applications could make Generators optional!

I've read many threads in TF that circle around the need for a viable solution to questions such as; "generator or no generator onboard?", "best energy storage systems?", and "running air conditioning at anchor?".

Good article about the marriage of 2 technologies emerging in the recreational marine industry that make a generator optional or at the least, downgraded to lower kw units.

Don't shoot the messenger, I just think this is helpful.

https://www.passagemaker.com/technic..._hsmi=70238631
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Old 02-26-2019, 11:11 AM   #2
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The products mentioned in the article help but do not really solve the problem of running the A/C at anchor. If you were to marry the Webasto Blue Cool A/C with Volta's Li battery, inverter and propulsion engine driven auxiliary alternator you might have a workable system but at what cost?


The Blue Cool uses 10% less power while running and admittedly the startup amps are very low, but that in itself doesn't do much. MasterVolt has had a generator/inverter/house battery bank system for a long time that starts up the small generator only when needed. Combining that product with a lower powered A/C and a higher capacity Li bank would be a better solution I believe and probably cheaper.


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Old 02-26-2019, 11:23 AM   #3
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Lots of neat ways to mix high tech inverters, batts, aircon, gennies, etc into a very efficient system. Lots of fun playing with the configurations and tweaking designs to fit a need.

Downside is cost and complexity. Added all up and the high tech system is much more expensive than a dumb gennie and simple induction motor aircon.

Just did an investigation on a boat damaged by a lightning strike. Amazing how expensive that became replacing engine ECM's, electronic helm controls, aircon controls, helm electronics, etc, etc. Anything digital was fried.

Still neat stuff.
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Old 02-26-2019, 11:47 AM   #4
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So much confusion, so little time. If you have ever been interviewed for a technical publication, then read the resulting article, you'll never believe anything you read in a journal, ever again.


First off, I think someone mixed up days and hours. a 5 ton HVAC unit consumes about 17kw. Let's assume runs at a 50% duty cycle, so consumes around 8 kw per hour. The max battery bank referenced is 96kwh, so that would power the HVAC for about 12 hrs, not 13 days. If it can run for 13 days, that's some serious magic.



Trimming the start surge load is good, but frankly, how big a problem is it really? And a variety of soft-start devices are available when it is a problem. And another way to trim off the start surge load is with a load-boosting inverter commonly available for 10+ years. Those supplement surge loads with inverter power, having the same trimming effect.


But there is also a down side inverter drives like those used in variable speed HVAC units, and our own Maerin is experiencing it now. Inverter drives draw a disproportionate portion of their power at the crest of voltage AC wave form, and can screw up other devices that are looking for that crest. The solution offered by the generator manufacturers is to up-side the generator so these so-called non-linear loads are a smaller portion of the total load capacity. So look what's happened. You switched to an inverter driven variable speed HVAC unit to reduce your generator size, only to find that you need to now increase your generator sizer to run it. How messed up is that?


I'm actually anxiously awaiting some practical experience on this with out new boat. Our HVAC chillers are variable speed, working exactly like the units described. They do bring some benefits, but start up surge is very low on the list. Benefit one is that you can limit the power draw so you don't trip a shore breaker, or so you can run on a smaller generator. With fixed power units, all you can do is turn off the HVAC is parts of the boat, where with a variable speed/power unit you can run everything, just with less capacity. Also, it solves the issue of all the individual units coming on at once and over loading the power source. Another benefit is that you can run with just two chillers rather than an bunch of individual units. If a unit fails, you keep going, where with individual units a failure takes out HVAC is some part of the boat. Oh, and they do inherently have soft start.


The down side is that I don't know what the impact of their non-linear load will be. Fingers crossed.
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Old 02-26-2019, 12:05 PM   #5
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Wifey B: Please help me understand. Why the antipathy toward generators? Is it a sailing mentality? Is it a bad experience in a previous life? I see it in sailboaters and in a significant part of the trawler population but not in other boats. Is it from ancient times when they were noisy?
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Old 02-26-2019, 12:15 PM   #6
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Not antipathy. It's just that there are lots of sources of energy, and lots of ways of managing that energy on a boat. And a gennie is a rather crude (yet effective) source.

Gets engineers to scratch their heads and say "there has got to be a better way".

That's what you are seeing here.
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Old 02-26-2019, 12:20 PM   #7
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Wifey B: Please help me understand. Why the antipathy toward generators? Is it a sailing mentality? Is it a bad experience in a previous life? I see it in sailboaters and in a significant part of the trawler population but not in other boats. Is it from ancient times when they were noisy?
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Old 02-26-2019, 12:27 PM   #8
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Not antipathy. It's just that there are lots of sources of energy, and lots of ways of managing that energy on a boat. And a gennie is a rather crude (yet effective) source.

Gets engineers to scratch their heads and say "there has got to be a better way".

That's what you are seeing here.
Wifey B: I see this thread with engineer thoughts but read so many going to such effort to avoid them when they don't have a better solution. Perhaps soon we'll be talking about gas and diesel engines in the same way, as crude, yet effective, sources.

I'm not saying exploring options isn't wise. However, I also see many spending a lot of time and money trying to circumvent them and others sacrificing a lot of comfort in trying to do the same.

Hoping the engineers keep at it, but meanwhile I'll just enjoy and be happy to have generators.
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Old 02-26-2019, 12:32 PM   #9
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Wifey B: Please help me understand. Why the antipathy toward generators?
I can't speak for all. I think there is a spectrum of people.

I've noticed that there is a faction of the sailing crowd that doesn't want ANY combustion 'noisemaker' at all. Some tolerate the 'auxiliary' some strive to go engineless.

I think there is another faction that wants to avoid or reduce dependence on something that might introduce catastrophe in multiple systems should it fail. (electric stove, battery charger, fridge, freezer, AC).

For me, I am attempting to reduce run-time. To me, it occasionally becomes an inconvenient obligation. I don't like to run the generator unattended. I hate that I have to work my day around a morning and evening 'runtime'. I would like to reduce the duration of time that the generator needs to run to allow more flexibility in daily activities.
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Old 02-26-2019, 01:23 PM   #10
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Don't forget about us who have suitably sized vessels with space for gensets, washers, dryers, microwaves, ACs, floor heaters, water heaters, Chargers, inverter/chargers (configured to suit) batteries (of any type), diesel furnaces, refrigerators, freezers, ice makers, TVs, entertainment center and all that bulky stuff that needs ready kilowatts at the flick of a switch.

Gensets are wonderful machines. They last for decades if installed correctly and are maintained properly. They are not old school. They are yesterday, today and tomorrow.

Hundreds of thousands are made every year and used everywhere. Remote locations, ships, hospitals, emergency fire systems, ball games, boat shows, RVs, hurricane relief etc. the list is endless.

As my friend Kevin Saunders says, I have a genset and I'm not afraid to use it. I and tens of thousands of other boaters are with him.
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Old 02-26-2019, 01:44 PM   #11
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Wifey B: Please help me understand. Why the antipathy toward generators?
I'm happy without a generator on the boat for a number of reasons.

They take up valuable space on a small boat. I could squeeze one in, but access for servicing would be very tight.
Our electricity requirements are small. We prefer cooking with gas, so electricity isn't required for a stove. LED's have reduced the power required for lighting.
Although we have hot summers (over 100F today in Adelaide), it is a dry heat similar to Phoenix's and on the water it is always cooler. A/C isn't required. A swim during the day and a fan at night keeps us comfortable.
We don't watch TV, we don't own an electric coffeemaker, the fridge/freezer is DC, we make toast over the gas stove.

We have a small invertor, but don't use it as everything on the boat is DC.
With one 250 watt solar panel we can keep batteries charged indefinitely.

What are we missing?
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Old 02-26-2019, 02:04 PM   #12
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I'm happy without a generator on the boat for a number of reasons.

They take up valuable space on a small boat. I could squeeze one in, but access for servicing would be very tight.
Our electricity requirements are small. We prefer cooking with gas, so electricity isn't required for a stove. LED's have reduced the power required for lighting.
Although we have hot summers (over 100F today in Adelaide), it is a dry heat similar to Phoenix's and on the water it is always cooler. A/C isn't required. A swim during the day and a fan at night keeps us comfortable.
We don't watch TV, we don't own an electric coffeemaker, the fridge/freezer is DC, we make toast over the gas stove.

We have a small invertor, but don't use it as everything on the boat is DC.
With one 250 watt solar panel we can keep batteries charged indefinitely.

What are we missing?

Sounds to me like you aren't missing a thing. As you say, your electricity requirements are small. Perfect application for solar panels and inverter.
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Old 02-26-2019, 03:56 PM   #13
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I'm happy without a generator on the boat for a number of reasons.

They take up valuable space on a small boat. I could squeeze one in, but access for servicing would be very tight.
Our electricity requirements are small. We prefer cooking with gas, so electricity isn't required for a stove. LED's have reduced the power required for lighting.
Although we have hot summers (over 100F today in Adelaide), it is a dry heat similar to Phoenix's and on the water it is always cooler. A/C isn't required. A swim during the day and a fan at night keeps us comfortable.
We don't watch TV, we don't own an electric coffeemaker, the fridge/freezer is DC, we make toast over the gas stove.

We have a small invertor, but don't use it as everything on the boat is DC.
With one 250 watt solar panel we can keep batteries charged indefinitely.

What are we missing?
Wifey B: Missing many things but none that are important to you. That's the key. If you don't feel deprived, then it's all great.

To me, it would feel like camping, which I've never done.
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Old 02-26-2019, 09:33 PM   #14
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I couldn't find the article I wanted but this gives the basic idea.

https://www.sciencedirect.com/scienc...60319977900209

Quote:
Abstract

The 43įF (24įC) temperature difference that exists between surface water and deep water at selected sites in tropical oceans can be used to drive a heat engine to produce electric power, electrolyze water, and produce ammonia from the resulting hydrogen plus nitrogen from the air. A baseline design has been developed for a 100-MWe Ocean Thermal Energy Conversion (OTEC) plant-ship that would produce 313 tons per day of ammonia. The cost estimates for this design have been extrapolated to 500-MWe plant-ships to produce ammonia (for fertilizers and chemicals) or liquid hydrogen for shipment to the U.S. It is judged that ammonia will be producible at competitive cost ($96/short ton in 1975 dollars) by the sixth and subsequent plant-ships in the mid-1980s. This production by OTEC/ammonia plants would conserve supplies of natural gas or other fossil fuels now used to produce ammonia on shore. For the longer term (1990s), liquid hydrogen from OTEC plants should become competitive as demands for this clean fuel and efficient ways for employing it in larger markets (fuel cells, transportation, etc.) come to maturity
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Old 03-16-2019, 10:42 AM   #15
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Do larger marine AC systems use a soft start capacitor? Most of the refrigerant compressors around my house use them, AC and fridge. Even my washer has a soft start capacitor. I was contemplating adding one if the AC system I chose doesn't have one. I wouldn't run AC much. I live in the SE and I don't use AC now, but I know how hot it can get on a boat in 100-degree heat.
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Old 03-17-2019, 06:03 AM   #16
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"Do larger marine AC systems use a soft start capacitor?"


A soft start setup is simple to add on (if not factory) and is a good low cost solution to crap dock power.
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Old 03-17-2019, 07:31 AM   #17
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This is not my area of expertise, but I think there is a difference between a Start Capacitor, and a Soft Start device. As I understand it, a Start Capacitor is a required part of any single phase motor to get it started. A Soft Start device is something in addition to that to control start up in-rush current.


Perhaps someone more knowledgeable on this can expound?
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Old 03-17-2019, 01:10 PM   #18
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This is not my area of expertise, but I think there is a difference between a Start Capacitor, and a Soft Start device. As I understand it, a Start Capacitor is a required part of any single phase motor to get it started. A Soft Start device is something in addition to that to control start up in-rush current.


Perhaps someone more knowledgeable on this can expound?
You're probably right. I've always heard appliance techs refer to the capacitors as soft starts. We know techs terminology isn't always right though.
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Old 03-17-2019, 01:51 PM   #19
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At the risk of adding further to the "discussion" I will add this.

THere is the typical START capacitor which many single phase motors require to get going. Any smaller boat A/C unit will have this type of motor. They are fine if the supply has sufficient voltage capacity such as your house or the dock plug in if big enough or a decent size generator.

There is also a HARD START capacitor which is effectively just a larger capacitor then would normally be installed. They produce a stronger startup torque plus supply some of the initial start up current which means the motor gets through the high inrush current stage. They charge within a couple A/C cycles, far faster than the motor can get going thus partly the boost.

These Hard start caps. are fairly common in the RV world since many people have A/C s and want/ need to run them on a Honda/Yamaha 2000 W generator. That Hard start unit can make the difference between a startup or a tripped C.B. and a no start.

The SOFT START is an electronic control that actually that controls the voltage from a lower point to the motor ramping up the voltage to speed up the motor over a bit of time avoiding the high inrush current so avoiding the tripped C.B.. There are a couple different means of modifying the voltage the motor sees. Sounds like these may be gaining more favour in the RV world.

The Hard START caps are usually inexpensive for most small A/C, $75 or thereabouts and can often be user installed even if you don't know a lot. Often/usually can simply replace the existing capacitor in the original mounting spot. Be carefull about discharging the existing cap. as they can hold a dangerous voltage for a long period of time. Of course they won't always work.

The SOFT STARTS are much more money, or at least used to be when I played with similar, and are more involved to install. Larger also ,so may not fit in the A/C unit but need to be mounted elsewhere but they are effective.

There was a previous thread about this which I did not bookmark and the poster went with a SOFT START for good reasons. You might contact him with a PM through this site.

Found it:
Soft Starting for air conditioners with Micro-Air
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Old 03-17-2019, 04:02 PM   #20
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At the risk of adding further to the "discussion" I will add this.

THere is the typical START capacitor which many single phase motors require to get going. Any smaller boat A/C unit will have this type of motor. They are fine if the supply has sufficient voltage capacity such as your house or the dock plug in if big enough or a decent size generator.

There is also a HARD START capacitor which is effectively just a larger capacitor then would normally be installed. They produce a stronger startup torque plus supply some of the initial start up current which means the motor gets through the high inrush current stage. They charge within a couple A/C cycles, far faster than the motor can get going thus partly the boost.

These Hard start caps. are fairly common in the RV world since many people have A/C s and want/ need to run them on a Honda/Yamaha 2000 W generator. That Hard start unit can make the difference between a startup or a tripped C.B. and a no start.

The SOFT START is an electronic control that actually that controls the voltage from a lower point to the motor ramping up the voltage to speed up the motor over a bit of time avoiding the high inrush current so avoiding the tripped C.B.. There are a couple different means of modifying the voltage the motor sees. Sounds like these may be gaining more favour in the RV world.

The Hard START caps are usually inexpensive for most small A/C, $75 or thereabouts and can often be user installed even if you don't know a lot. Often/usually can simply replace the existing capacitor in the original mounting spot. Be carefull about discharging the existing cap. as they can hold a dangerous voltage for a long period of time. Of course they won't always work.

The SOFT STARTS are much more money, or at least used to be when I played with similar, and are more involved to install. Larger also ,so may not fit in the A/C unit but need to be mounted elsewhere but they are effective.

There was a previous thread about this which I did not bookmark and the poster went with a SOFT START for good reasons. You might contact him with a PM through this site.

Found it:
Soft Starting for air conditioners with Micro-Air



Good post.



VFDs (variable-frequency drives) are being touted as the in thing for electric motors on a couple of other forums I follow. From my understanding these are mainly for AC voltage motors. They can be over the top expensive.



https://en.wikipedia.org/wiki/Variable-frequency_drive
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