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Old 13-11-2017, 16:04   #196
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Re: WHAT IS A GOOD GENERATOR ??

Agreed, most 'Large Frame/ Case' Alternators are rated to a max RPM of 7-8,000. Indeed I noticed the Ecotech max was 8,000 continuous and 10,000 transient.

Yes I think once you start wanting more than 100ish Amps continuously, it's more realistic from a reliability and heat perspective to be looking at a Large Case unit.

This is basically the next tier up from standard small case alternators.

However, as already been discussed, it's not the only thing needing upgrading at these levels. Ideally multi ribbed drive belt etc.

However this is obviously also going to cost more for all this good stuff. They are also quite large and weighty. So you have to have the space around your engine in the bay etc

Where does it end?
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Old 13-11-2017, 18:30   #197
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Re: WHAT IS A GOOD GENERATOR ??

Well for me, not tied to propulsion engine, dedicated DC genny.

I'd ideally like something small and portable

does that automatically rule out diesel?

As an extreme example, of something completely different, for $150 https://www.homedepot.com/p/Sportsma...2085/300792167

but DC output

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Old 13-11-2017, 18:58   #198
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Re: WHAT IS A GOOD GENERATOR ??

A couple points:

1. Max alternator RPM - this varies. The Zena 150A I referenced earlier is rated OK up to 16,000 RPMs.

2. V-Belts - properly engineered, there is no problem with building a high output drive using v-belts. If you go to a v-belt website - Gates is a major manufacturer, you will find power ratings for the various size belts. The calculations are simple, and you can pick the size of belt you need. For our drives typically you will be using "A" or "B" size belts. If your power requirements exceed the rating for a single belt you use 2, or more.

As to horsepower required, 1 horsepower = 746 watts. You will need to multiply your watt output by a factor to account for generating inefficiency,
probably 1.3 is pesimistic enough.

I know of a V-Belt drive designed for aircraft use that transmitted about 60 hp thru a 10 belt drive. It was highly reliable, the Taiwan airforce used it as a trainer.

McMaster Carr has a number of multi-v belt pulleys available.
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Old 13-11-2017, 19:00   #199
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Re: WHAT IS A GOOD GENERATOR ??

You could look at the possibility of using an air cooled small diesel to run the dc generator head.
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Old 13-11-2017, 20:26   #200
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Re: WHAT IS A GOOD GENERATOR ??

Examples? Mind you "portable" I'm talking maybe 60lb

That micro Sportsman is 20lb including the alt , inverter, fuel tank the lot. The 40A charger with derating capabilities you'd also need probably weighs more.
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Old 13-11-2017, 20:28   #201
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Re: WHAT IS A GOOD GENERATOR ??

Quote:
Originally Posted by Pauls View Post
If your power requirements exceed the rating for a single belt you use 2, or more
…
I know of a V-Belt drive designed for aircraft use that transmitted about 60 hp thru a 10 belt drive.
Is there any advantage to fitting multiple vee belts over a single serpentine?
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Old 13-11-2017, 20:56   #202
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Re: WHAT IS A GOOD GENERATOR ??

Quote:
Originally Posted by a64pilot View Post

A serpentine belt greatly increases belt contact area, so does larger pulleys.
Decently large pulleys and a serpentine belt, and I’m sure you could pull hundreds of amps easily, and there seems to be no real life limit, no wear occurs from what I can tell, although eventually over years the belt will eventually deteriorate from age. Maybe a decade?
I fully agree.

We still need a reasonable supplier for pulleys. Those pulleys are made from round billet steel or aluminum and than processed with a high precision CNC machine.
Those are all standard sizes the same as the belts and they manufacture them like spagetties. Round billet is sold by the lbs and then there is a simple charge by time units.
There are manufacturers that are specialized and do nothing else then pulleys.
I estimate the big crankshaft pulley should cost around 50-60$ a piece if we find the right source and this is still expensive.
With a reasonable price it will be much easier for people to decide to convert to serpentine belt.
Today all automotive accessories are driven by serpentine belts.
They have to take multiple loads from alt, water pump, hydraulic brakes and stearing pump, AC compressor and what not ? and itīs all driven by one serpentine belt with a belt tentioner.
Since most of the marine engines come from industrial or agriculture engines we might even find those pulleys for peanuts in the junk yard.

Actually with the required production numbers a serpentine drive should be cheaper than a V belt drive.........

But as always we have to pay the bandits for the marine sticker
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Old 13-11-2017, 22:08   #203
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Re: WHAT IS A GOOD GENERATOR ??

Quote:
Originally Posted by Q Xopa View Post
Agreed, most 'Large Frame/ Case' Alternators are rated to a max RPM of 7-8,000. Indeed I noticed the Ecotech max was 8,000 continuous and 10,000 transient.

Yes I think once you start wanting more than 100ish Amps continuously, it's more realistic from a reliability and heat perspective to be looking at a Large Case unit.

This is basically the next tier up from standard small case alternators.

However, as already been discussed, it's not the only thing needing upgrading at these levels. Ideally multi ribbed drive belt etc.

However this is obviously also going to cost more for all this good stuff. They are also quite large and weighty. So you have to have the space around your engine in the bay etc

Where does it end?
Yes I am aware of all those facts like weight and quality and cost.
On the cheap I would simply use 1 Honda or 2.
There is also a similar brand made in the USA that cost half the price then a Honda and till now the feed back I have is happy customers.

Check it out

But I think here we want to talk about another dimension that we want to compare to the standard aproach of independants AC generator.
And specially in LFP that needs a new aproach in my point of view.
LFP is a game changer.
LFP due to the high amp discharge capacity is capable to handle loads that prior could only be handeled with AC generators.
This why I changed to look at a generator only as another component of the system.
It seems also some generator manufacturers are opening up to DC charging.
Here for example is http://polarpower.com/applications/marine/

They say:
The advantages of using a DC generator:
*Generator runtime is significantly reduced for comparable charge.
*A DC generator is smaller and lighter than a comparable AC generator.
*Less fuel is used in charging the battery.
*Best is dual with alternator 12v for house bank and generator for propulsion 5kw

The disadvantages of using an AC generator:
*The AC generator takes longer to charge the battery due to current limits in the inverter or battery charger.
*Adding additional inverters or battery chargers increases system cost and takes up space while adding weight.
*The conversion of AC to DC consumes more fuel due to power conversion losses in the inverter or battery charger.
*The AC generator is significantly larger and heavier than the DC generator.

Off course they are already focused on tomorrow and electric propulsion. But since they have huge power demands I would say the more their arguments are valid for us.
Obviously it is different designing a new system than converting an existing one but when we look closer we are already on the way.
Most boaters today try to have a good size solar system. The next step is LFP with more energy storing capacity and bigger consumers by using inverters. The only thing that is left to do is find a reliable DC source on the charging side to add on to solar.
From this point on itīs only a question to satisfy the individual demand of each boater.

Now back to Polar Power. They are focused on a boat with out main engine and all there is on the charging side is a generator. So they run the entire boat including propulsion with one engine.
Is it safe ?
Well a sail boat also has only one engine.
Is it safer with 2 engines ?
What happens if the main engine fails ?
Is the second engine of the gen make us live safer ?

So why not using the existing engine we already have and take max advantage with quality components instead of investing in buying more problems ?

I believe at this point some interesting points of view have crystalized when asking .... What is a GOOD generator ??

Yes, there are some details besides the basic components that have to be watched.... specially on the price side but I would say besides the costs of LFP that has nothing to do directly with the basic question of a good gen I can see already very clear my advantages.
I take 2 EcoTech alternators that will cost some 2000$ that produce a huge amount of charging capacity with very low maintanance issues. Letīs give it another 1000$ +/- and what more is there that costs money ?
Thatīs half the price of the typical AC gen with a lot less issues in all the aspects we analaysed till now.

Well letīs try and find the negative points of such a system.
I am still searching but I am kind of a handy man.
Of course for some itīs much simpler to go to the dealer and say I want an AC gen.
Yeah, that is a very negative point for some.
And if they can find a professional that can built them such a system we are talking about they get charged an arm and a leg.

What a petty
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Old 13-11-2017, 22:18   #204
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Re: WHAT IS A GOOD GENERATOR ??

Quote:
Originally Posted by Pauls View Post
A couple points:

1. Max alternator RPM - this varies. The Zena 150A I referenced earlier is rated OK up to 16,000 RPMs.

2. V-Belts - properly engineered, there is no problem with building a high output drive using v-belts. If you go to a v-belt website - Gates is a major manufacturer, you will find power ratings for the various size belts. The calculations are simple, and you can pick the size of belt you need. For our drives typically you will be using "A" or "B" size belts. If your power requirements exceed the rating for a single belt you use 2, or more.

As to horsepower required, 1 horsepower = 746 watts. You will need to multiply your watt output by a factor to account for generating inefficiency,
probably 1.3 is pesimistic enough.

I know of a V-Belt drive designed for aircraft use that transmitted about 60 hp thru a 10 belt drive. It was highly reliable, the Taiwan airforce used it as a trainer.

McMaster Carr has a number of multi-v belt pulleys available.

My personal opinion:

The Zena alternators with a properly sized V belt drive are good.

But honestly, the EcoTech alternator with a serpentine belt drive are way better in "any aspect".

Just compare the specs
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Old 13-11-2017, 22:19   #205
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Re: WHAT IS A GOOD GENERATOR ??

Not a full website, placeholders, broken links
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Old 13-11-2017, 22:26   #206
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Re: WHAT IS A GOOD GENERATOR ??

Quote:
Originally Posted by john61ct View Post
Well for me, not tied to propulsion engine, dedicated DC genny.

I'd ideally like something small and portable

does that automatically rule out diesel?

As an extreme example, of something completely different, for $150 https://www.homedepot.com/p/Sportsma...2085/300792167

but DC output

Science project proposals accepted
Haha science project
Off course from an economic point of view You canīt go wrong with this one.
Donīt bother and fix it
Buy a new one
Thatīs hard to beat
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Old 13-11-2017, 22:27   #207
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Re: WHAT IS A GOOD GENERATOR ??

Is there any advantage to fitting multiple vee belts over a single serpentine?

What you are calling serpentine is commonly called multi rib V belts. Serpentine is a method of belt routing, not a belt type. Multi rib belts are available in different sizes for transmitting different amounts of power.

Either multi ribs or regular v belts can do the same job. I think it comes down to what type of pulleys you can get for your application.

The multi rib belts have the advantage of being able to run on a smaller diameter pulley because they are quite thin. So you can build a higher ratio drive with them.

If both were commonly available I'd prefer the multi rib. Frequently, in the real world, v belt pulleys are more easily (cheaply) available.
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Old 13-11-2017, 22:53   #208
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Re: WHAT IS A GOOD GENERATOR ??

Yes pulleys can cost a lot.

Nothing to do with "marine" either.

I guess auto parts would be the logical hunting ground, find the right ones then try junkyards?
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Old 13-11-2017, 23:03   #209
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Re: WHAT IS A GOOD GENERATOR ??

Quote:
Originally Posted by ColdEh Marine View Post
He actually didn't build the regulator . He modified my existing one and added the adjustability. 13.8 volts is fine but with no tail current the batteries don't get full . I go to 14 volts and at that the batteries are still pulling 200 amps . No imbalances as yet , 3 years in at full service .

Regards John
Hi John
First of all a big THXs
I was not aware of those EcoTech alternators.
After reading the specs I am very pleased. They exceeded my rather conservative expectations. This is really a valid component for my thoughts.
There is this old saying.... a system is always as good as the weakest component.

Yes 3 years of service and no issues.Thatīs what I expect for that kind of money. It seems they care about their reputation and make no quality compromises.

As to Your commentary..... in the specs it says

* Factory adjustable voltage set point

So what did he modify ?

I like the 3 internal cooling fans. Since I donīt pretend to run this alternator at the limits I donīt expect any mayor headaches for a long time and in case something goes wrong with the second alternator the spare is already installed
I guess with LFP the optional voltage sensing is a good idea

You agree ?
Your direct drive is cool as the engine and alternator are a fair match
Unfortunatly I wonīt have the space. So I will have to go with serpentine belt drive. Will give a sligth advantage at low RPM. I think around 1000-1200 RPMs on the engine and the alternator 1800- 2000 RPM feels good to me
with the Westerbeke 30B.
Whatīs Your opinion ?

Remains to find a cheap source for the pulleys for the serpentine belt and thatīs it for a GOOD generator

Why do You want to use 2 alternators in Your new set up ?
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Old 13-11-2017, 23:09   #210
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Re: WHAT IS A GOOD GENERATOR ??

PS: Before I forget

The other day I watched a guy fabricating an engine mount for a second high output alternator on a car.
He used carbon fiber.

I hope I can find him again
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