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Old 12-11-2017, 20:31   #181
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Re: WHAT IS A GOOD GENERATOR ??

OK, I'm not aware of the carrying capacity of dual vee, I was talking single vee. I do know it's less than poly-vee serpentine, so if retro-fitting from single that's my choice.

Note that emergency vehicles are carrying loads from the alt with a running engine, not charging a well-depleted LFP bank, so the 200A rated alt would rarely be actually producing even near that for long.

Finally, I've worked with big old Listers started by hand-cranking, and I know even in the peak of my youth, my arm didn't push any appreciable fraction of a horse's power.

Much less 28 of them 8-)
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Old 12-11-2017, 20:32   #182
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Re: WHAT IS A GOOD GENERATOR ??

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The alt specs will give a high range.

Guideline I've always seen and heard is no more than 80-90% of max output for any extended period.

But the point I brought up before

that the alt can spin with field current off, no load,

since my case, dedicated gennie engine, was no good for burning carbon

But your propulsion is loading up the high rpm, so with field current shut off at high rpm, I bet you can spin closer to the max rated rpm all day.

If the high vs low rpm difference is too small.

Some people also have a mechanical disconnect at the pulley tensioner.
Sorry, my reply comes a little late......my boss kept me busy

The alt can spin with field current off and no load ?
In my case with trying to use the main engine the RPM range of the alt is a big problem.
I certainly want to charge while I am motoring and when I am not I want high idling RPM.
As the RPM range of the alt is most likely smaller than the RPM range of the engine it will be impossible to stay on a max 80-90% of the alt rating.

However the field current shut off might offer an interesting choice.
I am going back to ColdEH Marine and his idea of the new installation with 2 EcoTech alternators.

And why not using 2 alternators with different sixes of pulleys.
One is geared optimum for low idle RPM that shuts of the field current when the RPM gets to high
The other one is geared to ca 80% at cruising speed and 100% at max RPM.....+/- ?

Of course this way I never get max charging capacity but in the case of the EcoTech I would say I get a very solid 250 Amp all the time and at high idle I will get some at 350 - 400 Amp
That is conservative and a lot less then 550 Amp but I could live with that
Both alternators stay in a very healthy range in every aspect while the whole RPM spectrum is sufficiently covered. No important temperature issues. That will results in less complicated regulating devices for max efficiency and less sensitivity to failure

I get the added benefit of my spare alternator already installed as a back up.
The weight and space savings are substantial.
I only have to maintain 1 engine

The costs with 2 Eco Tech alternators will be a lot less than with a separate engine or generator.

Looks like a very solid and reliable DC charging source to me.
Of course the proper size of the pulleys is essential.

Well, maybe ColdEH Marine can step in to get the info from EcoTech.

Of course they gonna like it but maybe this concept for a DC charging source by alternator can also by applied to other brands of alternators

In my point of view it remains to be seen what is the best idle RPM for the engine. Till now the only info from EcoTech is 1800 RPM for optimum effeciency as a standard
But what is their range of RPM they can hold those efficiency parameters ?
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Old 12-11-2017, 20:42   #183
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Re: WHAT IS A GOOD GENERATOR ??

Plus you would get redundancy.

KISS it's not though. I would think alt rpm set to 1800 as "productive idling", up to 6-7000 while under way would be plenty, just remove the load (cut field current) before the point where you think rpm's are too high.

Optimum rpm for the engine is of course dependent on the model engine, varies crazy widely. And completely independent of what the alt wants.

I would not care about marginal efficiency much myself, engine longevity is far more important. And noise/vibration issues, my personal fixation, so I need to vary between the two rpm even with the engine doing nothing but charging House bank.
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Old 12-11-2017, 21:54   #184
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Re: WHAT IS A GOOD GENERATOR ??

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Plus you would get redundancy.

KISS it's not though. I would think alt rpm set to 1800 as "productive idling", up to 6-7000 while under way would be plenty, just remove the load (cut field current) before the point where you think rpm's are too high.

Optimum rpm for the engine is of course dependent on the model engine, varies crazy widely. And completely independent of what the alt wants.

I would not care about marginal efficiency much myself, engine longevity is far more important. And noise/vibration issues, my personal fixation, so I need to vary between the two rpm even with the engine doing nothing but charging House bank.
Energy redundancy is comfort
With this concept of 600 W solar 8-1000 Amp LFP and 2 EcoTech run time for charging should be low even with running an AC.
I calculate once the boat is cooled down and than with the AC on low and a full LFP it should be no big problem to spend a comfortable night without stress on the LFP even so there are other consumers.

Next on the list noise and vibration.Usually those two parameters live close together. On a 3 cyl engine 1000-1200 should be fine. ))) Letīs see if I can go lower.. I hope so
With the Westerbeke 30B optimum torque is between 2000 - 2500 RPM with max 3700.
Cruising is 2700 at 6-7 knots. Thatīs good enough for me
I am not worried about any carbon built up. When I motor the engine gets hot and I will blow out any built up. If not a little H2O will solve the problem. I might do that anyway because it also produces cleaner exhaust gases and will take away the diesel smell.

Remains a little more stress on the bearings of the engine while idling.
Well, since I only play with one engine I better take good care of the baby to make it last. If I get a 5% less engine hours I am happy compared to all the other benefits. An extra 40 Lbs each alternator is not of importance.
What I like about this set up is the ease of installation and no big changes on the boat due to a separate gen set.The LFP is also very compact and the solar is more or less a one time and forget it.

Did I forget something ?
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Old 12-11-2017, 22:27   #185
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Re: WHAT IS A GOOD GENERATOR ??

Maybe don't bother with the solar if motor runs a little every day anyway
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Old 13-11-2017, 06:32   #186
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Re: WHAT IS A GOOD GENERATOR ??

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I would also hold at 13,8 Volt but it seems this guy is smart if he can built a regulator with adjustable voltage for 50$.

Obviously he does not make his money selling regulators like others.

I always like the regulators that are not OVER regulated.

Most likely they are easier to fix.


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
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Old 13-11-2017, 10:42   #187
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WHAT IS A GOOD GENERATOR ??

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interesting part for me is my motor is started with a dynostarter and dual vee belt.

The dual vee seems to handle the torque needed to turn my engine over.


It does so likely due to the size of the pulley.
You could like Nexgen does size the pulleys large, the large size of course means way more belt is in contact, and that is what limits belt power absorption, the friction between the belt and the pulley, not the strength of the belt.
A serpentine belt greatly increases belt contact area, so does larger pulleys.
Decently large pulleys and a serpentine belt, and Iím 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?
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Old 13-11-2017, 11:02   #188
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WHAT IS A GOOD GENERATOR ??

Oh, and Alternator RPM limits are mechanical, they donít care I donít believe whether they are making power or not.
But most alternator RPM limits are pretty darn high, in my opinion almost all Marine alternators are underdriven, cause we just use regular automotive pulleys, and for instance at highway speed my Miata runs a continuous RPM of 4000, and will turn 7,000 RPM, nether of which is possible with my Yanmar, but if you look, pulley diameters are very similar.
Depending on make etc, you will find most automotive alternators can be run continuously from 16,000 to 18,000 RPM, and I do not think any of us have 10 to 1 ratios on our alternators or even close.
http://www.paperformance.com/rpm-calculator/

If you turn an alternator close to its RPM limit during high output, it will run much cooler as its fans are moving much more air and its field current can be lower to make the same power at high RPM, lowering the RPM of an alternator is exactly opposite of what you want to do if your wanting high power like to charge a Life-Po bank.
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Old 13-11-2017, 11:05   #189
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Re: WHAT IS A GOOD GENERATOR ??

Someone got a good deal

https://m.ebay.com/itm/NIB-NEW-Eco-T...s/162353924966

Next ones won't be that cheap
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Old 13-11-2017, 11:07   #190
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Re: WHAT IS A GOOD GENERATOR ??

Quote:
Originally Posted by a64pilot View Post
It does so likely due to the size of the pulley.
You could like Nexgen does size the pulleys large, the large size of course means way more belt is in contact, and that is what limits belt power absorption, the friction between the belt and the pulley, not the strength of the belt.
A serpentine belt greatly increases belt contact area, so does larger pulleys.
Decently large pulleys and a serpentine belt, and Iím 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?
the biggest enemy of a serpentine belt is flexion with age and heat. Auto makers recommend belt change every x miles or 2 years.
For my install it would take to much to convert to serpentine. It is setup for vee now. ( mounts are there but no alternator ) if you have the space then definitely convert to serpentine.
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Old 13-11-2017, 12:42   #191
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Re: WHAT IS A GOOD GENERATOR ??

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Sorry, my reply comes a little late......my boss kept me busy

The alt can spin with field current off and no load ?
In my case with trying to use the main engine the RPM range of the alt is a big problem.
I certainly want to charge while I am motoring and when I am not I want high idling RPM.
As the RPM range of the alt is most likely smaller than the RPM range of the engine it will be impossible to stay on a max 80-90% of the alt rating.

However the field current shut off might offer an interesting choice.
I am going back to ColdEH Marine and his idea of the new installation with 2 EcoTech alternators.

And why not using 2 alternators with different sixes of pulleys.
One is geared optimum for low idle RPM that shuts of the field current when the RPM gets to high
The other one is geared to ca 80% at cruising speed and 100% at max RPM.....+/- ?

Of course this way I never get max charging capacity but in the case of the EcoTech I would say I get a very solid 250 Amp all the time and at high idle I will get some at 350 - 400 Amp
That is conservative and a lot less then 550 Amp but I could live with that
Both alternators stay in a very healthy range in every aspect while the whole RPM spectrum is sufficiently covered. No important temperature issues. That will results in less complicated regulating devices for max efficiency and less sensitivity to failure

I get the added benefit of my spare alternator already installed as a back up.
The weight and space savings are substantial.
I only have to maintain 1 engine

The costs with 2 Eco Tech alternators will be a lot less than with a separate engine or generator.

Looks like a very solid and reliable DC charging source to me.
Of course the proper size of the pulleys is essential.

Well, maybe ColdEH Marine can step in to get the info from EcoTech.

Of course they gonna like it but maybe this concept for a DC charging source by alternator can also by applied to other brands of alternators

In my point of view it remains to be seen what is the best idle RPM for the engine. Till now the only info from EcoTech is 1800 RPM for optimum effeciency as a standard
But what is their range of RPM they can hold those efficiency parameters ?

This is the specifications of the Eco-Tech alternator and power graphs .

http://www.ecotechalternators.com/wp...t-14V.pdf_.pdf

Regards John.
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Old 13-11-2017, 13:23   #192
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Re: WHAT IS A GOOD GENERATOR ??

When a belt is mission critical, e.g. engine cooling then proactive early replacement is justified.

For just charging your battery, buy top quality and carry spares.
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Old 13-11-2017, 13:27   #193
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Re: WHAT IS A GOOD GENERATOR ??

So choosing max alt rpm at 6-7000 should give plenty of flexibility on a propulsion engine

in order to set the lowest possible (determined by min torque to push 200+A actual load) engine "productive idle" rpm

Right?
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Old 13-11-2017, 15:25   #194
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WHAT IS A GOOD GENERATOR ??

If possible Iíd gear an alternator to run around 6000 RPM at cruising RPM, so that even doubling it to 12,000 still doesnít get you anywhere near RPM max, or better yet make it so your engine at max RPM maxes out the alternator RPM, how often and for how long do you run at full RPM? For me the answer is never, cause Iím a little over propped, only way Iím getting to 3600 RPM is reverse or neutral.
However without a layshaft or similar, I donít think you can gear one that high as we are looking at say a 12Ē crank pulley and a 2.5Ē Alternator pulley to get to a 5 to 1 ratio, and who can do that? Only way I see is fit a lay shaft with four pulleys total and two belts, with four pulleys total, go 2.5 to 1 on the first and 2.5 to 1 on the second to get to the final 5 to 1.

The reason to spin them fast is to get the cooling, a small frame alternator at normal RPM on our boats canít make much if any more that 100 amps continuously, even if itís a 200 amp alternator, it has to cut back due to heat or burn up.

However with a school bus alternator or a Military one then you donít have to turn them so fast, but the Military one is as big as a small Diesel, no way most can mount on in the engine compt.
However if memory serves the power output is monstrous, as in hundreds of amps, at 28V, so about four times wha the biggest Balmar claims.
I think they may be 10KW or so, but huge and heavy.
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Old 13-11-2017, 15:41   #195
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Re: WHAT IS A GOOD GENERATOR ??

I don't know of any small-frame I'd use for LFP, even 60-80A. Maybe with external forced ventilation like Porsche does?

Most high-output large-frame alts aren't **that** big, ship them normal USPS all the time.

No way you want to spin at 12K
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