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Old 15-07-2014, 21:47   #61
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Re: Highest Output Alternator

From someone who makes a living answering cruisers technical emails, let me divert this thread a little further and say this about technical questions and answers. In about 30-40% (possible more on Fridays and even up to 65% during a full moon) of the questions I'm asked I know half way into the question that they are asking the wrong question. It's not because I'm smarter than they are, it's just because in doing something for a living, you get the same questions literally hundreds and hundreds of times and you then start to learn where the question is coming from, where it is going and how best to answer it so that it doesn’t lead to another question.

Not to pick on you JoeFish, but since the 99% of us didn’t live up to your standards for internet advice and attention span, lets review.

Originally Posted by JoeFish View Post
I'm looking for a new alternator for our motor.
In a perfect world I'd like to find one that I can push a lot of amps into our house batteries quickly, as I sail on AP a lot and that tends to suck up about 50Ah a day plus all the other normal loads from radios, instruments, etc. (I'll admit we use far less in that department than some).
An suggestions for something high output?
Original engine was 16HP and we made hull speed with that. The new motor is a 26HP triple with a max prop so we have plenty of reserve to push a big alternator.
No mention of the most important issues in your question: Size of batter bank, type of battery bank, LiOn is a game changer and no we have no idea of the alt size range you are looking for. So we guess a little at first on just want you are asking for. Do you know that you will need more than a 1/2" V-belt for an alternator above 100A? heck...we don't know what you know or don't know???

Originally Posted by JoeFish View Post
Yes, we're switching to LiFePO4 now so this is the time to get a high output alternator. I've never really understood if an alternator's load on the engine increases if it has demand on it or not, that has me considering what the happy medium is as we can end up motoring a lot if we're on the back side of Vancouver Island.
Got it now, you are converting to cutting edge marine technology but at the same time make a comment about not understanding the general basics of how alternators work vs load and Hp. So right away all of us are thinking along these lines: does he know the basics or do we back up and do a battery charging and alternator school 101 series webinar for free for him? Do we risk giving technical info without a background basic understanding and then cause him more problems with a technical questions he doesn't understand? This is a huge risk in giving someone that doesn'tunderstand something 3/4 of the technical informaiton when the other 1/4 can cause a fire with their LiOn batteries!

Originally Posted by JoeFish View Post
125A is not what I'd consider high output these days for charging LiFeYPO4 banks. 200 outputting 160 would be about the least output I'm looking for.
Well how would WE know what you consider HO our not? Work with us here….

Originally Posted by JoeFish View Post
Actually, MaineSail seems to be the only one paying attention. His two comments in the last three pages have 99% of the useful information in this thread.
Mainsail has a great way of cutting through the crap, fog, questions and misdirections asked by clients and free info seekers on the web. If you have spent any time on the LiOn threads where people try to literally kick his ass and question his manhood for not giving them the answer THEY WANT but rather giving them the answers THEY NEED you would understand a bit that MainSail easily qualifies for Internet Free Advice Sainthood. The great thing about internet chat room Q&A is that you are absolutely going to get responses from people who approach not just the answer but your very question from a totally different point of view. Is this a racing boat, a cruising boat, do you anchor more than motor around? Will you have a generator and not even need the alternator on the engine anway? ****...all of that info goes into being able to give you the best answer regardless of what question you asked. If you ask the wrong question, you get the wrong answer. Some like the diversity of thought and answering styles and can wade through the tall grass…others think the guy screaming grass fire on the Serengeti isn’t paying attention.

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Old 15-07-2014, 22:43   #62
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Re: Highest Output Alternator

Good Post, Rich! I hope that the OP and other potential posters read it with consideration and then try to frame their questions more helpfully. And for those who just can't do that, perhaps not get peeved when they don't get the answer they want or think they want.



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Old 15-07-2014, 23:04   #63
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Re: Highest Output Alternator

The critical data: L26 3 cylinder diesel, so we're HP limited in our ability to drive a big alternator. How far can we go? I don't know yet as we've only had a very small alternator on it that's not going to be much use pushing a lot of amps, my guess is 220 may be the limit given what our engine guys have told us.

The pulleys are already set up to use serpentine belts, not whimpy v-belts. A big alternator has been in the plan book all along.

The total bank size will be 360Ah. We sail more than motor, and the AP is the hungry child in this equation. It eats more than everything else on the boat together, including instruments, refer & lighting combined. Systems on the boat aren't really all that complex.

Objective is to reduce charge time to a minimum as long range cruising in the NW up through SE Alaska puts us out of range of fuel for weeks. Our small 36Gal tank puts a crimp on running it to charge many hours every couple days. When the wind dies out we need fuel in reserve to motor. High acceptance rate means we get very good charge efficiency out of every drop of fuel burned.

LiFePO4 because it gives more total usable Ah with usable voltage without having to put 800Ah worth of lead cells on board which would seriously re-trim the boat and there aren't many places to store a bank like that on board.

Third day, you seem to be under the impression I was busting Maine's balls, and nothing could be farther from the truth, in fact I am one of his paying customers and take his advice to heart; your comment about sainthood is dead on. RC suggested Balmar, a brand I have had some serious problems with in the past, so I'm looking for good alternatives to that suggestion.

Did I leave anything out?
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Old 15-07-2014, 23:08   #64
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Re: Highest Output Alternator

Originally Posted by Ex-Calif View Post
I think you may have stumbled into the "free" internet.

You probably want the "pay for use" internet where people can read your mind, and all the advice exactly matches what you want.

If you want perfect answers try writing perfect questions. This is like the dance of the seven veils - we get one parameter at a time as we keep failing to meet your expectations for a perfect answer.

Now we know the answer can't be Balmar... Oh and that Fitzall alternator you asked about on page one? Why don't you install one and let us all know how it works.

Honestly - I didn't see any bad customer reviews (at least on the free internet) except one dude who had a hissy fit about a return issue. They do seem to be aimed at the automotive market and think that painting it gray is all it takes to marinize it. Butcha prolly knew that from you own google search...

In the meantime it's OK to keep throwing rocks at all the free opinion and advice. No one really takes the free internet seriously anyway.
Actually I think we take it very seriously, because it is extremely useful, and often fun, too.

The main thing is to understand how it works. It is absolutely NOT just a free tech support system where one person, the OP, asks a question, and a bunch of people do nothing but answer that narrow question. It's an open discussion, and the original question stimulates other thoughts and other questions. In this case, a lot of interesting general discussion of high output alternators ensued, plus some general discussion of LiFEPo batteries, and so forth. This -- thread drift -- is completely normal, and it's not right for the OP to get impatient with it. And in general it's not cool to show impatience towards people who are mostly just trying to help.

The other essential thing to understand when asking a question on here is that the quality of the answers usually varies tremendously. Some people who answer are real pros (like MaineSail) with a wealth of accurate knowledge. Other people (like me) are amateur dabblers, who might say something useful, but might just as well say something stupid. You have to be able to sift through all the info and figure out how to separate the wheat from the chaff. That's also completely normal.
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Old 16-07-2014, 01:39   #65
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Re: Highest Output Alternator

Originally Posted by JoeFish View Post
Third day, you seem to be under the impression I was busting Maine's balls, and nothing could be farther from the truth, in fact I am one of his paying customers and take his advice to heart; your comment about sainthood is dead on. RC suggested Balmar, a brand I have had some serious problems with in the past, so I'm looking for good alternatives to that suggestion.

Did I leave anything out?
Yes, you did.
Why you just didn't ask him in the first place if you are one of his paying customers and take his advice to heart.
He is probably in the best position to give you advice isn't he?

As you said, you wanted a big output alternator for your 30hp motor.
Why don't you get a 200+A large frame alternator as has been advised on here and then pay Main Sail to install it.
I am sure that would make him happy.
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Old 16-07-2014, 02:29   #66
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Re: Highest Output Alternator

I don't have any issue with the way questions are asked. I also have spent my career in the technical field - jet airplanes - and if you can 'splain stuff to pilots, you can 'splain it to anyone.

And I totally agree the dialog created, even the supposedly dumb comments often open up avenues for everyone to learn. Now thread drift that hijacks the OPs ability to get answers is rude, but if one is talking the same topic one can advance the dialog in many ways.

The fact that CF attracts boating professionals is magic! However, everyone puts their pants on one leg at a time and challenging an "expert" is usually never a problem for an expert, because the expert stays an expert by learning new things every day...

We now return to your regularly scheduled internet...

- 26 hp engine
- maximize amps produced in the minimum time because fuel is limited
- minimize battery bank to 360 if possible because space is limited.
- Go for LiFePo4 because acceptance rates are high
- minimize cost

One thing that went by pretty quick was Hud3's idea about taking the alternator off-line when max engine power was needed to propel the boat.

In theory that could maximize HP available to drive the alternator.

I'm similar to Dockhead - I ain't smart on all this stuff but I'm smart enough to prompt the conversation along.

The really smart sparky's (like MS) are getting smarter and smarter at this but are also aa bit in the theoretical world as to how they'll work long term (my opinion) - And the unsaid but implied thing that RIch said was - If a guy like MS gives you advice, he is staking his reputation (which is way more valuable than mine) so he will tell you what he "knows" will work.

If you go off the paved road you are a trailblazer - the world needs those folks too. many many folks come to CF shopping for an answer and validation of their plan - It doesn't always work out and often ends in drama.
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Old 16-07-2014, 05:22   #67
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Re: Highest Output Alternator

To really make this work and work well, ain't going to be cheap.

1. with only 26HP to work with a large Alt is going to pull a considerable amount of the available HP, so if you correctly prop the engine for operation when the Alt is pulling it's max amps, it will be seriously underpropped when the Alt isn't working very hard, if you prop the engine for no load on the ALt, then you'll be lugging it when using the alt hard.
2. so maybe when driving the Alt hard have the engine in neutral or have a variable pitch prop (note, I have no idea of the existence or availability of such a prop)
3. look maybe at a generator and save your main engine and all the problems associated with putting a big alt on a little engine like side loads on the crank, adequate cooling for the alt etc. Everyone loves to hate the little Honda's, but at slightly less than $1,000 ea. they answer the lotta power for little money question. They are around 110 amps at 14 V I believe.
4. There are no perfect answers, gotta pick one that you like the best, but I think this is a matter of either your gonna pay for the best answer, or pick a less expensive answer that you can live with
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Old 16-07-2014, 06:30   #68
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Re: Highest Output Alternator

Does anybody just add a second, cheap normal alternator (on a separate belt opposite the other alternator) if they want more capacity?

Seems like it could eliminate a few problems such as side loading of the crank bearing. One would also have redundancy.

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Old 16-07-2014, 10:29   #69
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Re: Highest Output Alternator

I routinely see 100 amps out of the 115 amp stock alternator on my Volvo D1-30, even when just running tests at the dock.
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Old 16-07-2014, 13:01   #70
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Re: Highest Output Alternator

For the OP, given all of the above, the next question would be how old is your autopilot and why is it using that much power? Fine tuning the parameters, switching to a more efficient electric motor or getting a whole new AP may be cheaper and work better in the long run.

For everyone else:
OPEN 60 REFIT: Great American IV Ready to Sail

How fast do you want to charge?
How much money have you got?

I remember seeing a similar Yanmar inline alternator a few years ago but can't find any reference to it anywhere now. Does anybody remember those?
It would seem their time has come if Yanmar could be talked into resurrecting them.
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Old 16-07-2014, 18:21   #71
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Re: Highest Output Alternator

Originally Posted by sy_gilana View Post
I am sure someone is going to knock up a BMS using an Arduino board soon. I would use a PLC to make my own BMS.
I totally agree about the plc part. I recently completed the plc component of my electrical instrumentation course. I might draw up the processes and give the programming a try. I currently don't have access to a boat so will have to test it on a simulator for now.
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Old 17-07-2014, 09:55   #72
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Re: Highest Output Alternator

Originally Posted by buzzardsbay105 View Post
For the OP, given all of the above, the next question would be how old is your autopilot and why is it using that much power? Fine tuning the parameters, switching to a more efficient electric motor or getting a whole new AP may be cheaper and work better in the long run.
50A/day for an autopilot is very good - an average of 2A continuous. Be difficult to beat that - the clutch usually draws up to an amp itself.


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Old 26-07-2014, 08:14   #73
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Re: Highest output alternator

Originally Posted by Dockhead View Post
As others have said -- there is no point in an alternator too big for your battery bank. I think about 20% to 25% ratio of nominal alternator power to nominal bank capacity should be about right. Remember, that nominal rated power is rarely achieved, only at high revs, low temperature, etc.

Remember also that there is a huge difference between "hot-rated" alternators -- designed to produce high power levels continuously -- and car-type alternators which are just made for topping up batteries and running on-board loads, not producing large amounts of power. "Hot-rated" alternators are made for school busses and emergency vehicles under brands like Prestolite and Leece-Neville. Balmar don't make their own alternators and I think Balmar-branded alternators are a waste of money.

Remember that school-bus alternators usually require double belts (or maybe a serpentine). It's important to get the the drive system right. It can be expensive since you will likely have to change the pully on the engine and have a special bracket made, but it's really worth it.

And don't forget about external regulation. You will want to use one of the various multistage external regulators.

I have 110 amps by 24v (like 220 x 12v), a Leece-Neville as originally installed on my boat. I just added an Adverc external regulator to it. It charges a 420 amp/hours x 24v domestic bank and does a very good job. There is always abundant power when the main engine is running, and we always arrive with fully charged batts even if we motored for a relatively short time. I think it really makes sense to get this right.
Sounds like almost exactly what I am looking to do for my system. I currently have 440 amp/hours x 24v for the house bank. The standard alternator which came with the engine is a 35amp x 24v alternator with a single 3/8 inch belt. It has not been a problem as I can charge at 150 amps x 24v off the generator using the inverter (I limit the inverter to 100 amps and there are almost always other loads so I don't see over 0.2C) but the charger is capable of 200 amps @ 24v.

What I am interested in is the belt configuration you are running. My engine is a Perkins M90 (basically a 4-236) which is a slow turner (nominal cruise is 1700 - 1800 RPM.
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Old 26-07-2014, 09:49   #74
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Re: Highest output alternator

Originally Posted by Stu Jackson View Post

1 doesn't work because of 2.

Important Reminder:

Once you do ... these changes (AO to house bank), make sure that the BATTERY SENSE wire from your regulator goes to your house bank. The instructions with external regulators gives you an option to connect it to the back of the alternator. This will NOT work, since it will be reading almost if not more than a volt LESS than if it was properly placed at your house bank.

I see this all the time on our boat (100A alternator, MC-612 regulator, Link 2000). When the microwave turns on, the charging output goes right up BECAUSE of the battery sense wiring, which is NECESSARY to make the SYSTEM work properly.
The only reason you should have a different voltage at different ends of the same wire is when the amps on the wire are significant relative to the size (resistance) of the wire, i.e smaller wire has bigger resistance to bigger amps. This is called voltage drop. A big voltage drop implies too much current for the size of wire. A tiny, tiny wire can show full voltage to a voltmeter (no current on it) at both ends of the wire. Put a big load on it and the voltage drop is big. The only way ammeter shunts work for large loads is that they measure millivolt changes across the shunt. I guess I could be overlooking something here but it's pretty basic electrical physics - Ohm's Law.
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Old 26-07-2014, 11:40   #75
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Re: Highest Output Alternator

Do not know if this will help because I use LA. I have two 2800JB L-N alt on opposite sides of the engine (4-236) so less load on the crank bearings. Way less money than what you guys are talking about but then I have lots of room. Built the mounts myself back when I had a welder etc at home. I have an Ample Power reg one for both alt but a spare on board. 440 amp-hr T-105. 325 watt solar panels and an Air Breeze wind gen. Works well for me without the "Honda" solution. I have micro wave, computers, refer, etc and use about 80 or 100+ amp-hrs a day. My autopilot is efficient and I have no problem off shore as other things are not running. I have used this for several years now. I am now in Grenada and it works well but of course this is the trade winds. BTW I would like to have a larger crank pully as soon as I find a machine shop out here I like. I too am waiting until LiPo is more mainstream. One comment based on my experience worry more about solar and wind and size them as big as you can. You anchor more than motor out here and diesel cost a lot.. Hope it helps.

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