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Old 01-03-2015, 11:02   #1
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Most practical way to upgrade Yanmar alternator?

Hello everyone.

I am trying to figure out what is the most reasonable way to upgrade the 80A Hitachi alternators that you find on Moorings monohulls with 3YM20 Yanmars.

I have read plenty of good stuff by Maine Sail , Dockhead and others and now need to translate it to "the" solution for my little piece of French plastic.

I need your help!

Desirable features of the solution (most important first)are:
  1. get rid of the "temperature" protection that dials down the current or voltage when the regulator/alternator gets too hot and makes the thing run for ever at 13.5V without charging the batteries much.
  2. ability to adjust absorption voltage at about 14.4V sensed at the battery (vs sensed at the alternator). It is not necessary to have temperature sensor and compensate voltage based on that.
  3. minimal work in making mounts, brackets, etc to adapt alternators with different shapes .
  4. will not exceed recommended loads on the pulley bearings
  5. A bit more bulk current than the 80A we have right now, but this is not critical. The house bank is comprised of one 8D Lifeline AGM rated at about 200Ah. Therefore it can take more than 80A early on but not for very long.

I do NOT need 3-stage charging. There is always wind in the Caribbean and when the batteries are fully charged I can just stop the engine.

I do not need fancy brand names; just something that works better than the usual Hitachi bareboat setup that will kill batteries in a season and a half.

I am all ears!
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Old 01-03-2015, 11:46   #2
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Re: Most practical way to upgrade Yanmar alternator?

My humble suggestion is that you do need three stage charging to not destroy your battery. Cheap and reliable seldom go hand in hand, but your best bet may to have a field tap wire installed on your existing alternator, then buy any of the many external regulators made with batt voltage sensing. Install the regulator and then de-rate the alternator to prevent it from burning up and charge away.


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Old 01-03-2015, 11:58   #3
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Re: Most practical way to upgrade Yanmar alternator?

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Originally Posted by Sailmonkey View Post
My humble suggestion is that you do need three stage charging to not destroy your battery.
Thanks. Regulation is not really my problem. There are plenty of cheap external regs out there. I can easily "add" a lower voltage third stage by inserting a diode and a switch or a timer. That will only be necessary for a long motorsail such as BVI to SXM. By the way, in my experience flooded and AGM batteries can take 14.2V almost for ever. My old Honda CR-V runs at 14.4V all the time and batteries last 4 years..

At this time I need cost-effective options to get an alternator that can run flat out at 80 or 100a without burning or dialing down voltage, AND will fit the 3.15 inch mount...I am sure this has been done before... I am happy to pay more than Hitachi price but not yet ready to fork US$500 for a Mark Grasser or Balmar unit. I would very much prefer some 100% duty rate alternator fo commercial use that is not sold as "marine" product..
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Old 01-03-2015, 12:41   #4
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Re: Most practical way to upgrade Yanmar alternator?

1/2 price of a Balmar, from ABI
Yanmar, Perkins & Many Small Diesel Auxillary Engs. 12V 120-Amp with a 3-1/4" Saddle Mount, Internal | API Marine Inc
Yanmar, Perkins & Many Small Diesel Auxillary Engs. 12V 94-Amp with a 3-1/4" Saddle Mount | API Marine Inc
I have no idea how well /how long they work at high load. They don't seem to have as fancy air-cooling as the Balmars.

Maybe other can share experience with ABI Marine alternators?

Dirk
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Old 01-03-2015, 15:02   #5
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Re: Most practical way to upgrade Yanmar alternator?

"Desirable features...get rid of the "temperature" protection "
I would disagree vehemently. Every alternator contains tightly wound wire coils, and a diode frame. Those coils are lightly insulated ("varnished") and if you overheat them, the coils expand and find things to scrape and short out on. Or, the insulation breaks down, with dramatic results.
And the diodes? All have power ratings (that's the basic power rating of the alternator) and those are based on how much HEAT is being generated versus how hot they can get before breaking down and permanently failing.
Taking out the thermal protection is like taking the fuses out of your fuse box and saying you can safely replace them with pennies. By all means, go ahead. It will be an expensive lesson.
The trick is, keep the thermal protection, but build a system so well that it never has to kick in unless, say, it is 110F outside and your engine compartment is hitting 170F and you really need full alternator power at all costs.

"ability to adjust absorption voltage at about 14.4V sensed at the battery (vs sensed at the alternator). "
Two separate issues, one is adjustable voltage. The other is voltage sensing. Almost all regulators (or alternators with integral regulators) can be configured as "1-wire" or "3-wire". The former has the voltage sense lead tied back at the alternator, so it doesn't have to be switched when you switch battery banks. ALL of them can be reconnected as "3 wire" (auto industry style) but if you fail to keep voltage on that sense lead, almost all alternators will burn out in a flame of glory in 30 seconds at the most.
So install proper switching, or convert to one battery bank, and don't let that happen.

"It is not necessary to have temperature sensor and compensate voltage based on that." OK, as long as you're aware that temperature compensation AT ALL TIMES is essential for proper long battery life. You could monitor and adjust that manually...what a nuisance...or ignore it and pay more in new batteries than the compensation costs.

"minimal work in making mounts, brackets, etc to adapt alternators with different shapes"
Well, then you find out the frame size, the diameter of the body of your Hitachi, and you buy the most powerful Hitachi with the same identical frame size. That will put the pulley in the same place, the mounts in the same place, and all you'll need is the extra length to accommodate a longer alternator. Some series are 50-60-65-70-80A, others go up to 130A. But once you change the frame series, or the alternator type, all bets are off.
If the optimum speed, maximum speed, minimum speed, are different (as they will be) from one alternator to another, you will NEED a custom pulley to optimize the output, which can cut your run time in half. Or, you may luck out and find what you need is available for that pulley. There's a thousand models out there, if you pick a slow day a good shop will say "Let's seewhat we got..." and browse the shelves for something close to start with.

"will not exceed recommended loads on the pulley bearings"
Hehheh. First you'd have to find out what those were.

"A bit more bulk current than the 80A we have right now, but this is not critical." Well, if you don't need more current, you just need proper external regulation, plus a cooler alternator with higher sustained duty capacity. So you look for the same frame series, maximum amp rating, and then you look for ways to keep it cool. Like two fans (at both ends) and some big heat sinks. And ducting in cooler air specifically ON the alternator. Some folks use blowers for this.

"The house bank is comprised of one 8D Lifeline AGM rated at about 200Ah. Therefore it can take more than 80A early on but not for very long." Depends on who you talk to. What it "can take" is not what is optimum for it. Most battery makers will tell you that once you exceed 25%C for a charging rate, you will reduce battery life. That would be 50A for your battery.

"I do NOT need 3-stage charging. " No, but again, your battery maker will tell you that you are going to pay for this with shorter battery life. You want at least two-stage charging.

Maybe you don't want to reconsider the list of wants, but it sure seems like you're hellbent on charging that battery and running that alternator contrary to how all the pros in the business would say to do it.
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Old 02-03-2015, 07:15   #6
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Re: Most practical way to upgrade Yanmar alternator?

Quote:
Originally Posted by LeaseOnLife View Post
1/2 price of a Balmar, from ABI
Yanmar, Perkins & Many Small Diesel Auxillary Engs. 12V 120-Amp with a 3-1/4" Saddle Mount, Internal | API Marine Inc
Yanmar, Perkins & Many Small Diesel Auxillary Engs. 12V 94-Amp with a 3-1/4" Saddle Mount | API Marine Inc
I have no idea how well /how long they work at high load. They don't seem to have as fancy air-cooling as the Balmars.

Maybe other can share experience with ABI Marine alternators?

Dirk
I have been in contact with ABI. Their alternators are not hot-rated; they are not suitable for running for a couple of hours at rated current. I give them the honesty award for saying that up front!
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Old 02-03-2015, 07:27   #7
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Re: Most practical way to upgrade Yanmar alternator?

Quote:
Originally Posted by hellosailor View Post
"Desirable features...get rid of the "temperature" protection "
I would disagree vehemently. Every alternator contains tightly wound wire coils, and a diode frame. Those coils are lightly insulated ("varnished") and if you overheat them, the coils expand and find things to scrape and short out on. Or, the insulation breaks down, with dramatic results.
And the diodes? All have power ratings (that's the basic power rating of the alternator) and those are based on how much HEAT is being generated versus how hot they can get before breaking down and permanently failing.
Taking out the thermal protection is like taking the fuses out of your fuse box and saying you can safely replace them with pennies. By all means, go ahead. It will be an expensive lesson.
The trick is, keep the thermal protection, but build a system so well that it never has to kick in unless, say, it is 110F outside and your engine compartment is hitting 170F and you really need full alternator power at all costs.
I am sorry for leading to confusion. I am not looking for ways to remove the temperature protection of the stock alternator. I am looking for an alternator that will either run cooler or will withstand higher temperatures and comes with 3.15-inch spacing.There are plenty of such alternators from Balmar. I am just looking for a cheaper source of "hot rated" or "KKK" alternators that will fit the Yanmar 3.15 inch mount. Do you have any ideas?
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Old 02-03-2015, 07:32   #8
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Re: Most practical way to upgrade Yanmar alternator?

My gut feeling is if you just make sure your current Alt has a dedicated supply of cool air,
Given your current Battery bank size, you don't need to do anything else.
I think my engine room must be cooler than most or something, only problem I have with my stock alt, is belt dust, and I have a much bigger battery bank.
Yes I know I could benefit with a better Alt and external regulation, but I want to buy Solar first.
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Old 02-03-2015, 07:40   #9
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Re: Most practical way to upgrade Yanmar alternator?

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Originally Posted by a64pilot View Post
My gut feeling is if you just make sure your current Alt has a dedicated supply of cool air,
Given your current Battery bank size, you don't need to do anything else.
I think my engine room must be cooler than most or something, only problem I have with my stock alt, is belt dust, and I have a much bigger battery bank.
Yes I know I could benefit with a better Alt and external regulation, but I want to buy Solar first.
Thanks. I will run the same test I did before but with a fan ducting fresh air in.
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Old 02-03-2015, 08:01   #10
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Re: Most practical way to upgrade Yanmar alternator?

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Originally Posted by hellosailor View Post
"

"The house bank is comprised of one 8D Lifeline AGM rated at about 200Ah. Therefore it can take more than 80A early on but not for very long." Depends on who you talk to. What it "can take" is not what is optimum for it. Most battery makers will tell you that once you exceed 25%C for a charging rate, you will reduce battery life. That would be 50A for your battery.
I do understand the principle but these are Lifeline AGMs that have very low impedance. Lifeline says that "charging current during bulk stage should be set as high as practical.. .. Lifeline batteries can tolerate in-rush current levels as high as 0.5C (500A for a 100Ah battery). "

All that said, I do not really care about getting more than 80A. I would be happy with 80A sustained for long enough for the batteries to reach 14.4V and stay there until the battries are full (ie current drops to say 2A at the battery).

I have tried ventilation with the standard 80A Hitachi and could not find a way to stop the thing from dialling down voltage after a while. I will try again
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Old 02-03-2015, 08:08   #11
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Re: Most practical way to upgrade Yanmar alternator?

I have a fan exhausting air in my engine compt., I ijust have a duct, no fan that flows air onto the ALt. Actually with as much air as the engine removes from the compt from just running, I bet you don't need a fan, just a duct that takes air from the cabin and directs it to the alternator.

If I do the math right a 200 cu in engine at 2,000 RPM will remove 1388 cu ft of air per min.?
Since it's a four stroke it takes two revs for the cylinders to go through an intake stroke, so take 200 cu in x 1000 times per min = 200, 000 cu in, div by 144 to convert to cu ft = 1,388?

I have no idea of your engine size, I used 200 as it's a nice round number, only point is I don't think you need a fan, just a vent hose to direct the air.
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Old 02-03-2015, 08:16   #12
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Re: Most practical way to upgrade Yanmar alternator?

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...........I bet you don't need a fan, just a duct that takes air from the cabin and directs it to the alternator.........
I don't think it's a wise idea to allow air from the cabin and engine room or bilge to mix for several reasons. Ducting air from outside the boat would be fine.
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Old 02-03-2015, 08:30   #13
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Re: Most practical way to upgrade Yanmar alternator?

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Originally Posted by a64pilot View Post
I have a fan exhausting air in my engine compt., I ijust have a duct, no fan that flows air onto the ALt. Actually with as much air as the engine removes from the compt from just running, I bet you don't need a fan, just a duct that takes air from the cabin and directs it to the alternator.

If I do the math right a 200 cu in engine at 2,000 RPM will remove 1388 cu ft of air per min.?
Since it's a four stroke it takes two revs for the cylinders to go through an intake stroke, so take 200 cu in x 1000 times per min = 200, 000 cu in, div by 144 to convert to cu ft = 1,388?

I have no idea of your engine size, I used 200 as it's a nice round number, only point is I don't think you need a fan, just a vent hose to direct the air.
Many thanks; that is great stuff.

The numbers are not as good as that because the 3YM20 only displaces 52 cubic inches and there are 1728 (not 144) cubic inches to a cubic foot, hence you only get 29 cf per minute of air coming in. Still, I have to try this because it is "free".

The question is if this will make the thing cool enough to prevent the 0.01 volt per degree C derating starting at 20 degrees C from taking the 14.3V rated voltage below 14V. I guess in order for voltage to remain at 14V I would need to bring temperature down to 50 degress which may be a bit too ambitious.

Now I will need to change my test setup because for your scheme to work I need to close the engine compartment, hence I will not be able to use the handheld IR thermometer. I will need to stick a K-probe to measure temperature. Thanks again!
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Old 02-03-2015, 09:08   #14
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Re: Most practical way to upgrade Yanmar alternator?

"Since it's a four stroke it takes two revs for the cylinders to go through an intake stroke,"
Nah. It's a FOUR STROKE per cycle engine? Then the four strokes include only one intake stroke. So you'd be sweeping half as much air as you thought. And unless the engine air intake was conveniently at the top and away from the compartment intakes, that would leave mainly hot stagnant air next to the alternator, bathed in radiant heat from the engine, perhaps from the exhaust manifold.
I don't think recreational boat designers have spent much time on the thermodynamics of engine bay airflow yet, beyond "Yeah, it runs." Helps keep the price down.


lamoracha-
No idea what would fit in or bolt up. The last time I needed to replace an alternator was for "more power" but the resource at hand was pretty much "Let's see what they have at the auto store" followed by a look at the online spec sheet, and then a maddening search for a machine shop that would deign to make a simple pulley.


a64-
If you've got belt dust...You know there are different V-belt profiles as well as depths. Sometimes it is just the wrong belt, not just improper alignment. These days, only cheap old sailors with antique boats ever go looking for v-belts, the kids in the auto shops tend to get scared if you come in and ask for them. "Mommy!"
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Old 02-03-2015, 11:20   #15
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Re: Most practical way to upgrade Yanmar alternator?

I have a Yanmar 3YM30 on my Seaward 32RK. The 80 amp Hitachi alternator doesn't put out anything close to 80 amps. The stock fan on the 80 amp Hitachi, doesn't create enough air flow to keep the alternator producing that much amperage. You are going tofind, that when its hot, its going to produce half of that.

I solved this problem for myself in 2 phases.

Phase 1: Installed a Sterling Power Pro Alt C Alternator to Battery Charger (130AMP)

This allowed me to get a better charging profile and still use the internal regulator.

I've got 2 x 100ah Odyssey batteries, so I think the battery capacity is similar to your own.

The Sterling Power unit has worked great and charges batteries within 1-2 hours when running the engine from 50% back to 80% SOC.

I wasn't completely satisfied with the output of the 80 amp Hitachi, so I went to phase 2.

Phase 2: Install serpentine belt kit from Electromaax and 100amp small frame alternator (plus spare).

The small frame alternator has a much bigger fan and open design that allows a lot more airflow. I think I am probably getting 80-100amps now from the alternator when the batteries are deeply discharged. The alternators are still internally regulated, and the Sterling unit has a temperature sensor connected to the alternator that keeps things from overheating. I'm really happy with the combination.

I also have 400 watts of solar, feeding into a Midnite KID marine MPP charge controller.

Chris
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