Larger Alternator for Yanmar 4JH5E

auditdata

auditdata

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www.sephina.org
Hi
I am just buying a new Yanmar Marine engine the 4JH5E
The alternator OEM is 80amps but I need at least 120A or more
I have so far emailed electromaax and energy-solutions but neither have replied. Yanmar also seem to be quiet on the subject
Does anyone know of a direct replacement for the original and if so which one and where from.
Thanks
Clive
www.sephina.org
 
The 4JH5E runs the standard alternator on a single V-belt, so about 90-100A is the biggest alternator you could sensibly drive. Yanmar offer an optional second alternator, and this could be your best bet if you need extra power, and it would have the added benefit of redundancy if one alternator were to fail.
 
auditdata said:
Hi
I am just buying a new Yanmar Marine engine the 4JH5E
The alternator OEM is 80amps but I need at least 120A or more
I have so far emailed electromaax and energy-solutions but neither have replied. Yanmar also seem to be quiet on the subject
Does anyone know of a direct replacement for the original and if so which one and where from.
Thanks
Clive

Perhaps look at the range of Balmar High output alternators and their "AltMount" serpentine pulley kits
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pvb said:
Possible, but very pricey! Probably be cheaper to go the Yanmar option route.
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I never managed to get a quote on that Yanmar option for my older 4JH4AE with standard 80A alternator. I did buy a 110A spare that should still run on the standard V belt but haven't fitted it yet. I thought that was about as high as I'd get without going to a serpentine pulley and that seemed to be expensive.

I assume that you have AGM batteries and that's why you need at least a 120A alternator.
 
pvb said:
The 4JH5E runs the standard alternator on a single V-belt, so about 90-100A is the biggest alternator you could sensibly drive. Yanmar offer an optional second alternator, and this could be your best bet if you need extra power, and it would have the added benefit of redundancy if one alternator were to fail.
Click to expand...

Yep unfortunately with the second alternator from Yanmar it does not fit in the engine bay.
 
Because I will have 520AH domestic AGM batteries and will soon be living aboard. We will be power hungry!
Lots of tech. I have a generator, solar and towed generator and when using the engine I want to get as much in as possible!
 
VicS said:
auditdata said:
Hi
I am just buying a new Yanmar Marine engine the 4JH5E
The alternator OEM is 80amps but I need at least 120A or more
I have so far emailed electromaax and energy-solutions but neither have replied. Yanmar also seem to be quiet on the subject
Does anyone know of a direct replacement for the original and if so which one and where from.
Thanks
Clive

Perhaps look at the range of Balmar High output alternators and their "AltMount" serpentine pulley kits
Click to expand...
Thanks that looks just the thing. Same they didn't reply to my email. I will have to telephone them on Monday
Click to expand...
 
auditdata said:
Because I will have 520AH domestic AGM batteries and will soon be living aboard. We will be power hungry!
Lots of tech. I have a generator, solar and towed generator and when using the engine I want to get as much in as possible!
Click to expand...

Get in touch with Adverc, they'll provide the smart controller and an appropriate alternator.

I've fitted a variety of alternators to the two Yanmars I've had - on the 2GM, after the original Hitachi 35 amp burnt out, a Lucas marine alternator of 90 amp output and finally a 110 amp output Magnetti Marelli. The Magnetti Marelli fitted to the replacement 3YM was, replaced by an Iskia 120 amp unit, a brief sojourn with the standard 60 amp Hitachi (which melted) and now a 90 amp unit of unknown provenance.
I've never had to fit any special belts or extra pulleys - just use a heavy duty, serrated one.

The period over which I'm talking is 22 years - the most reliable was the Magnetti Marelli and quite easily the least successful have been the two Hitachis.
 
auditdata said:
Because I will have 520AH domestic AGM batteries and will soon be living aboard. We will be power hungry!
Lots of tech. I have a generator, solar and towed generator and when using the engine I want to get as much in as possible!
Click to expand...

OK, I guess AGMs will accept charge more readily. I have a 90A Prestolite Leece-Neville alternator charging 630Ah of maintenance-free batteries. I used to have a 140A alternator, but it was a large-case model and vibrated the mountings to pieces, not to mention shredding belts!
.
 
pvb said:
OK, I guess AGMs will accept charge more readily. I have a 90A Prestolite Leece-Neville alternator charging 630Ah of maintenance-free batteries. I used to have a 140A alternator, but it was a large-case model and vibrated the mountings to pieces, not to mention shredding belts!
.
Click to expand...
Yep I want to avoid the worn belts and vibrating to bits. I have looked at the Yanmar Serpentine kits here and they seem to offer the solution. Will phone them on Monday and post my findings.
 
auditdata said:
Yep unfortunately with the second alternator from Yanmar it does not fit in the engine bay.
Click to expand...

I've just had a thought about possible warranty issues as your engine is new. I remember reading a technical note for the 4JH4AE somewhere regarding fitting of larger alternators. It was a few years ago but I think that Yanmar didn't approve of replacing the standard Hitachi alternator with units larger than 110A (or thereabouts).

I think the problem was due to excessive loads on bearings (crankshaft & water pump) when larger alternators were fitted. I remember reading that they were worried about bearing life. I believe that their twin alternator setup is meant to be fine because it balances the load as alternators are on opposite sides of the engine. I didn't get a quote for twin alternator mount and never chased it up as it looked like a tight fit anyway.

I'm afraid that this is based on pretty vague from a few years ago. However, it might be worth asking Yanmar about possible warranty impact of fitting a larger alternator. Worth asking Yanmar now before you buy a new alternator and keep their written reply if they say it won't be a problem.

I finally decided that 110A was a good compromise for me. I couldn't believe that serpentine mod. (just 3 new pulleys) would cost £500 and twin alternator kit might be twice that, plus an alternator.
 
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PCUK said:
Fit an Adverc and leave the alternator alone.
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A bit confused. The alternator is 80A and are you suggesting leaving it alone and doing something else? I read the earlier post but not sure what "Fit an Adverc" means. I've looked up the website but I'm not much clearer. Are you thinking that their solution would not have potential warranty issues? Sorry if I am being thick.
 
An Adverc add-on regulator will boost the alternator voltage to achieve greater charging efficiency. However, AGM batteries do tend to be able to happily absorb high charging currents, so you might not gain much. Fitting the Adverc involves modifying the alternator, which technically could void its warranty. A non-invasive solution is the Sterling Alternator-to-Battery Charger, which achieves similar results, but again, with AGMs you might not see much benefit.

One thing to investigate is the output curve of the alternator, and whether it achieves sensibly high output at reasonable revs. Better alternators tend to have good low-speed output.
.
 
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auditdata said:
A bit confused. The alternator is 80A and are you suggesting leaving it alone and doing something else? I read the earlier post but not sure what "Fit an Adverc" means. I've looked up the website but I'm not much clearer. Are you thinking that their solution would not have potential warranty issues? Sorry if I am being thick.
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I'm guessing that he is referring to the fact that alternators often only get close to rated output for a short time. e.g. 80A alternator might run at 70A for 30 mins. and drop rapidly to 20A because th regulator is a bit dumb.

So fitting a smarter regulator might actually give you much more Ah per £ spent on kit. Good point I suppose but there's a downside in that you will work the alternator much harder and it might fail (assuming it was only designed to give 80A for a short while). You also have AGM batteries and they will tend to soak up a much higher charge than flooded batteries so might not gain that much.
 
pvb said:
An Adverc add-on regulator will boost the alternator voltage to achieve greater charging efficiency. However, AGM batteries do tend to be able to happily absorb high charging currents, so you might not gain much. Fitting the Adverc involves modifying the alternator, which technically could void its warranty. A non-invasive solution is the Sterling Alternator-to-Battery Charger, which achieves similar results, but again, with AGMs you might not see much benefit.

One thing to investigate is the output curve of the alternator, and whether it achieves sensibly high output at reasonable revs. Better alternators tend to have good low-speed output.
.
Click to expand...

Just beaten to it. Good point about output curve, that's why I stuck with a 110A replacement. It had much better output at lower rpm and actually gave a much larger boost than you'd think when going from 80A to 110A (at normal cruising speed). Still theoretical of course as I haven't fitted it yet. One other problem with changing the alternator is that you will probably affect the tachometer. I think that you'll find that the alternator sends a pulse to the tachometer each revolution. Unfortunately, the engine turns at a different speed and the rev. counter is setup to allow for this. Not a big problem for me as I downloaded setup instructions and did some calcs. to get the corect adjustment factor.

You need engine pulley size, alternator pulley size and some technical info about the alternator. Of course you could be lucky and find that nothing has changed.
 
auditdata said:
A bit confused. The alternator is 80A and are you suggesting leaving it alone and doing something else? I read the earlier post but not sure what "Fit an Adverc" means. I've looked up the website but I'm not much clearer. Are you thinking that their solution would not have potential warranty issues? Sorry if I am being thick.
Click to expand...

The Adverc referred to is an external alternator controller - another one is made by Sterling Products. They will either of them result in getting far more charge into your battery bank but are unlikely to do it very much faster than with a modern alternator. I would suggest that your best bet would be to consider fitting an external controller as part of the upgrade but doubt if the 80 amp alternator will be adequate for the size of your battery bank. It takes about 120' to fully recharge my 330 ah from 12.0v with a 90 amp alternator and with previous even larger alternators the time taken was about the same.
As to warranty issues, you'd almost certainly leave a loophole for Barrus to wriggle out through, by changing the alternator, however Yanmars seldom have problems which are not down to inept installation.
 
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