Replacement for Hitachi LR135-31 alternator?

ray lunder wrote:

> Ahoy, I could only find one technical reference for this which claims
> it's a 30 amp alternator. Could this be correct?

Yes, that is correct for the alternator for a Yanmar YSM12 which it
sounds like you have.

> I measured about 13.2v output at
> idle and I had to rev the engine to over half throttle to get 14.4v
> out of it. (my batteries were topped up at the time if that makes a
> difference).

Sounds about right.

> It's on a 12hp Yanmar one cylinder diesel and I'd like to charge my
> house batteries (220AH) and a 12v starting battery.

Take a look at Leece-Neville which is now part of Prestolite.

You want a unit that is rated about 60-80 amps, but will have at least
a 50 amp output at engine idle.

Talk to their application people in distributor sales.

I've been away from that business too long to have current knowledge.

Lew





If I'm beginning
> to understand these things I'm to look for an alternator which will
> produce 30% of my amp hour capacity. Since I'll probably charge the
> two systems separately I guess that's around 70 - 80 amps. My crank
> pulley is about 4" diameter, O.D. to O.D.. I need a 3" foot model to
> fit my engine. Any similar experiences, recommendations, empowering
> observations? Ok, the spell chek is complete, I had eleven errors.
> Thanks again.
 >> Stay informed about: Replacement for Hitachi LR135-31 alternator? 

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"ray lunder" <fdfsd RemoveThis @sdfdf.com> wrote
> Ahoy, I could only find one technical reference for this which claims
> it's a 30 amp alternator. Could this be correct?

I think it may be 35A but that is likely the standard alternator Yanmar used
on even the 2-cyl engines.

> It's on a 12hp Yanmar one cylinder diesel and I'd like to charge my
> house batteries (220AH) and a 12v starting battery. If I'm beginning
> to understand these things I'm to look for an alternator which will
> produce 30% of my amp hour capacity. Since I'll probably charge the
> two systems separately I guess that's around 70 - 80 amps.

Yanmar had an optional 55A Hitachi for my engine that with slight
modification of the mounting bolt fits. This is what I have on our 2 cyl
Yanmar and it seems to work fine with our 200AH bank plus starting battery.
We don't have any fancy alternator regulator, but do have a Blue Seas ACR
battery combiner so as to use the maximum output voltage (as opposed to a
diode splitter).

Don't oversize your alternator - That engine may be rated at 12HP, but I
suspect at normal rpm, it would have a hard time making 10HP (BTW- I used to
have that engine on an earlier boat). Check the engine power curve. The
alternator may use up another ~2HP if the batteries are down leaving just
~8HP or less to drive the boat. For our 15 HP 2-cyl Yanmar, Yanmar recommend
no more than 80A but I do know some who have installed 100A units - this can
cause belt problems if the pulleys/belts are not rated for the power
required.

God Luck

GBM
 >> Stay informed about: Replacement for Hitachi LR135-31 alternator? 

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 >> Stay informed about: Replacement for Hitachi LR135-31 alternator? 

Ray,

I did not know that the kit was no longer available. You might try
contacting both Balmar <http://www.balmar.net/> or Amptech (last phone I
have is 817-377-9966 - never found a web presents) and see if either
knows how to do this.

A field shut down switch is machine specific. It can be as easy as
shutting down the lead that goes from the engine instrument power
(ignition, but not on a diesel) or as hard as getting inside the machine
and adding the ability to disrupt the regulator circuit. Manual regular
regulation is not difficult, but on a variable speed driver it is a
receipe for disaster.

The most of the equation is simple 746watts=1hp E*I=W (Volts x Amps =
Watts) The only gray area is the machine's fan loads.

Yes, normal sailboat manuvering time is not enough to keep up the
battery of a cruising boat, but with a little attention and some fast
idle underway or on the hook, it can work.

Stay in touch.
Matt Colie


ray lunder wrote:
> On Fri, 04 Aug 2006 10:33:37 -0400, Matt Colie <mattcolie DeleteThis @netspam.net>
> wrote:
>
>
>>Ray,
>>
>>You got a couple of good answers so far, but I can not resist muddying
>>the water just a little more. The rating published is often optomistic
>>as referenced to sailboat applications as they seldom run at rated speed
>>and are often charging at the top of the recharge curve so they won't be
>>near the published capability.
>
>
> Thanks, everyone. I visited the alternator guy today and got a few
> options.
> It seems the Yanmars are hard to upgrade because of the 3" bracket;
> also, the internal parts are proprietary, no longer available to
> distributors and therefore intentionally expensive.
> If you go to a larger output you really need to go to a larger frame
> as well or heat buildup and mechanical fatigue are issues. A larger
> frame means potential mounting mismatches in my case.
> 100A = 3hp. I don't know where he got this figure but there's a
> formula for converting amperage to hp, I'm sure.
> He had one rebuilt Hitachi 55A model the next size up which is a
> drop-in replacement for $300 and has the correct size pulley.
> (LR155-31). I get to keep my old 35A as a backup. He didn't seem to
> think this would be a big improvement in my case.
> Or there's a new French Motorola 70A that needs a pulley modification
> to make it 2:1 and is a size larger in frame and has an offset ear for
> the adjustment arm so I'm not sure if it will fit or not. It has a
> tach send too. It's $350 and I also keep my old unit. Both are
> internally regulated. Once the batteries are charged it will just stop
> putting out, right?
> Having a one cylinder, low RPM engine also makes the charging curve
> less efficient as Matt suggested so I don't know if just anchoring or
> clearing port will be enough to keep things up. I have one 4.7A solar
> panel but I can't see it being much use on a boat with a mast and
> rigging and all. There's just no where on a small boat to fit it so
> it's unobstructed. Thanks again and smooth sailing.
>
>>There is an available 90amp unit that is a bolt-in kit. It will just
>>take some looking as I do not have the part number available. I know of
>>two of these installations that were done by owners. A Yanmar dealer
>>probably would (expect to be quoted at least 250$us). Some sets I have
>>installed were a 500$ alternator and separate regulator package and the
>>owner has always been delighted.
>>
>>Be aware that 90amp machine will eat near 2hp. That may be critical and
>>if you currently often run at full rack (wide open), you may wish to
>>include a field shut off to get those 2 horses back pulling. It will
>>also destroy drive belts that were less than terrific. Always have at
>>least one spare on hand.
>>
>
>
> Can you describe the field shut off? I read you can fit a high amp
> rated potentiometer, like from a ham radio or tube gear and manually
> control the output that way as long as your willing to monitor the
> system. Can anyone describe this circuit?
>
>>I do several of these upgrades in a typical year. If you have any other
>>questions, I'm here a lot.
>>
>>Fair Wind and Smooth Sea
>>Matt Colie
>>
>>ray lunder wrote:
>>
>>>Ahoy, I could only find one technical reference for this which claims
>>>it's a 30 amp alternator. Could this be correct? That's immeasurable,
>>>that's minuscule- that's nothing. I measured about 13.2v output at
>>>idle and I had to rev the engine to over half throttle to get 14.4v
>>>out of it. (my batteries were topped up at the time if that makes a
>>>difference).
>>>It's on a 12hp Yanmar one cylinder diesel and I'd like to charge my
>>>house batteries (220AH) and a 12v starting battery. If I'm beginning
>>>to understand these things I'm to look for an alternator which will
>>>produce 30% of my amp hour capacity. Since I'll probably charge the
>>>two systems separately I guess that's around 70 - 80 amps. My crank
>>>pulley is about 4" diameter, O.D. to O.D.. I need a 3" foot model to
>>>fit my engine. Any similar experiences, recommendations, empowering
>>>observations? Ok, the spell chek is complete, I had eleven errors.
>>>Thanks again.
>
>
 >> Stay informed about: Replacement for Hitachi LR135-31 alternator? 

"ray lunder" <fdfsd.TakeThisOut@sdfdf.com> wrote
> He had one rebuilt Hitachi 55A model the next size up which is a
> drop-in replacement for $300 and has the correct size pulley.
> (LR155-31). I get to keep my old 35A as a backup. He didn't seem to
> think this would be a big improvement in my case.

ray - This is exactly what we did on our Yanmar 2QM15 - We just use the
internal regulator, and as I mentioned before feed the alternator to the
house bank side of a Blues Seas ACR combiner. When the house batteries are
fully charged, the charge goes to the starting battery.

I was given the 55A alternator but was also sceptical that it would make
much difference. But, I am pleased with the results - I have not measured
the current, but the 200AH house batteries seem to reach full charge quite
quickly.

And, it's easy to swap back to the spare if you have a problem.

With a low horsepower engine, you have to compromise a bit - Maybe larger
solar panel would give you all you need?

GBM
 >> Stay informed about: Replacement for Hitachi LR135-31 alternator? 

1 horsepower [international] = 745.69987 watts (at 100% efficiency. ) (and
one watt is one volt-ampere of course) (For the arithmetically challenged
that's about 62 amps at 12 volts and 53 amps at 14 volts.)

Nigel Calder has written a couple of very good books on the care and feeding
of battery banks. There's a lot more to it than just an on/off switch in
the regulator. You can spend really big bucks for a good smart regulator.

The salesman probably got the 3 hp in the same place they got the 12 hp
output rating, but remember, if it were 100% efficient, it wouldn't get hot.

Roger
derbyrm RemoveThis @NOSPAMinsightbbNOSPAM.com
http://home.insightbb.com/~derbyrm

"ray lunder" <fdfsd RemoveThis @sdfdf.com> wrote in message
news:bbj8d21nl90jsu6vj318lf6uf7gidm7i2v@4ax.com...
> On Fri, 04 Aug 2006 10:33:37 -0400, Matt Colie <mattcolie RemoveThis @netspam.net>
> wrote:
>
<snip>
> 100A = 3hp. I don't know where he got this figure but there's a
> formula for converting amperage to hp, I'm sure.
 >> Stay informed about: Replacement for Hitachi LR135-31 alternator? 

Watts to HP....In 1492 Columbus divided the year in two and converted watts
to horsepower. 1492/2=746watts/hp
"Matt Colie" <mattcolie.DeleteThis@netspam.net> wrote in message
news:yVIAg.13$zK3.9@fe03.lga...
> Ray,
>
> You got a couple of good answers so far, but I can not resist muddying the
> water just a little more. The rating published is often optomistic as
> referenced to sailboat applications as they seldom run at rated speed and
> are often charging at the top of the recharge curve so they won't be near
> the published capability.
>
> There is an available 90amp unit that is a bolt-in kit. It will just take
> some looking as I do not have the part number available. I know of two of
> these installations that were done by owners. A Yanmar dealer probably
> would (expect to be quoted at least 250$us). Some sets I have installed
> were a 500$ alternator and separate regulator package and the owner has
> always been delighted.
>
> Be aware that 90amp machine will eat near 2hp. That may be critical and
> if you currently often run at full rack (wide open), you may wish to
> include a field shut off to get those 2 horses back pulling. It will also
> destroy drive belts that were less than terrific. Always have at least
> one spare on hand.
>
> I do several of these upgrades in a typical year. If you have any other
> questions, I'm here a lot.
>
> Fair Wind and Smooth Sea
> Matt Colie
>
> ray lunder wrote:
>> Ahoy, I could only find one technical reference for this which claims
>> it's a 30 amp alternator. Could this be correct? That's immeasurable,
>> that's minuscule- that's nothing. I measured about 13.2v output at
>> idle and I had to rev the engine to over half throttle to get 14.4v
>> out of it. (my batteries were topped up at the time if that makes a
>> difference).
>> It's on a 12hp Yanmar one cylinder diesel and I'd like to charge my
>> house batteries (220AH) and a 12v starting battery. If I'm beginning
>> to understand these things I'm to look for an alternator which will
>> produce 30% of my amp hour capacity. Since I'll probably charge the
>> two systems separately I guess that's around 70 - 80 amps. My crank
>> pulley is about 4" diameter, O.D. to O.D.. I need a 3" foot model to
>> fit my engine. Any similar experiences, recommendations, empowering
>> observations? Ok, the spell chek is complete, I had eleven errors.
>> Thanks again.
 >> Stay informed about: Replacement for Hitachi LR135-31 alternator? 

"Dave W" <woodwind.DeleteThis@suscom-maine.net> wrote in message
news:0L6dndW2ZO-fqErZnZ2dnUVZ_uydnZ2d@suscom-maine.net...
> Watts to HP....In 1492 Columbus divided the year in two and converted
watts
> to horsepower. 1492/2=746watts/hp

Several smart answers on conversion of units, but none on efficiency of
alternator and that is needed to determine actual HP needed to drive the
alternator.

The figure Balmar quote is 1HP per 25A output at 14V. Others quote even
higher loses.

For original poster, this link should provide much of what you need:

http://www.balmar.net/PDF/Alternator-Regulator%20Guide.pdf

For a 3/8" belt drive, they don't recommend more than 75A. I would not
exceed this unless you want a lot of belt problems and the need for a
complex system to switch out alternator when you need engine power.
Personally, I would stay with the 55A unit.

GBM
 >> Stay informed about: Replacement for Hitachi LR135-31 alternator?