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Old 04-08-2014, 11:07   #1
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Alternator - Hitachi to Prestolite Swap out ??

After some advice - Swapping out the Yanmar OEM Hitachi Alternator for a 'hot rated' 90 amp Prestolite - hopefully more resilient. Keep Hitachi as spare.
The supplier is still thinking it thru !

ref : Engine Yanmar 4JH4-TE with OEM alternator Hitachi 119573-77201 80 amp.
(Not interested in any regulator type advice or comments thnx

Help requested / Question - the Hitachi has a T plug (tagged R & L). I understand R to be for Alternator excite and L for Control Panel warning light (goes off when alternator outputting) The Prestolite has only an IND connection. See diagrams of both.

So my question / query is - what do i do with the R & L connections - which goes to what on the Prestolite Alternator ?? - Thanks in advance.


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Old 05-08-2014, 04:34   #2
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Re: Alternator - Hitachi to Prestolite Swap out ??

oooo - all so quiet. No armchair speculators

Well ... the answer from the Supplier (Adverc - whom were v.helpful so far) was that I disregard the 'R' connection and just use the 'L' connection - which will serve as both excite circuit and lamp indication.

We will see how it goes.....

BTW .. reason i am doing this, is that I have swapped out my external alt regulator for a Sterling A2B charger and i am now (for the first time) seeing significantly more amps coming from the alternator and hearing the alternator working much harder than before - so something has changed. The Hitachi alternator is temp monitored but as well as adding additional cooling , I am adding a more robust alternator (at a reasonable price point). We will see how that goes also ...

Next question is the belt - currently single 1/2" - should be ok below 100amps ?
BTW - in my Googling - it looks like Yanmar 4JH4 comes with a 125 amp alternator and Serpentine belt now ? - or maybe this is just this supplier ...
http://mastry.com/mec/new_products/i...fs/4JH4-TE.pdf

Tally-Ho ...
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Old 05-08-2014, 05:58   #3
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Re: Alternator - Hitachi to Prestolite Swap out ??

Check, I am pretty sure that the Hitachi has an entirely different mount than the Presolite.

David
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Old 05-08-2014, 06:30   #4
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Re: Alternator - Hitachi to Prestolite Swap out ??

Regarding belt size, my guess is you're fine with a good quality 1/2" belt.
100 A X 15 vdc = 1500 watts / 746 watts per hp = 2.01 hp. I used 15 v to give a little wiggle room.

Could be several reasons Yanmar is going with serpentine; cost, inertia, fashion, utility, you pick one. The ultimate reasons for your belt choice would seem to be mechanical compatability with the horsepower required and with your existing pulleys.

You can figure out the actual recommended ratings for any belt configuration by googling something like "V belt hp ratings" and using any of the calculators that pop up to confirm the belt will work.

Best of luck with it.
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Old 05-08-2014, 07:34   #5
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Re: Alternator - Hitachi to Prestolite Swap out ??

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Originally Posted by djmarchand View Post
Check, I am pretty sure that the Hitachi has an entirely different mount than the Presolite.

David
Hope not ... Yanmar mount - 3.15 = 80mm Prestolite 82mm = 3.2" and the shim moves in... Have i missed something ??

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Old 05-08-2014, 07:45   #6
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Re: Alternator - Hitachi to Prestolite Swap out ??

No you haven't missed anything. I thought that Prestolites used a single foot mount like Delcos. Obviously not for that one.

Balmar, as one reference, does not recommend more than 100 amps on a single belt. So you should be ok there.

Good luck with your project.

David
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Old 05-08-2014, 09:05   #7
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Re: Alternator - Hitachi to Prestolite Swap out ??

Thanks guys - for the feedback.

few more photo's if anyone is interested.

Out with the Old - Sterling external reg and Shoreline split charge.
Only saw max 20 amps from this, big volt drop and forever to charge my service bank.


In with the new ... Sterling A2B160



Sterling 0 volt drop split charge and larger cables



Only a shore-side quick test .. battery's at 70% - never seen this before !! 67 amps .. I think something maybe amiss - maybe solar kicking in as well. Need to do more testing. But big amps :-)




Will let you know how it plays out .. new alternator in next week

Tally-Ho
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Old 05-08-2014, 13:17   #8
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Re: Alternator - Hitachi to Prestolite Swap out ??

Jim,

Your equation forgets a 100 amp hot rated alternator is only 50% efficient.

So 746 watts / 50% eff = 1492 watts = twice the HP to drive the alt at full.

100 A X 15 vdc = 1500 watts / 50% = 3000 watts. 3000 / 746 = 4.02 HP required by the prime mover.

Lloyd

Quote:
Originally Posted by jimbunyard View Post
Regarding belt size, my guess is you're fine with a good quality 1/2" belt.
100 A X 15 vdc = 1500 watts / 746 watts per hp = 2.01 hp. I used 15 v to give a little wiggle room.

Could be several reasons Yanmar is going with serpentine; cost, inertia, fashion, utility, you pick one. The ultimate reasons for your belt choice would seem to be mechanical compatability with the horsepower required and with your existing pulleys.

You can figure out the actual recommended ratings for any belt configuration by googling something like "V belt hp ratings" and using any of the calculators that pop up to confirm the belt will work.

Best of luck with it.
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Old 05-08-2014, 14:30   #9
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Re: Alternator - Hitachi to Prestolite Swap out ??

LLoyd,

Didn't think about that, thanks.

This is one of the good things about this forum, the confirmation of the fabled "wisdom of the crowd". (hope you don't mind being lumped into the crowd)

Think d4 will still be OK (I've got a 3hp 3600rpm table saw that runs a 1/2" belt on
2 1/4" pulleys on both sides with no slipping ripping 3" teak), but would still run the numbers through a calculator to be sure.

Regards
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Old 12-11-2014, 08:57   #10
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Re: Alternator - Hitachi to Prestolite Swap out ??

Hi folks,
I have a 90A Prestolite on my Yanmar 3YM30 in place of the std 80A Hitachi. No problems with the standard belt as yet, and lots more amps for much longer than the Hitachi. I have also fitted the Adverc controller ( also had one on our last boat ) - it's a great piece of kit with excellent support. I have just got to figure out a way of getting some cool air to the alternator now - the engine box on our Southerly is pretty confined!
Regards
Rob Southerly 110-060 'Norman James' currently West coast of Scotland.


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Rob Heath, Southerly 110-60 'Norman James'
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