Alternator Replacement

[Bryce Custer]

The Hitachi 80 amp alternator (LR180-03C, 119573-77201, 12V-80A) on my Yanmar 4jh3 died.
Looking online at replacements I see pricing anywhere between $82.00 up to $1,100. Since I have a generator, not really interested in Balmar upgrade, would prefer to stick with plug and play unit.
Other than "You get what you pay for", what are the differences?
Any recommendations?
Bryce

 

[Bill Roosa]

Unless you plan on splashing it with sea water (raw water hose breakage???) Hatachi 80 amp is hatachi 80 amp. The $1.1k is probably due to it being sold in a marine shop. Try the auto parts store also.

 

[Stu Jackson]

Second time I've posted this this week: just be aware of the features of these alternators, no reason why you can't buy a "regular" one.

Thanks to MS

The problem with all Yanmar/Hitachi alternators, except some very old models, is that they can lead to chronic under charging and extremely slow bulk & absorption charging. Why? These alternators have a built in thermal protection system that works by lowing the target voltage point as the alt heats up.

Most of the Yanmar/Hitachi alts begin temp compensation at 20C / 68F and drop the voltage by 0.01V for every degree above 68F. When you consider that most of these alts will run at 210-220F+ in bulk that means:

220F - 68F = 152 degree difference

152 X -.01 = -1.52V drop in the alternators max voltage output at 220F.

The specs will also say things like 14.4V (+/-0.3V) for the regulated voltage. Let's assume your reg was producing the spec of 14.4V and your alt is now running at 200F.

That is a 132 degree rise above 68F so 132 X -.01V = -1.32V

14.4V - 1.32V = 13.08V at the batteries :cussing::cussing:

This is NOT INCLUDING ANY VOLTAGE DROP IN THE WIRING

Lowering the voltage point reduces accepted current by the battery bank and allows the alt to cool... It is a safety feature for the alternator but a death feature to your batteries...

Any upgrade beyond a factory Yanmar/Hitachi alt is a good one.... ShareThis
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-Maine Sail / CS-36T

search tag: Hitachi reasons

 

[Bill Roosa]

They will keep your start battery topped of nicely though and since you have a genset to charge the house batteries.........

 

[Ken13559]

I recently replaced a faulty Hitachi alt with this http://www.ebay.com/itm/New-Alterna...ies&hash=item3f19d606b4&vxp=mtr#ht_2749wt_748
Works great for no frill alternator.

 

[artboas]

On my 40.5

I recently replaced a faulty Hitachi alt with this http://www.ebay.com/itm/New-Alterna...ies&hash=item3f19d606b4&vxp=mtr#ht_2749wt_748
Works great for no frill alternator.

I had the original Hitachi 80 amp unit.
I upgraded to a high output balmar which worked well.
I kept the hitachi as a spare.
After I sold the boat I still had it. In new condition, I put it on eBay for a $100 buy it now. Somebody snapped it up within an hour. Now I know why!!