Replacement API 20025 alternator

[Brinky63]

I have a API 20025 alternator installed on my yanmar 2gm20f which has three batteries, one starter for the engine, one operations and one starter for windlass and head.

I keep my batteries charged using a battery charger while at the dock so the alternator is only used to maintain the batteries while i'm out on the water enjoying the boat. No solar panels or wind generators.

What are my alternatives to changing this model or do I just get the same one? I am leaning towards a simple Napa alternator which half the amps but can do the trick. Just noticed that the connectors are a bit different.

Any thoughts are welcome.

 

[Pearson 39-II]

Pardon, but why replace your alternator at all? What is the problem and what do you hope to achieve in the replacement decision?

 

[DayDreamer41]

If it ain't broke don't fixit, if it is broke fix it right. Automotive style alternators are not suitable for marine applications, you may want to do a bit of research on the musing of mainesail a resident expert on boat charging system here at SBO.

 

[Brinky63]

the unit is overcharging the batteries, it's output can run to 16 volts with two batteries connected.

 

[SycloneDriver]

Take it to an alternator shop and have it repaired.
It probably just needs a new voltage regulator, you could do that yourself.
Many auto parts shops will test alternators for free.

 

[DayDreamer41]

You could xonvert it to an external regulator

 

[Pearson 39-II]

• Your API 20025 has an internal regulator: http://www.apimarine.com/marine-electrical/yanmar-perkins-94-amp-alternator-129772-77200.html
• It should never put out a voltage higher than about 14.5VDC, so its regulator is toast.
• A brand new one will run you about $238 and would continue to supply 94 amps.

 

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[Brinky63]

got a new regulator put in and a quick service and cleanup and she is working like a charm. Question i have is which cable goes to the panels "charge" light which should light up if the alternator stops charging?

 

[DayDreamer41]

On my 4JH4E its the Blue with Black tracer

 

[Pearson 39-II]

got a new regulator put in and a quick service and cleanup and she is working like a charm. Question i have is which cable goes to the panels "charge" light which should light up if the alternator stops charging?

On the 3HM35, the 3GM30, 2GM20, and 1GM10 Yanmar diesels the charge light also connects by way of the blue with black tracer harness wire to the "L" terminal of the alternator.
See pages 127 and 128 in the manual:
https://j109.org/docs/Yanmar_3GM30F3.pdf

 

[Brinky63]

thanks. will take a look