Hanse 458 Alternator Burnt Out (Yanmar 80hp Sail Drive)

[HurricaneWally]

Hello all!

Last year I purchased a Hanse 458. We have the upgraded Yanmar 80hp (4JH80) engine with 220hrs.

Recently we had a low voltage alarm sound on our engine panel while motoring at approx. 2000rpm. We know now was due to a burnt out alternator.

The alternator unit was removed and sent to Yanmar in Athens for inspection as part of a warranty claim however Yanmar have concluded that the alternator was not at fault and have stated “automatic regulator or diode bridge failure”.

They explained that this may be due to to much current flowing through the diodes (caused by using too many electrical appliances), reversing the battery terminals or potentially shutting down the engine electrical system without shutting down the engine first.

I can say with 100% confidence reasons two and three listed above are not the cause of the alternator failure (because they didn’t happen) and although we do run heaters etc we only do when plugged into shore power or running the genset.

I have had a second alternator installed and have had a full electric diagnostic performed by a local electrician here in Greece to try to diagnose the cause with no luck (he says it’s all reading normal).

This is frustrating because the new alternator is getting very hot and the copper coils appear to be blackening. I am afraid that if I keep using the engine we are going to burn out this second alternator still without having found what the cause of it is. I have only put 1hr on the engine since the new alternator was installed.

I would love some help or advice on trouble shooting to try an diagnose what might be causing my boat to be destroying alternators.

Again we have a 80hp Yanmar engine with standard alternator. We have 4 x 160amp AGM house batteries with a 90amp engine battery and a Victron Battery Monitor.

Any assistance from those more electrically savvy would be very much appreciated!

Many thanks!

James - sv “INTUITION”
Lefkas Marina, Greece

[CharlieJ]

The blackening of the windings is certainly not good. You do not mention it but is the alternator regulated by an external regulator, e.g., Balmar?

Are the alternator and the crankshaft pulley aligned properly and is the belt tension correct?

Here are some initial troubleshooting steps:
1. After depleting the batteries so the alternator has to work hard, use a clamp on ammeter and determine what the current flow is at the B+ output of the alternator.
2. When the alternator is "very hot", use an IR thermo gun to determine the case temperature at its hottest point.
3. Use the IR gun to determine the ambient temperature of the engine compartment when engine and alternator have stabilized at operating temperature.
4. Use the IR gun to determine the temperature of the cooling are leaving the alternator.

Good luck.

[Dsanduril]

According to the specs the stock alternator on the 4JH80 is a 125A unit. For a stock alternator of that size the most output I'd want to see on a regular basis is around 80-90A. Anything greater than that for very long will likely lead to too much heat. Any idea what you are putting out when it gets hot?

[kenbo]

It's not uncommon for AGM batteries to overstress a small case alternator such as the one you have on that Yanmar. What is the SOC of the AGM house bank? If they are down in the 50 to 75% range they could be drawing a lot of current. How many amperes does your Victron battery monitor indicate is flowing during engine running? As a previous poster wrote, more than 80a is cooking that alternator. A possible workaround is to run the engine at a higher rpm than 2000 to get more air flowing through the alternator. But IMO 125a is too much for an internally regulated small case alternator but it looks good in the marketing brochure.

[Ween]

The stock Hitachi and Valeo alternators on Yanmar engines are a joke. I have the "125A" Valeo OEM unit and the coils are burnt black. I too ran 625Ah AGMs off the alternator charge while sailing. These OEM units are dumber than dumb. The internal regulation allows the units to be run way overloaded trying to keep up with your large house bank especially if you asking it to perform bulk.

These are automotive units designed to top off starter batteries. Maybe feed a house battery via parasitic echo charger (e.g. 15A). The 125A rating is initial, cold and high rpm performance output at best.

Option 1 - remote regulation down to 70A max output. This is expensive. Requires both a regulator and $175 conversion kit to make the alternator even remote regulator compatible.

Option 2 - new alternator - I had no room for a large case unit. I'm looking at a balmar xt170 on my office floor right now. I will install it with a regulator and regulate back to a comfortable 100-110A for longevity. This to me is the best one can hope for..100-110 steady state charge from a small-case alternator, and perhaps even that is optimistic.

You won't win the warranty argument. These OEM setups are not built to charge house banks. Through clever language they might seem to imply that they are = marketing.

[kenbo]

An alternative solution that may be the lowest cost would be to charge only the start battery with the engine alternator and use a DC-DC charger from the start battery to the house. Renogy has a 60a DC-DC charger with custom programming. This should keep the alternator in its happy zone.

[more]

Originally Posted by HurricaneWally

Hello all!

The alternator unit was removed and sent to Yanmar in Athens for inspection as part of a warranty claim however Yanmar have concluded that the alternator was not at fault and have stated “automatic regulator or diode bridge failure”.

They explained that this may be due to to much current flowing through the diodes (caused by using too many electrical appliances), reversing the battery terminals or potentially shutting down the engine electrical system without shutting down the engine first.

Under EU law, within the legal guarantee period of two years, defective products must be repaired or replaced without any cost to the consumer.
Next time don't talk with yanmar or any service .call your boat dealer and demand repair or you go to court with lawyer . You win law is on your side this alternator must work how is declared in CE certificate for example 125A 200 hours without stop . Or Yanmar must pull from market all this alternator and exchange this with valid alternator

[sailingabe41ds]

Hi..
It sounds like your alternator is working xtra hard for the size bank you have. Almost had to replace my alternator which is probably the same as yours. The prices are all the same and you are only allowed to buy from your local Yanmar dealer ( how that is legal with all these anti trust laws is beyond me).
When this is resolved, I suggest you bite the bullet and get a Balmar with external regulator and keep the OM as a back up. I was going to order a back up alternator. However, at $320 plus the local Yanmar dealer wanted to charge me anywhere from $30-100 shipping charges that the distributer in Georgia was going to charge him I decided to cancel my order. This just happened...so I am still little pissed. BTW, I have not been able to find a direct aftermarket for this alternator. If someone knows a good aftermarket let me know. It is a part number Valeo SG10S078 or Yanmar 128990-77250.

Best
Abe

[sailingabe41ds]

Hi.

Its me again. I called Balmar and they told me that the Valeo alternator itself is not a bad alternator but the internal regulator is where it is lacking.....could be all marketing. After more research the Valeo alternator is a bargain at $320 when a Balmar is $1000. There is a retrofit conversion kit at Balmar that you can use the Balmar external regulator with existing Valeo alternator bypassing the Valeo internal regulator. It comes with both alternator and battery temperature sensors so if it gets too hot the regulator will control the alternator output. It costs about $600 (also not cheap) but it may save your alternator in the future when your warranty expires. With the kit you are able to use existing Valeo or you can purchase one of their 170 amp alternator which may solve your problem if money is no object.
I would also consider making holes in the plastic safety shield in front of the engine for better cooling....my 3JH5E comes with one and assume your Yanmar does too.
This is all assuming that the issue is overworked alternator for too big of a battery bank.

Good Luck..

Abe

[kenbo]

This Delco Remy is a replacement for the Valeo. However, it is rated at 100a rather than 120-125a which to my mind is not a bad thing for a small case alternator. And the price is good as well.
https://spareto.com/products/delco-r...rnator/dra3944

[kenbo]

The Balmar 170a alternators are based on the Denso hairpin wound stator alternator. Those windings are more efficient, read produce less heat, but that 170a rating is not a continuous rating. So if you buy that alternator you also must buy the external regulator and the serpentine belt kit and the alternator temp sensor. After all that you still need to derate the alternator's output to about 120a to keep it cool enough to run on a continuous basis. That's a lot of money to charge lead-acid batteries with their diminishing acceptance rate above 80-85% SOC. IMO there's very little value in that proposition.

[more]

he have a better in-home alternator
Type AAN compact iskra
or Iskra 350A water cooled 20 kg without regulator
Alternators
Also in Slovenia, Croatia every bigger city have 5-10 workshop for repair alternator and DC motor.
For example, I simply take off the alternator if have similar put in the boat and broken give a workshop and for 1-3 days alternator is repaired.

[skipperpete]

Originally Posted by kenbo

An alternative solution that may be the lowest cost would be to charge only the start battery with the engine alternator and use a DC-DC charger from the start battery to the house. Renogy has a 60a DC-DC charger with custom programming. This should keep the alternator in its happy zone.

That’s a good idea with the Dc-Dc charger but not inexpensive, my DC-DC was $AU750 and it has settings for all the usual battery types. After many years of failed house banks I took advice from the caravan and 4WD crowd and got a Redarc DC-DC charger that does the job as advertised and I’m surprised that the yachting community hasn’t embraced this simple device considering the complex charging profiles in our Ac-DC chargers.... or has it and I missed the threads?
Pete.

[kenbo]

Originally Posted by skipperpete

That’s a good idea with the Dc-Dc charger but not inexpensive, my DC-DC was $AU750 and it has settings for all the usual battery types. After many years of failed house banks I took advice from the caravan and 4WD crowd and got a Redarc DC-DC charger that does the job as advertised and I’m surprised that the yachting community hasn’t embraced this simple device considering the complex charging profiles in our Ac-DC chargers.... or has it and I missed the threads?
Pete.

The Renogy 60a dc-dc charger is $260US https://www.renogy.com/12v-60a-dc-to...ttery-charger/