Westerbeke replacement Alternator

[PMF1984]

After 3 years of waiting for my boat to be fixed, the last thing that just arose is a weak alternator. Battery voltage did not get up over 12.2 approx and really fell on its face when bow-thruster was used.

The W100's originally came with either a 51 or 90 amp unit. I don't know what I have as I am not on the boat and it doesn't say on the survey.

After reading more than a few posts, I realize the selection of an alternator is not so simple... but I need to make a selection.

I have no house bank to speak of, but will be putting in a large one in the next year. (used for refrigeration lights and electronics.)

Would like to be able to bring up the house bank after running all day without using the genset.

Advise please. I will either take the old one off for a rebuild or buy a new one on Monday.

 

[High Wire]

I think you wil find an alternator through Westerbeke in the insane region of pricing. The 50 amp for my 8BTD was priced at $950!!!! Try ARCO marine.

 

[Rossland]

Take your old alternator to a place that rebuilds automotive starters and alternators and discuss this with them. Some alternators are easy to upgrade to a larger capacity. 90A is a little on the small side. But if you change alternator brands/sizes you will probably have to also change the mounting brackets. Keep in mind that 100A is about the largest that you can power with a single V belt, so if you go bigger you may have to change pulleys and belts.

 

[psneeld]

Unless you are doing something special with that alternator, any small, one wire alternator that fits would be fine. Heck, any 35 amp alt just to charge the genset start battery is almost overkill.

Some do without genset alternators and just charge the start battery with a charger or just use another battery dource like the main or house bank.

 

[Maerin]

You do mention Westerbeke, but do not mention genset. I presume that this is a propulsion engine, hence the concern about alternator capacity. As ps mentions, for a genset it doesn't make much difference.

I'll 2nd the suggestion to take the alternator to an alternator shop, doesn't necessarily have to be marine, with the caveat that if it's a gasoline engine, the alternator will have to be spark-proof. IIRC a marine gasser alternator has fine metal screens that prevent ignition of vapors, I also presume yours is diesel, so no matter.

Unless the alternator has suffered unlikely catastrophic damage, for any alternator shop in the business, repair should be pot pie, and you won't pay Westerbeke's confiscatory parts prices.Westerbeke doesn't make alternators, they put them in a box with a Westerbeke label and triple the price. If they can't repair it, they can sell you a new one, and address the issue of capacity in the process.

Consider having them convert it to external regulation, that would give you much more flexibility and enable you to use a smart regulator that can monitor case temperature and battery temperature. It's a huge improvement over internal regulation and more insurance against failure.

 

[psneeld]

True about main propulsion...and the W100 might be the hp...sorry for the sidetrack.

 

[PMF1984]

Folks,

Thanks for all the replies. Yes this is the propulsion engine. It is diesel. The Westerbeke 90 AMP alternator is $737: Yikes!

I wonder who made that alternator, as I realize with my experience with both the raw water pump and fresh water pump that the original manufacturer will have it for sale at much less. I can add my own red paint.

I'm trying to avoid the whole changing bracket thing as its coming on three years since I bought the boat (and not been able to use it) and my window for this season is closing - really don't need any more delays.

Is there a place I can read about the external regulation & smart regulation setup?

Also thanks for the tip about double belts for the high amp regulators

John

 

[TDunn]

I got a replacement 50 amp alternator for my Westerbeke from Jamestown Distributors for about 1/3 what Westerbeke wanted for the same alternator. Balmar also makes nice replacement alternators that will fit your engine.

 

[kchace]

John I don't know if you get up this way but there is a GREAT alternator/starter rebuilding place in Tyngsboro MA called Chelmsford Auto Electric. These guys have been in business for a long time. They have done great work for friends and they also did a great job rebuilding my old Alternator and starter for me at very good prices. Even if this place is too far for you there are others and a place like this will KNOW what can be done with your alternator and what other ones will fit.

Ken

 

[Rossland]

Folks,



Is there a place I can read about the external regulation & smart regulation setup?

Balmar Voltage Regulation Technology | Balmar

 

[PMF1984]

Folks thanks for the more specific feedback.

I Checked Jamestown Distributors, they have an "Arco Westerbeke Type Alternator is a 12V, 50A unit with an internal regulator and single groove pulley" for $170.00. (As opposed to the $585 for the Westerbeke model.) But is does not have the same Westerbeke part # reference.

Walmart has "ALTERNATOR REPLACES MARINE WESTERBEKE 24684 INBOARD GENERATOR SETS" for $111 but does not include the pulley wheel and does not seem to include a regulator.

Ken - thanks for the tip. I'm right next to New Bedford Harbor which has one of the best marine support networks on the east coast. I have a good alternator guy - who I've used 3 or 4 times over the year for various machines.

I'm leaning toward a like-kind replacement until I have finalized the other components of my future electrical system.

Apparently the 90A model is a Prestolite 8MR2033TS. There is one on ebay, "110-570 *NEW* OE Leece Neville Alternator 12V 90A PRESTOLITE" for 110.

Will see what tomorrow brings at the boat.

John

 

[FF]

"Would like to be able to bring up the house bank after running all day without using the genset. "

"Arco Westerbeke Type Alternator is a 12V, 50A unit with an internal regulator"

A single wire auto brained alt is not the best for house charging.

When you install the big house batt set you want to be able to bring it back up with out endless running .

Only an alt. with a 3 or 4 stage External regulator can do this well.

About 100A is all a single V belt is reliable for .

The lowest cost reliable setup would be a truck 135A alt (under $140) .

These are built for external regulators , there are a number of marine ones to chose from.

The truck alt will not "drop in" as it is larger and may require a bracket rework.

The larger frame is better at handling the heat from heavy charging .

A drop in same size would be OK , just be sure the little cooling fins are proper for the direction it will be spun.

A second belt would be ideal, if you have room on the engine drive pulley.

 

[bayview]

before replacing alternator check the batteries. From what you describe that is my guess where the problem lies. If they check OK take the alternator to a rebuild shop. Every city has some.

 

[PMF1984]

Bayview - you are so right! When I got to the boatyard this morning, they said every thing was OK as it was just a loose connection.

FF- The engine has the 50A alternator on it. When I size the battery bank, I will then look at the alternator sizing and regulator. Since the alternator is working now, and I have other issues to resolve with the boat, I will wait on this.

I have a 5kw gen-set for bringing up the new bank when I'm on the hook for a few days, also will have a solar panel(s), to delay the need for starting the gen-set.

I thought having a right size alternator plus the solar will satisfy my needs making a seasonal trek on the ICW, should I avoid marinas/docks with electricity.

Good News. I was in the engine room today and noticed a piece of plastic wrap stuck in a cubby hole. I pulled it out (with some resistance) and found a spare starter. I raced home to the rebuild shop and they gave it a clean bill of heath. Is there a good way to store this down below and avoid moisture issues? I will paint it red of course.

 

[Maerin]

I will paint it red of course.

In the FWIW dept, sure, you can buy Westerbeke engine paint for 3 prices, but I discovered that the inexpensive engine paint from the local Autozone or similar source works well, get Chrysler red, Duplicolor DE1632

 

[FF]

"The engine has the 50A alternator on it."

IF the new house batt bank is small enough that 50A will be enough to have a short charge time , simply take the alt to the alt shop and have them remove the garbage internal V regulator , and lead the wire out.

You can then connect a 3-4 stage V regulator as you choose.

Personally I would guess the alt is the size of any old Delco .

Go to NAPA or auto zone with your alt and have them compare it to 1960 ish Caddy or other big car 60-85A units.

These are dirt cheap rebuilt , should fit the existing mounts and are already wired for an external V regulator .

If you cruise enough to make a really big truck alt a good idea , the 3-4 stage V regulator will still work.