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Westerbeke W 27 Alternator upgrade

19K views 11 replies 5 participants last post by  cwyckham 
#1 ·
Hello all
my first post on this new forum

Has anyone upgraded to a ~ 100 amp alternator ?
How many belts did you drive it with ?
How did you attach it to the engine so the pulleys lined up ?

Any help is appreciated

thanks
George
 
#2 ·
George,
I know I'm replying to an old post, but I bought a boat recently with a Westerbeke 27 and I'm facing the same quesitons you had last fall.
Did you upgrade to a 100 amp alternator, and if so how has it worked?
I have a 375 amp house bank, which would theoretically call for about a 95 amp alternator. I want to upgrade from the present automotive alternator and add external 3-stage regulation.
I know I'd need new pulleys to go to a larger alternator, and I don't know how the main bearings etc will handle the increased side load.
Another option is a 70-amp alternator, keeping the smaller belts and lower strain on the engine, and hopng that the overall charging time won't be too much longer.
What did you end up doing, and how has it worked?
Thanks for any info.
John V.
 
#3 ·
Larger alternator

Hello John

I did upgrade to a 100 or 110 amy Balmar. Westerbeke can supply you with double pulleys for the crank , water pump, and alternator if you get the right one. ( only one )
It works well and with the 2 pulleys you don`t have to tighten it too much , thus minimizing side load.
Depending on where you are located , I might be able to help with some pricing on the pulleys and maybe the alternator too ( not sure ).
I look forward to hearing back

Merry Christmas
George
 
#4 ·
George--
Thanks for getting back to me.
I hadn't realized that double belts would reduce side loading--is it because you need less belt tension?
I emailed a W'beke supplier about pulleys but never heard back.
I'm in upstate New York. Where did you order your pulleys from?
I'm looking at a kit Balmar sells--a small-frame 100amp 6-series alternator plus one of their smart chargers and some ansillary stuff.
The prior owner sprung for a 375A Rolls battery bank but didn't really do much with the charging system other than a 105 amp Delco internally regulated automotive charger, which I don't really trust. So I'm more or less building the system around the batteries.
I'd be curious to know what W'beke gets for the engine and water pump pulleys.
Merry Christmas to you and yours, too.
John
 
#5 ·
alternator

Hello again
You guessed it . There is twice the surface area with 2 belts. It`s all about grip. More grip - less tension.

I am a yacht broker with an aaccount with a Westerbeke distributor &
I can help you with this.

I`ll contact you Monday if you like ( your phone number ? ) and we`ll go from there.

cheers
George
 
#6 ·
Sorry for dredging up a very old thread, but I am trying to do precisely the same thing with a Balmar 7 series 110A.

I'm not sure where to find the right part numbers for pulleys. How big a job is that to replace the pulleys? Is it as easy as it sounds? I could also just derate the alternator somewhat and keep the existing belt, but I'd obviously rather do it right.

Which Balmar fits? None have the 2" saddle of a mitsubishi alternator, so I assume you can use the saddle type 7 series and some shimming is required? Will I also need to replace the adjuster bar, as it looks like the bolt to bolt radius is different on the Balmar?

Any help is much appreciated. I'm going to try to do this in the middle of the cruising season, so I don't want to be down for weeks waiting for parts I didn't know I needed or discovering that it won't fit after all because I got the wrong Balmar.

Chris
 
#7 · (Edited)
The alts on the W27 are a saddle mount Mitsubishi. The Balmar 6 or 7 series as well as the Electromaax saddle mount alts will usually fit though may require a shim or two. It is a tight fit on those motors due to the manifold so the small case alts like the 6 or 7 series or the Electromaax units seem to fit a little better than an older Delco 10DN style etc..

The W-27 engines have a 3/8" belt which means with a perfect alignment you can squeak about 80A or possibly 90A but the higher you go the more belt dust.

Of course the size of your battery bank and its state of charge will determine if the alt can even put out 80 or 90A. A 110A Balmar will often work fine of a well aligned 3/8" belt because when hot it won't be pumping out 110A for very long.

I am not a big fan of "dual belts" systems and find them only marginally better than a single belt. They often stretch at differing rates and it has become quite hard to get a well matched pair these days.

For the price of a custom "dual belt" pulley set up you can have a true 10 cog serpentine belt that will handle as much as 200A on a single belt. Electromaax has serpentine kits but I don't know if they have one for the W27 yet. They do show a kit for the Westerbeke 27 but I am not sure if this is the W-27 or not. Call Rob or Darren at Electomaax and they could help.

The serpentine kits are worth every penny if you are trying to drive high loads. A dual belt system is a band-aid approach, in my's, GEL's or wets in excess of 400Ah.

You can always go with a larger alternator and de-tune a Balmar regulator in belt manager or small engine mode then upgrade the pulleys at a later date. I really prefer the Balmar MC-614 regulator and even when I buy Electromaax, Powermax or Leece-Neville alts I still use Balmar regulators when installing external regulation.
 
#11 ·
I have a 375 AH house bank plus a starter battery, connected via an ACR. A Delco CS130alternator was on the boat, and after researching it's suitability for the purpose, I had a shop convert it to external regulation for around $60. I got a Balmar MC614 regulator and the combination has been fine after 2 seasons. I was concerned about keeping the 3/8" belt and looked into getting doubles or a 1/2 inch. But using the belt load manager on the VR, and just notching it one step down, I've really noticed no appreciable belt wear.
The one problem is that the single foot of the Delco needed machining down to align the pulleys, and they still are not in great alignment.
But as has been pointed out, unless you really run the batteries down, you're not going to be putting a heavy load on the belt for any length of time, and you have the small engine switch if you need it. You can actually observe it if you have a battery monitor--and I think it makes good sense to have one.
Another problem I had with switching to dual belts is that you also have the water pump pulleys to consider. So I don't think I'm going to need to do anything with the belt for now.
John V.
 
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