Alternator

[saltygirl]

Does anyone have a good recommendation for replacing the alternator? Thank you.

[mainesail]

Does anyone have a good recommendation for replacing the alternator? Thank you.

Budget?
Desired amperage?
Internal or external voltage regulation?
What engine?
How big is the battery bank?
How is it currently wired?

If looking for externally regulated there are now a number of different options for the Universal engines..


MarineHowTo.com - Alternators

[saltygirl]

Budget: under 500$
Engine: universal 35b
Amperage: book says 52
Battery bank: 2 batteries

Sorry for not posting enough information 😁

Greg and Celeste Ray
Solitude

[scgunner]

    Greg and Celeste,

       Why do you want to replace your alternator? Has it failed or are you looking to improve your charging ability. I know you're not going to want to hear this but if it's the latter then the best way to approach this is usually a system upgrade. We're talking about a more robust alternator, a smart regulator, upgraded wiring, more storage capacity(batteries), and a few other bits.
        The stock charging system on the Cat 34 is very much like an automotive charging system. What this system does is spike the charge after the start for a few minutes to replace the power used for the start. After that it drops off to a low maintaining float, auto systems are designed mainly to start the motor not charge batteries. If your boat is like mine was I could run my motor for hours and barely manage a start a day or two later if I used the fridge or any significant use of lights.
         I found a marine electrician who specialized in marine charging system upgrades and now I can run the motor for two hours every other day while on a mooring and keep the batteries charged, run my accessories, and get a motor start when needed.
         Sorry to ramble guys I'm sure you were just looking for a brand and model number.

[KWKloeber]

Budget: under 500$
Engine: universal 35b
Amperage: book says 52
Battery bank: 2 batteries

Sorry for not posting enough information 😁

Greg and Celeste Ray
Solitude

Need more info.
Why are you replacing it? Because you WANT to (better charging?) or because you NEED to (why, what happened?)
If all you are looking to do is replace what you have, then I'd suggest:
Simply do a rebuild on yours.  Easy peazy for a decent auto electric shop near you.
A Wilson remanufactured.  I have sold several of these (different models,) and they are excellent quality, 1 yr warranty.  I understand that Wilson is the largest auto electric remanufacturer in N America.  What is the model number? Not regulator number (on the back) but the number stamped into the side case, aft of the pulley.  You likely have the internall-regulated and internal-sensed 8MR2049? or similar Motorola alternator.  They should have the identical frame in their reman stock or they have a 72 amp substitute that works with a slightly different case, same 2" mount, and has the external sense (still internal, no adjustable regulated, though.)  But if your supplier will work with you they can get Wilson to go thru thru their reman database and ship the one with the regulator that has the highest voltage set point (they test the reman units.)  (Or put on an external regulator.)

More specifics would help us help you.

Ken

[saltygirl]

Ours had been rebuilt twice and failed.  Not necessarily looking to upgrade, just replace it.   

Greg and Celeste Ray
solitude

[mainesail]

Ours had been rebuilt twice and failed.  Not necessarily looking to upgrade, just replace it.   

Greg and Celeste Ray
solitude

It is likely trying to tell you something. It is likely telling you that it's undersized for the work you are asking of it. These are basically automotive alternators that were really never intended to charge the deeply cycled banks of batteries we are seeing today on many 30+ footers. 

As Ken say if you want the same alt you'd need the model # off it. There are many replacements for that alt in the 72A to 105A range.

[britinusa]

I can attest to the quality of the Alternators that Mainsail offers.

http://www.pbase.com/mainecruising/buy_cmi_alternator

Paul

[mark_53]

Ours had been rebuilt twice and failed.  Not necessarily looking to upgrade, just replace it.   

Greg and Celeste Ray
solitude

I tried to find model number on mine with no luck.  I can tell you it's a 52amp Motorola but not much more.  Best bet is to take it to your local autoparts dealer and compare side by side with a new or rebuilt one.  It depends on how you use your boat if a larger alt is necessary. If you are a day sailor with a few overnighters or marina hopper, the 52amp should be fine.

[mainesail]

The problem with older Motorola's is that they offered a 17mm shaft (pretty much industry standard) and a 5/8" shaft (not at all industry standard). Pulley's for the 5/8" shaft are difficult to find.. Universal/Westerbeke used both 17mm shaft alts and 5/8" shaft alts.. These units do not ship with a pulley, just a fan, so trying to buy a replacement alt becomes difficult unless you know what you actually have. The part number on older Motorola alts is stamped into the foot. Can you get us a photo of the alternator?

Universal sells a 72A replacement alternator for about $600.00. I can generally sell the same identical alt, including the 1" to 2" foot spacer kit, with a billet machined pulley, not a cheap stamped pulley, for about $250.00 +/- depending upon model. Once you know the shaft size you just pick the amperage you want.                                                         

[KWKloeber]

Ours had been rebuilt twice and failed.  Not necessarily looking to upgrade, just replace it.   

Greg and Celeste Ray
solitude

I tried to find model number on mine with no luck.

Mark

See pic below - zoom in next to the foot to see a typical m/n "8MR.... in this instance.)

ken