alternator replacement?

[pjcomeau]

Has anyone replaced the stock alternator for their M-25XP recently? I'm looking for the simplest change. I see from a previous post that there may be a newer Balmar alternator that is the same size. What about regulator?

Is this something I will need a mechanic to do for me?

Thanks,

Pierre

[Stu Jackson]

Simplest change?  That's to buy another 55 A Motorola slap-in replacement alternator, internally regulated, just a replacement for what you already have.  But that's way-old technology.

A very good "primer" on alternator replacement is found in Jim Moe's Projects article: http://www.c34.org/projects/projects-electrical-system-upgrade-2.html

We and others have used the Blue Circle alternator, a very good price unit, successfully.  Balmar and Xantrex make external regulators.

A mechanic shouldn't be needed, an electrician would be the right source.  It is definitely a do-it-yourself job, and you learn a lot from doing it.

Also think about where your alternator output goes.  Get it off the 1-2-B switch and run it to your house bank, then use an echo charger, combiner or switch to charge your start bank.

A recent thread on alternator load management is important to know and understand.  See:  http://c34.org/bbs/index.php?topic=4454.0

[Jon Schneider]

I think Stu's approach and links are simpler, but here's an excellent pictorial of an alternate alternator upgrade approach (www.pbase.com/mainecruising/boat_projects).  BTW, I upgraded to a Balmar 6 series this year (bought the 100a version, but tune it down to 50%) with an external Balmar ARS-5 regulator.  I had bugged Stu for so much advice on other projects over the winter and even on this one, that I figured I'd go with a brand that had excellent telephone support (which Balmar has) in order to give Stu a little bit of break (and I was afraid he was going to start charging me for advice, which would've been worth it at any rate).  I have to say, the world could take a lesson from Balmar's directions.  They provide a huge, easily readable, easy to follow pictorial poster of installation and configuration directions.  The unit fit perfectly.  Works like a charm.  BTW, there was a posting back in July (I think) about a fan belt tensioner that you can get from JC Whitney.  You definitely want that tool.  It's a real bear to get the tension right otherwise.

[Stu Jackson]

Jon, always a pleasure.

So as to help find that article Jon mentioned, go here: http://c34.org/bbs/index.php/topic,3667.0.html

[from a search on tensioner, first hit  - sorry, couldn't resist... ]

The alternator we purchased, the Blue Circle, didn't have ANY instructions.  Heck, the alternator part doesn't need any instructions, since there are only two wires to connect: the alternator output and the plug-and-play plug (literally) from the regulator [yeah, yeah, plus grounds...].  It's the regulator instructions that are important.  And you can get them at Balmar's website and read up on them.  I think have already posted the wiring connections between the two and the wiring harness, also.  If I can't find them and add a link here, I'll post them again.

Here's the old alternator wiring link photo: http://c34.org/bbs/index.php/topic,4432.0.html

Here's a New Alternator Wiring Warnings: http://c34.org/bbs/index.php/topic,3398.0.html

You could consider Rod's Leece-Neville arrangement, but unless you have an alternator shop with a handy dandy friendly knowledgeable proprietor like Rod did, I'd recommend the plug-and-play simplicity of the Balmar or Xantrex external regulators with almost any new high output alternator with the field and stator plugs in the back.  KISS. (KIS, skipper...)

[Stu Jackson]

How to Wire a New Alternator and Regulator

Regulator to Alternator Wiring Sketches - I think I'd posted these before, but it's easier to do it again [l-l-l-last t-t-t-ime f-f-f-olks...Elmer Fudd ]

[pjcomeau]

Jon,

Is this the Balmar alternator you have? Does it fit on the bracket as is?

http://www.jackrabbitmarine.com/balmar-6-series-alternator-system-12v-100a-12-foot-4718

Do you have the temperature sensors to?

Where did you put the regulator?

Do you have your belt tension setting in your ARS-5 regulator to b-7 (you said 50%)? The guide suggested b-5 (??%) for 100a alternator and 3/8" belt, did you know it would be to much load or just being extra safe?

Collecting info for future project.

Thanks,

Pierre

[Jon Schneider]

That's exactly the kit I bought, and, in fact, I bought if from JackRabbit.  They also have very expert technicians on hand to help.  I will say, however, that they charged my card, but apparently didn't have stock, so I believe it took two weeks to get it.  It wasn't a problem for me, but I hate when companies take your money so that they can buy the product they're going to sell you.  Between Stu, Balmar, and JackRabbit, I was able to muddle my way through this relatively painless upgrade.  I did set it to 50% partly to be safe, but mostly to maximize drive HP on my M25-XP.  I'm mostly on shorepower at night, and rarely on the hook for more than one night at a time.  If I need to up the alternator output for a while, it's easy, and I placed the regulator just inside bulkhead (too small to really call it that) running abeam in the aft cabin so that it's readily accessible.  And yes, I installed the temp sensors to the alternator and the starting bank.

[BillG]

I also bought a Balmar from Jack Rabbitt and it is definitely a DIY job for most people.  The OEM equipment had a 2 inch foot and it made sense to buy the same, turns outs that I had to file part of the foot off and then use washers to properly align the pulleys.  You my want to talk to the people at Jack Rabbit about this because the Balmar also comes with a 1 inch foot as well, allows for shimming without having to do any filing.
This is really the time to think about the whole wiring scheme and Stu's advice about direct charging to the batteries and not thru the battery switch is really an excellent idea.