Will any alternator do? - SailNet Community

   Search Sailnet:

 forums  store  


Quick Menu
Forums           
Articles          
Galleries        
Boat Reviews  
Classifieds     
Search SailNet 
Boat Search (new)

Shop the
SailNet Store
Anchor Locker
Boatbuilding & Repair
Charts
Clothing
Electrical
Electronics
Engine
Hatches and Portlights
Interior And Galley
Maintenance
Marine Electronics
Navigation
Other Items
Plumbing and Pumps
Rigging
Safety
Sailing Hardware
Trailer & Watersports
Clearance Items

Advertise Here






Go Back   SailNet Community > On Board > Gear & Maintenance
 Not a Member? 
  #1  
Old 10-30-2007
Senior Member
 
Join Date: Sep 2007
Posts: 171
Thanks: 0
Thanked 0 Times in 0 Posts
Rep Power: 8
hertfordnc is on a distinguished road
Will any alternator do?

I just blew the alternator on my Yanmar 2QM20. Given that I am going to rework the electrical system how much difference does it make to have that specific alternator? I'm fairly new to this. The mount itself is adjustable and all the marine alts I've seen seem to have the same general mount.

Am i missing anything?
Reply With Quote Quick reply to this message Share with Facebook
  #2  
Old 10-30-2007
Senior Member
 
Join Date: Jun 2006
Posts: 2,394
Thanks: 0
Thanked 1 Time in 1 Post
Rep Power: 11
cardiacpaul is a jewel in the rough cardiacpaul is a jewel in the rough cardiacpaul is a jewel in the rough
what... did you blow? diode plate, rectifiers, regulator, and how do you know its blown? was it a victim of "smoke technology?" (works till the smoke comes out)
__________________
We are not primarily on earth to see through one another, but to see one another through

Some people are like slinkies: not really good for anything... but you can't help laughing when you push them down the stairs
Reply With Quote Quick reply to this message Share with Facebook
  #3  
Old 10-30-2007
Bermuda's Avatar
Member
 
Join Date: Jan 2001
Location: Northern New Jersey
Posts: 92
Thanks: 0
Thanked 0 Times in 0 Posts
Rep Power: 14
Bermuda is on a distinguished road
You do not need to go with original equipment. The key is the yoke size and pulley alignment. That particular alternator is probably a Hitachi with a built in regulator. Built in or not is another important question. If you want better battery charging management you might consider an alternator sans the regulator and install a smart regulator. Another thing you want to consider is the alternator output, you do not want a 100 amp alternator for an engine of that size for everytime it kicks in you would lose 15 to 25 percent of your engine horses.

There are many aftermarket 'marine' alternators, Balmar and Ample Power to name two. I know of a company down in the Marathon region of the keys who supposedly builds very inexpensive replacements, I dont have any information handy but would be happy to get his number if you ask.

Lastly, if the boat is up for the season you might cosider having yours rebuilt, always a cheaper alternative to new if done by a reputable shop.

Good luck in any case.
Captain Bruce
Reply With Quote Quick reply to this message Share with Facebook
  #4  
Old 10-30-2007
Junior Member
 
Join Date: Dec 2001
Location: Sacramento
Posts: 11
Thanks: 0
Thanked 0 Times in 0 Posts
Rep Power: 0
kenstuber is on a distinguished road
If it would help with your problem, I have a used but good Yanmar 35-amp alternator that came off my 2QM20 available.

Regards, Ken
Reply With Quote Quick reply to this message Share with Facebook
  #5  
Old 10-30-2007
Senior Member
 
Join Date: Sep 2007
Posts: 171
Thanks: 0
Thanked 0 Times in 0 Posts
Rep Power: 8
hertfordnc is on a distinguished road
More than likely it was a direct short.

The boat is new to me. I had one battery. I added a second battery. Some time after that I discovered the alternator was not charging. SOmetime after that I was finding my way in the dark to an anchorage. THe next day I got to looking over everything and found a black battery wire that really should have been a red wire.

There was no voltage at the alternator. I suspect i fried the VR. I can probably get it rebuilt. That's why I want to slap some cheap marine alt in ther and rebuild the first one and have a spare or maybe even mount both of them.
Reply With Quote Quick reply to this message Share with Facebook
  #6  
Old 10-30-2007
Senior Member
 
Join Date: Jun 2006
Posts: 2,394
Thanks: 0
Thanked 1 Time in 1 Post
Rep Power: 11
cardiacpaul is a jewel in the rough cardiacpaul is a jewel in the rough cardiacpaul is a jewel in the rough
welcome to the joys of boat ownership!
take your alternator to a repair shop, have them suggest a replacement, and have them rebuild yours.
__________________
We are not primarily on earth to see through one another, but to see one another through

Some people are like slinkies: not really good for anything... but you can't help laughing when you push them down the stairs
Reply With Quote Quick reply to this message Share with Facebook
  #7  
Old 10-30-2007
HoffaLives's Avatar
Senior Member
 
Join Date: Feb 2007
Location: my mother's basement
Posts: 531
Thanks: 0
Thanked 0 Times in 0 Posts
Rep Power: 8
HoffaLives is on a distinguished road
A couple of things to know about factory alternators:
1) they are designed to only charge light-duty starting batteries, no more. If you have a deep-cycle house battery, it will sulfate it and reduce the charge capacity fairly quickly.
2) the amperage of the alternator should be approximately 1/3 the amp-hr rating of your battery system in order to keep everything fully charged. For example if you have or one day want 200 amp-hrs of house capacity, you should install an 80 amp alternator.

If you are using the alternator to charge a house deep cycle, to get the most life and capacity out of it you should get a regulator-free alternator and install a three stage smart regulator. A built-in simple regulator will not properly charge a deep cycle battery leading to the sulfation mentioned above.

You can replace the marine alternator with an automotive one at a fraction of the cost. You can also keep a spare diode pack and brushes aboard very cheaply.

It's important to NOT run the alternator output through the power/bank switch (the usual configuration). These switches are unreliable and if and when they go they will fry your alternator diodes. Also if anyone switches it when the engine is running the same can occur. It is much better to use a dual diode isolator to connect the alternator output directly to the batteries and just switch the battery output.

Rewire your system so that there is a direct cable ground from the alternator to the batteries and B+ output to diodes and batteries. Bad connections are the source of most alternator failures and it is not uncommon to have twenty or more connections between B+ output and the ground return through the engine block. You can reduce this to 6.
Reply With Quote Quick reply to this message Share with Facebook
  #8  
Old 10-30-2007
Senior Member
 
Join Date: Sep 2007
Posts: 171
Thanks: 0
Thanked 0 Times in 0 Posts
Rep Power: 8
hertfordnc is on a distinguished road
naahhh,

I can probalby rebuild it myself once I get it back in my hands but I left it on the boat 200 miles away. There are no such repair shops anywhere near me and I am a marginally competent aircraft electrician. I can probably figure this out with a little guidance from all you experienced boat folks.
Reply With Quote Quick reply to this message Share with Facebook
  #9  
Old 10-30-2007
Senior Member
 
Join Date: Sep 2007
Posts: 171
Thanks: 0
Thanked 0 Times in 0 Posts
Rep Power: 8
hertfordnc is on a distinguished road
Hoffa,

THat's exactly the sort of theretical info I was looking for. My replay above was to cardiacpaul. I didn't realize this thread was going to be so hot.

Don't you people have jobs? oh yeah, i'm at my job. I should do some work.

thanks
Reply With Quote Quick reply to this message Share with Facebook
  #10  
Old 10-30-2007
Junior Member
 
Join Date: Dec 2001
Location: Sacramento
Posts: 11
Thanks: 0
Thanked 0 Times in 0 Posts
Rep Power: 0
kenstuber is on a distinguished road
Regarding my used but good Yanmar alternator. Sailnet won't allow me to post my email address or reply to a PM, because they say I don't have enough posts. Oh well. Frustrating.

Ken
Reply With Quote Quick reply to this message Share with Facebook
Reply

Quick Reply
Message:
Options

By choosing to post the reply above you agree to the rules you agreed to when joining Sailnet.
Click Here to view those rules.

Register Now

In order to be able to post messages on the SailNet Community forums, you must first register.
Please enter your desired user name, your email address and other required details in the form below.
Please note: After entering 3 characters a list of Usernames already in use will appear and the list will disappear once a valid Username is entered.
User Name:
Password
Please enter a password for your user account. Note that passwords are case-sensitive.
Password:
Confirm Password:
Email Address
Please enter a valid email address for yourself.
Email Address:

Log-in

Human Verification

In order to verify that you are a human and not a spam bot, please enter the answer into the following box below based on the instructions contained in the graphic.




Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)
 
Thread Tools

 
Posting Rules
You may post new threads
You may post replies
You may post attachments
You may edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is On



All times are GMT -4. The time now is 08:41 PM.

Add to My Yahoo!         
Powered by vBulletin® Version 3.8.7
Copyright ©2000 - 2014, vBulletin Solutions, Inc.
SEO by vBSEO 3.6.1
(c) Marine.com LLC 2000-2012

The SailNet.com store is owned and operated by a company independent of the SailNet.com forum. You are now leaving the SailNet forum. Click OK to continue or Cancel to return to the SailNet forum.