Cruisers Forum
 


Join CruisersForum Today

Reply
  This discussion is proudly sponsored by:
Please support our sponsors and let them know you heard about their products on Cruisers Forums. Advertise Here
 
Thread Tools Search this Thread Rate Thread Display Modes
Old 01-09-2019, 19:19   #1
Registered User

Join Date: Feb 2018
Posts: 26
Alternator help needed

Dear All,

I have the stock 80A Hitachi alternator on my Yanmar 4JH2-HTE.
The alternator stopped working/no output at all.

Here is my findings:
- When ignition key is at "ON" position, the ALT/charge warning light on the panel doesn't come on. (it used to light up before engine start, at key ON position, and it should)
- After the engine start, the ALT/charge warning light doesn't come on, plus there is no output on the alternator. (it should light up if/when there is a charging issue)
- Before & after the engine start, I can read the same voltage as my battery at the ALT output terminals: positive and GND.
- I checked the two ALT/charge warning lights (one on the panel, one behind the panel) and they are both fine.

What would you suggest for further testing to identify the problem?

Many thanks.
__________________

barunal is offline   Reply With Quote
Old 01-09-2019, 19:40   #2
Registered User

Join Date: Aug 2019
Posts: 90
Re: Alternator help needed

As silly as this sounds, in some charging systems when the warning light on the panel burns out the charging system no longer works due to the bulb being burnt out. The circuit needs the bulb to function properly. Pull the bulb out and check to see if it is good. If you have a spare, just stick the spare in the bulb socket and go from there.
__________________

Shenandoah52 is offline   Reply With Quote
Old 01-09-2019, 19:42   #3
Registered User

Join Date: Feb 2018
Posts: 26
Re: Alternator help needed

Hi Shenandoah52.
Thank you for your input.
I checked both bulbs and they are fine. (one on the panel, and the other one hiding behind the panel)
barunal is offline   Reply With Quote
Old 01-09-2019, 20:34   #4
Registered User
 
wingssail's Avatar

Join Date: Jan 2010
Location: On Vessel WINGS, wherever there's an ocean, currently in Mexico
Boat: Serendipity 43
Posts: 1,376
Send a message via AIM to wingssail Send a message via Skype™ to wingssail
Re: Alternator help needed

Quote:
Originally Posted by barunal View Post
Dear All,

I have the stock 80A Hitachi alternator on my Yanmar 4JH2-HTE.
The alternator stopped working/no output at all.

Here is my findings:
- When ignition key is at "ON" position, the ALT/charge warning light on the panel doesn't come on. (it used to light up before engine start, at key ON position, and it should)
- After the engine start, the ALT/charge warning light doesn't come on, plus there is no output on the alternator. (it should light up if/when there is a charging issue)
- Before & after the engine start, I can read the same voltage as my battery at the ALT output terminals: positive and GND.
- I checked the two ALT/charge warning lights (one on the panel, one behind the panel) and they are both fine.

What would you suggest for further testing to identify the problem?

Many thanks.
The stock alternator has a wire for the lamp (L). If it is not lighting then either you have no power to the field (F, assuming that the internal regulation is still present) or the alternator is burned out internally.

If you have external regulation then either there is no power to that device or it is burned out.
__________________
Sailing is a sport, an athletic activity, not a sedentary one.
Fred Roswold-Fred & Judy, SV Wings, Mexico
http://wingssail.blogspot.com/
wingssail is offline   Reply With Quote
Old 01-09-2019, 20:38   #5
Registered User

Join Date: Aug 2019
Posts: 90
Re: Alternator help needed

My apologies, I see you had that in the original post. A good reason to check the warning light circuit, bulb, socket, and wires, is because your alternator has 3 circuits 120 degrees apart as it spins and if one fails the other two phases will still show it's charging. Same with two out. It won't charge for diddly, but it will send voltage to the bulb. No light could mean a totally bad alternator or a bad warning light bulb or circuit.

It's also the cheapest fix so a good one to look before before you start throwing money at the problem. A multi meter is your friend here, but you may be well past that already I have no idea. Is the warning light circuit good?
Shenandoah52 is offline   Reply With Quote
Old 01-09-2019, 20:54   #6
Registered User

Join Date: Jun 2013
Location: canada
Posts: 2,769
Re: Alternator help needed

Normally yanmar have 2 small wires on the alt. Red and blue. Both should have 12v when the key is on. Check that. One is lamp and one is ignition.

If you have 12v on both wires and the main pos wire. The alt is probably shot.
smac999 is offline   Reply With Quote
Old 01-09-2019, 20:57   #7
Registered User

Join Date: Feb 2018
Posts: 26
Re: Alternator help needed

Shenandoah52; bulbs are fine but I should do further checking on that circuit.

Smac999, thanks for the input. Both small wires (red & blue) have 12v on them when the key is on.
barunal is offline   Reply With Quote
Old 02-09-2019, 02:50   #8
Senior Cruiser
 
GordMay's Avatar

Cruisers Forum Supporter

Join Date: Mar 2003
Location: Thunder Bay, Ontario - 48-29N x 89-20W
Boat: (Cruiser Living On Dirt)
Posts: 36,820
Images: 241
Re: Alternator help needed

Alternator Testing
https://dam-assets.fluke.com/s3fs-pu...00_ENG_A_W.PDF
__________________
Gord May
"If you didn't have the time or money to do it right in the first place, when will you get the time/$ to fix it?"



GordMay is offline   Reply With Quote
Old 02-09-2019, 04:15   #9
Certifiable Refitter/Senior Wannbe
 
Wotname's Avatar

Join Date: Jan 2008
Location: South of 43 S, Australia
Boat: C.L.O.D.
Posts: 10,144
Re: Alternator help needed

Quote:
Originally Posted by barunal View Post
Dear All,

I have the stock 80A Hitachi alternator on my Yanmar 4JH2-HTE.
The alternator stopped working/no output at all.

Here is my findings:
- When ignition key is at "ON" position, the ALT/charge warning light on the panel doesn't come on. (it used to light up before engine start, at key ON position, and it should)............

What would you suggest for further testing to identify the problem?

Many thanks.
IMO, troubleshoot the above first.
Until the ALT warning light come on initially, all else is wasted effort. The circuit is quite straight forward and if all the external components test satisfactory, the fault most likely will be in the internal regulator. If the regulator is shot, that would explain why the alternator is no outputting.

The attached circuit is from the 4JH2 manual and is for the 55 amp Hitachi alternator - I suspect the 80 amp will be the same.
Attached Thumbnails
Click image for larger version

Name:	4JH2 Alternator.png
Views:	74
Size:	170.6 KB
ID:	199036   Click image for larger version

Name:	4JH2 Alternator 2.png
Views:	50
Size:	261.7 KB
ID:	199037  

__________________
All men dream: but not equally. Those who dream by night in the dusty recesses of their minds wake in the day to find it was vanity: but the dreamers of the day are dangereous men, for they may act their dreams with open eyes, to make it possible. T.E. Lawrence
Wotname is offline   Reply With Quote
Old 02-09-2019, 17:52   #10
Registered User

Join Date: Feb 2018
Posts: 26
Re: Alternator help needed

Wotname, thank you very much for the input.
I will go through the warning light circuit first.
barunal is offline   Reply With Quote
Old 02-09-2019, 19:35   #11
Registered User

Join Date: Jun 2013
Location: canada
Posts: 2,769
Re: Alternator help needed

If there is 12v at the alt on the lamp wire. Then the problem is inside the alt. Pull it off and take to an alt shop for testing and repair.
smac999 is offline   Reply With Quote
Old 02-09-2019, 19:47   #12
Registered User

Join Date: Feb 2018
Posts: 26
Re: Alternator help needed

smac999; well noted, thank you.
barunal is offline   Reply With Quote
Old 02-09-2019, 20:56   #13
Certifiable Refitter/Senior Wannbe
 
Wotname's Avatar

Join Date: Jan 2008
Location: South of 43 S, Australia
Boat: C.L.O.D.
Posts: 10,144
Re: Alternator help needed

Quote:
Originally Posted by smac999 View Post
If there is 12v at the alt on the lamp wire. Then the problem is inside the alt. Pull it off and take to an alt shop for testing and repair.
Quote:
Originally Posted by barunal View Post
smac999; well noted, thank you.
To be pedantic, smac999 is correct when the alternator is stationary; if the alternator is spinning and working normally, there will 12V on the lamp wire.
__________________
All men dream: but not equally. Those who dream by night in the dusty recesses of their minds wake in the day to find it was vanity: but the dreamers of the day are dangereous men, for they may act their dreams with open eyes, to make it possible. T.E. Lawrence
Wotname is offline   Reply With Quote
Old 02-09-2019, 21:27   #14
Registered User

Join Date: Feb 2018
Posts: 26
Re: Alternator help needed

When the ignition key is ON, I get 12V on both red & blue wires that come in a T-plug to connect to the alternator.
However, the charge warning light is still off by then, which should light up.
Warning light stays off after the start as well, and there is no output on the ALT.
barunal is offline   Reply With Quote
Old 02-09-2019, 21:35   #15
Certifiable Refitter/Senior Wannbe
 
Wotname's Avatar

Join Date: Jan 2008
Location: South of 43 S, Australia
Boat: C.L.O.D.
Posts: 10,144
Re: Alternator help needed

Quote:
Originally Posted by barunal View Post
When the ignition key is ON, I get 12V on both red & blue wires that come in a T-plug to connect to the alternator.
However, the charge warning light is still off by then, which should light up.
Warning light stays off after the start as well, and there is no output on the ALT.
Is that with the T-plug connected to or disconnected from the alternator?
__________________

__________________
All men dream: but not equally. Those who dream by night in the dusty recesses of their minds wake in the day to find it was vanity: but the dreamers of the day are dangereous men, for they may act their dreams with open eyes, to make it possible. T.E. Lawrence
Wotname is offline   Reply With Quote
Reply

Tags
alternator

Thread Tools Search this Thread
Search this Thread:

Advanced Search
Display Modes Rate This Thread
Rate This Thread:

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off


Similar Threads
Thread Thread Starter Forum Replies Last Post
Help needed with alternator replacement on a Yanmar 2gm Kidd Karibe Engines and Propulsion Systems 15 03-01-2020 15:32
alternator regulators vs alternator to battery charger tml Electrical: Batteries, Generators & Solar 12 01-05-2017 12:35
High Rated Alternator with Alternator to Battery Charger Rumbero Electrical: Batteries, Generators & Solar 113 18-07-2014 05:29
Help Needed! - Wiring Alternator to Charge House Batteries cgaskell Electrical: Batteries, Generators & Solar 6 04-04-2010 15:09

Advertise Here


Copyright 2002- Social Knowledge, LLC All Rights Reserved.

All times are GMT -7. The time now is 07:18.


Google+
Powered by vBulletin® Version 3.8.8 Beta 1
Copyright ©2000 - 2020, vBulletin Solutions, Inc.
Social Knowledge Networks
Powered by vBulletin® Version 3.8.8 Beta 1
Copyright ©2000 - 2020, vBulletin Solutions, Inc.

ShowCase vBulletin Plugins by Drive Thru Online, Inc.