Volvo D3 24v Alternator not charging


 

Ralph, 

I am not exactly sure what you are asking, so I'll explain what I think you're asking. 

The 24v Matervolt 110 Alpha alternator requires excitement by 24 volts, or will self excite with higher rpm, and once excited at high rpm it will stay that way., 

As you know, the D3 has a 12v ignition circuit. The 12v ignition circuit closes a relay switch that is connected to the 24v house bank. Once this switch is closed, 24v goes to the 24v alternator excite circuit, causing the alternator to begin charging.

So, these are the possibilities (in order of probability):
  1. Some mechanic who doesn't understand this has disconnected everything to silence the alternator alarm. The mechanic then charges the owner 250 euros and says all is fixed. I know of at least 10 cases where this happened.
  2. The relay (pictured below, circled in green) needs replacing. 
  3. There is a bad or loose wire somewhere.
  4. Maybe the alternator has an internal problem
  5. Maybe the Alpha Pro regulator (pictured below, circled in red) has a problem.
  6. Maybe I read too much into your question
I hope this helps and thanks to Arno for the photo.

Bill
image.png

CW Bill Rouse Amel Owners Yacht School
720 Winnie, Galveston Island, Texas 77550 
   

On Sat, Apr 9, 2022, 11:10 Ralph Heilig <ralph.heilig@...> wrote:
Hi Bill,

thanks for your Information. 

This was and is a Diruptor Problem that only occured once (three years ago) after motoring 3 days non stop with higher rpm. In my case the Diruptor was so "preheated" that after 10 min use of the Watermaker the fuse triggered. Afer arrival and cool down, all back ok....it also never happend again, since I never did this kind of long high rpm crusing...

I had a complete raw water check. All ok. Last year I had to clean and decalc the Onan heat exchanger.

But do you have any Idea how to get the 24v Alternater charging at idle? That's a little annyoing...I don't know it it was always like this or when it started, but I recogniced it about two years ago.

Thanks,
Ralph


Ralph Heilig
 

Thanks Bill,

I will check next week. 

The symptoms I have:

When I start the Engine and it Idles at 700 rpm, the Link 10 Batterie Monitor shows no charging (no running bar)
It starts charging when rpm is increased to about 800 rpm, then working fine. Link 10 shows charging (running bar)
When going back under 800 rpm then stopping charging ( no running bar)

It's not a big problem, since on cruise It's working fine and at anchorage I use the generator. I was just wondering if I am the only one and something is wrong or if it's normal. As I wrote, I recogniced this behavior two or three years ago...

Thanks,
Ralph


 

It is possible that by design, the alternator/regulator may not send any output at 800 rpm

Best,

CW Bill Rouse 
Amel Owners Yacht School
+1 832-380-4970 | brouse@...
720 Winnie, Galveston Island, Texas 77550 
www.AmelOwnersYachtSchool.com 
Yacht School Calendar: www.preparetocastoff.blogspot.com/p/calendar.html


   

On Sat, Apr 9, 2022, 13:07 Ralph Heilig <ralph.heilig@...> wrote:
Thanks Bill,

I will check next week. 

The symptoms I have:

When I start the Engine and it Idles at 700 rpm, the Link 10 Batterie Monitor shows no charging (no running bar)
It starts charging when rpm is increased to about 800 rpm, then working fine. Link 10 shows charging (running bar)
When going back under 800 rpm then stopping charging ( no running bar)

It's not a big problem, since on cruise It's working fine and at anchorage I use the generator. I was just wondering if I am the only one and something is wrong or if it's normal. As I wrote, I recogniced this behavior two or three years ago...

Thanks,
Ralph


Bruno COTTE
 

Yes it is normal . 

Envoyé de mon iPhone

Le 9 avr. 2022 à 19:23, CW Bill Rouse <brouse@...> a écrit :


It is possible that by design, the alternator/regulator may not send any output at 800 rpm

Best,

CW Bill Rouse 
Amel Owners Yacht School
+1 832-380-4970 | brouse@...
720 Winnie, Galveston Island, Texas 77550 
www.AmelOwnersYachtSchool.com 
Yacht School Calendar: www.preparetocastoff.blogspot.com/p/calendar.html


   

On Sat, Apr 9, 2022, 13:07 Ralph Heilig <ralph.heilig@...> wrote:
Thanks Bill,

I will check next week. 

The symptoms I have:

When I start the Engine and it Idles at 700 rpm, the Link 10 Batterie Monitor shows no charging (no running bar)
It starts charging when rpm is increased to about 800 rpm, then working fine. Link 10 shows charging (running bar)
When going back under 800 rpm then stopping charging ( no running bar)

It's not a big problem, since on cruise It's working fine and at anchorage I use the generator. I was just wondering if I am the only one and something is wrong or if it's normal. As I wrote, I recogniced this behavior two or three years ago...

Thanks,
Ralph


Bill Kinney
 

It is normal that alternator charging at 800RPM is not significant.  It is expected and typical.

At an engine RPM of 700 or 800 the alternator is barely turning fast enough to generate power.  It takes an engine RPM of about 1200 to 1500 before the alternator actually generates anywhere near its rated output.  It’s a complicated issue, but especially if the batteries are near full you can expect very little output from the alternator at idle RPM on the main engine.

Bill Kinney
SM160, Harmonie
Ragged Island, Bahamas


rossirossix4
 

Bill,
Let me piggy-bak on that.  At low RPMs the alternators are not well cooled by their fans.  Even though the alternator is always rotating at a faster RPM than the engine, depleted batteries (and especially lithium batteries) or high amp draws can put a high load on them causing heat that is not well dissipated by the alternator's fan when it is at low rpm.  Related--when we are maneuvering (with low engine RPM) in a dock using our bow thruster or using the windlass to anchor or de-anchor, whenever we shift the engine into neutral we increase the engine speed to 1500 it ony takes a second to throttle down before we shift into forward or reverse.
Bob     KAIMI SM429