Alternator has stopped working

[170968]

I just started my engine and my alternator seems to be broken.

 

There is no current coming from it into my starter battery, and it is not heating up at all. Also, my rev counter isn't working. Does the rev counter rely on the alternator?

 

Is there anything I can do (tests or whatever), or should I just look for a new one?

 

Does anything else rely on the alternator? Am I safe running the engine in this state?

 

I expect this is due to me using it to charge lithium batteries. I did test the temperature a few times and thought it was OK (about 90C), but I guess it could  be a large strain on an old alternator. Lesson learned.

[MtB]

17 minutes ago, 170968 said:

I expect this is due to me using it to charge lithium batteries. I did test the temperature a few times and thought it was OK (about 90C), but I guess it could  be a large strain on an old alternator. Lesson learned.

 

Almost certainly the LiFePO4 battery killed your alternator but others will be along to help you test and find out for sure.

 

I doubt is was overheating that killed it. Assuming you have a 'drop in' LiFePO4 battery the built in BMS that 'protects' the battery probably disconnected it from the alternator when it got to 100% charged. This kills alternators. They often forget to mention this....

 

 

And yes the alternator provides the speed info for the rev counter. 

 

What make and model of alternator it it? Or post a photo....

 

[Tony Brooks]

1. Yes, the rev counter needs pulses from the alternator, no charge = no pulses.

 

2. "it is not heating up at all. Do you mean the temperature gauge stays at zero or that you have felt the engine/hoses, and they are still stone-cold?  I suspect the former.

 

3. If it is the gauge not rising, then it suggests to me that the feed to/from the ignition switch has failed. If it has then the gauges will not work and in mots cases the alternator will not energise.

 

4. 90c should be fine for an automotive alternator. may sources suggest you have about 50c headroom at that.

 

Many boats have a fuse hidden close to the main engine harness or under a cover on the actual engine. If this has blown then it is consistent with your symptoms, but before you do anything else make sure the alternator drive belt is properly tensioned and in good order.

 

Do you have a multimeter and know how to set it up and use it to check for voltage at various places?

 

What make and model of engine? What make and model of the alternator? Photos will help if you do not know.

 

For other members:- I have, at this time, discounted the harness multiplugs and the alternator based on the comment about the engine not warming up. With more info, it should become easier to give better suggestions and fault-finding procedure.

 

 

[ditchcrawler]

First thing, Does the "Ignition" light come on when you switch the engine on, if so does it go out when you run the engine?

[David Mack]

19 minutes ago, Tony Brooks said:

based on the comment about the engine not warming up.

Engine not warming up, or alternator staying stone cold?

[Tony Brooks]

Just now, David Mack said:

Engine not warming up, or alternator staying stone cold?

 

Good question, we must wait for the OP to respond.

[MtB]

9 minutes ago, David Mack said:

Engine not warming up, or alternator staying stone cold?

 

I read it as the alternator staying atone cold.

 

My money remains on his battery BMS disconnecting at 100% whilst drawing a full alternator charge current and making it choke on its diodes. 

[Alan de Enfield]

It appears that he monitors the alternator temperature because he is charging lithiums, so my reading is that the alternator is not getting hot.

 

I reckon MTB has sorted it.

 

The battery BMS shut down and the alternator just imploded.

[David Mack]

4 minutes ago, MtB said:

 

My money remains on his battery BMS disconnecting at 100% whilst drawing a full alternator charge current and making it choke on its diodes. 

Which is presumably why some fit a lead acid starter battery in parallel with a domestic Lithium, so there is always a battery connected to the alternator. (And if you do that do you have to go against the normal advice to connect the alternator to the domestic bank?)

[MtB]

3 minutes ago, Alan de Enfield said:

It appears that he monitors the alternator temperature because he is charging lithiums, so my reading is that the alternator is not getting hot.

 

I reckon MTB has sorted it.

 

The battery BMS shut down and the alternator just imploded.

 

 

Indeed. 

 

So dear OP, the question now becomes "what controls have you installed to protect your alternator when the BMS disconnects from it at 100% SoC?

 

My fear is your answer will be "None", or "Do what, mate?", or something along those lines. 

[170968]

1 hour ago, MtB said:

 

Almost certainly the LiFePO4 battery killed your alternator but others will be along to help you test and find out for sure.

 

I doubt is was overheating that killed it. Assuming you have a 'drop in' LiFePO4 battery the built in BMS that 'protects' the battery probably disconnected it from the alternator when it got to 100% charged. This kills alternators. They often forget to mention this....

 

 

And yes the alternator provides the speed info for the rev counter. 

 

What make and model of alternator it it? Or post a photo....

 

 

The alternator is always connected to the starter battery, so it isn't a disconnect problem. See below for make/model.

 

 

 

51 minutes ago, Tony Brooks said:

1. Yes, the rev counter needs pulses from the alternator, no charge = no pulses.

 

2. "it is not heating up at all. Do you mean the temperature gauge stays at zero or that you have felt the engine/hoses, and they are still stone-cold?  I suspect the former.

 

3. If it is the gauge not rising, then it suggests to me that the feed to/from the ignition switch has failed. If it has then the gauges will not work and in mots cases the alternator will not energise.

 

4. 90c should be fine for an automotive alternator. may sources suggest you have about 50c headroom at that.

 

Many boats have a fuse hidden close to the main engine harness or under a cover on the actual engine. If this has blown then it is consistent with your symptoms, but before you do anything else make sure the alternator drive belt is properly tensioned and in good order.

 

Do you have a multimeter and know how to set it up and use it to check for voltage at various places?

 

What make and model of engine? What make and model of the alternator? Photos will help if you do not know.

 

For other members:- I have, at this time, discounted the harness multiplugs and the alternator based on the comment about the engine not warming up. With more info, it should become easier to give better suggestions and fault-finding procedure.

 

 

 

It's the alternator which isn't heating up. The engine is fine.

The alternator does have 12V and I believe is "energised".

I do have a multimeter and can read voltages.

 

 

33 minutes ago, ditchcrawler said:

First thing, Does the "Ignition" light come on when you switch the engine on, if so does it go out when you run the engine?

 

Yes the battery light comes on but doesn't go off like it should when it's charging from the alternator.

 

Thanks for all the replies. Hope that clears things up a bit.

Oh and the engine is a Nanni. I'll get the book out and tell you which model in a minute.

 

Edit: It is a Nanni 4.220 HE

Edited March 15, 2023 by 170968

[Tony Brooks]

Thanks, in that case I think it is taking it off time and get it tested.

[170968]

6 minutes ago, Tony Brooks said:

Thanks, in that case I think it is taking it off time and get it tested.

 

OK, thanks.

 

I notice the belt which feeds it goes around 3 pulleys. Is one of these the engine coolant pump and therefore I can't run the engine without it being connected?

[MtB]

23 minutes ago, 170968 said:

The alternator is always connected to the starter battery, so it isn't a disconnect problem. See below for make/model.

 

 

In that case I agree, it can't be a disconnection problem provided you are sure about that.

 

 

 

10 minutes ago, 170968 said:

 

OK, thanks.

 

I notice the belt which feeds it goes around 3 pulleys. Is one of these the engine coolant pump and therefore I can't run the engine without it being connected?

 

Yes that will be the case. 

 

I think from the symptoms presented Tony is of the view the alternator has failed and it won't be repairable it in-situ, so you may as well take it off now and take it to a repair shop than mess about trying to diagnose it more finely, then taking it off and to a repair shop!

 

 

[MoominPapa]

From experience, I'd take a guess at diode failure because it's been working hard. Alternators in boats, especially with LiFePO4 batteries work really hard and hot and the diodes are the first thing to go. It's normally only one though, which makes the alt noisy and reduces power, rather than stopping it completely.

 

It's worth carrying a spare alternator, they are not very expensive. When you have a failure change to the spare and get the faulty fixed or fix it yourself at leisure.

 

You can run the engine with the faulty alternator on place and belt fitted, but not if you've remove it and the belt.

 

MP

[ditchcrawler]

2 minutes ago, MtB said:

I think from the symptoms presented Tony is of the view the alternator has failed and it won't be repairable it in-situ, so you may as well take it off now and take it to a repair shop than mess about trying to diagnose it more finely, then taking it off and to a repair shop!

 

 

Before I did that I would try flashing it between the ign. connection and the 12 volt output just to make sure its not a problem with the ignition circuit. 

[170968]

8 minutes ago, MoominPapa said:

It's worth carrying a spare alternator, they are not very expensive. When you have a failure change to the spare and get the faulty fixed or fix it yourself at leisure.

 

Yes I'll definitely order a new one and do as you say

 

8 minutes ago, ditchcrawler said:

Before I did that I would try flashing it between the ign. connection and the 12 volt output just to make sure its not a problem with the ignition circuit. 

 

Perhaps you're right. I was just fiddling with it (testing voltage) and it started working: 14.4v at the battery, the battery/ignition light went out, and the rev counter is working. However, I turned the engine off and on a couple of times to be sure and now whilst everything else is working, the battery/ignition light is flickering and dimming, rather than going out entirely. What does this point to?

 

[nicknorman]

16 minutes ago, 170968 said:

 

Yes I'll definitely order a new one and do as you say

 

 

Perhaps you're right. I was just fiddling with it (testing voltage) and it started working: 14.4v at the battery, the battery/ignition light went out, and the rev counter is working. However, I turned the engine off and on a couple of times to be sure and now whilst everything else is working, the battery/ignition light is flickering and dimming, rather than going out entirely. What does this point to?

 

Could be the alternator slip ring brushes. If you remove the drive belt, turn on the ignition, and rotate the alternator by hand, the warning light should be on steady. If it flickers, it means the brushes are worn out and barely touching the slip rings. If rotating the alternator doesn’t make a difference I would just try wiggling the wiring between the engine and the control panel to see if you get a reaction in the flickering. Could of course be something to do with a multi-way connector between the engine wiring and the panel, which is often found on modern engines, although I have no specific knowledge of a Nanni.

[170968]

2 minutes ago, nicknorman said:

Could be the alternator slip ring brushes. If you remove the drive belt, turn on the ignition, and rotate the alternator by hand, the warning light should be on steady. If it flickers, it means the brushes are worn out and barely touching the slip rings. If rotating the alternator doesn’t make a difference I would just try wiggling the wiring between the engine and the control panel to see if you get a reaction in the flickering. Could of course be something to do with a multi-way connector between the engine wiring and the panel, which is often found on modern engines, although I have no specific knowledge of a Nanni.

 

Thanks, I'll give it a try and report back. Won't be for a while though as I need to go out.

[Tracy D'arth]

Check all the wiring connections near where you were fiddling to see if one is loose.

[Tony Brooks]

55 minutes ago, ditchcrawler said:

Before I did that I would try flashing it between the ign. connection and the 12 volt output just to make sure its not a problem with the ignition circuit. 

 

I am not sure, but I got the impression that Leece-Nevills were six diode machines, and if so doing what you suggest (correctly for a nine diode machine) would just put the warning lamp out during the flashing. Six diode machines normally have an ignition feed separate from the warning lamp for excitation. Often marked "ign". That would be the one to flash.

 

28 minutes ago, nicknorman said:

Could be the alternator slip ring brushes. If you remove the drive belt, turn on the ignition, and rotate the alternator by hand, the warning light should be on steady. If it flickers, it means the brushes are worn out and barely touching the slip rings. If rotating the alternator doesn’t make a difference I would just try wiggling the wiring between the engine and the control panel to see if you get a reaction in the flickering. Could of course be something to do with a multi-way connector between the engine wiring and the panel, which is often found on modern engines, although I have no specific knowledge of a Nanni.

 

I agree, except the photo does not look as if the alternator is old enough to have worn its brushes. Agree it is worth waggling all connections on and between alternator and ignition switch.

[Tony Brooks]

Been Googling. I knew there was something a bit odd about at least some Leece-Nevill alternators, and it seems at least some are self exiting - that is need no warning lamp or ignition feed to energise the machine on start up. In one manual, there was a great big black warning not to flash to the warning lamp terminal or serious damage will occur.

 

Unfortunately, I could not find any info on the OP's alternator in English, so I don't know if any of this is relevant. I think it would be safer to get it off and taken to a specialist for testing. If the OP gives his approximate location, someone may be able to suggest a suitable place. I would not let a canal engineer or boatyard do it unless I was sure they knew Leece-Nevill alternators and how they work.

I don't know if @Sir Nibble is still around and is willing to help on this specific machine. (photo with model number above.)

[170968]

2 hours ago, Tony Brooks said:

 

I am not sure, but I got the impression that Leece-Nevills were six diode machines, and if so doing what you suggest (correctly for a nine diode machine) would just put the warning lamp out during the flashing. Six diode machines normally have an ignition feed separate from the warning lamp for excitation. Often marked "ign". That would be the one to flash.

 

 

I agree, except the photo does not look as if the alternator is old enough to have worn its brushes. Agree it is worth waggling all connections on and between alternator and ignition switch.

 

What exactly is this "flashing" of which you speak?

[MtB]

4 minutes ago, 170968 said:

 

What exactly is this "flashing" of which you speak?

 

I've been wondering the same. But I think it is slang or shorthand for taking a wire from battery +ve straight to the field terminal to bypass all the existing 'ignition switch' circuitry. 

 

 

 

Edited March 15, 2023 by MtB

[170968]

1 hour ago, Tony Brooks said:

If the OP gives his approximate location, someone may be able to suggest a suitable place.

 

Great idea. I am currently around Braunston and will be for a while.

 

Something which I noticed earlier and only just thought of as relevant, is that while the engine was running, and the battery light was dimming/flickering, I switched my lithium bank into the circuit, and the current was steady at around 30 amps, which is what I would have expected at that RPM. I was wondering if this would be the case if the problem was worn out brushes? My uneducated brain thinks no.

 

I havent had time to do any waggling yet. Probably do it tomorrow.

Edited March 15, 2023 by 170968