Charging problems - warning buzzer sounds

[DJW]

Hi

 

Im currently marooned on the Thames while the water levels (hopefully) drop to navigable levels. I'm having to run the engine to charge the batteries and have noticed that the battery charging warning light and buzzer have started coming on weakly while the engine is running.

 

From start up the buzzer/light are on fully. Applying some revs gets the alternator to kick in and the light/buzzer go off. This has always been the case. What's new is that after a while the buzzer/light then come on very weakly but the pitch of the buzzer & brightness of the light increase with the engine revs. The fault was intermittent but seems to be becoming more persistent.

 

I've measured the voltage at the alternator and it's a decent 13.5-14 V (hard to get a consistent read out due to the engine vibrating). The voltmeter on the control panel reads a little over 12v (normally reads between 12 and 14 when cruising). I've tried running the engine under load (whilst moored still) but this doesnt seeem to affect the buzzer/light issue.

 

I have a Vetus M4.17 with standard (50A? i think) alternator, charging 5 domestic and 1 starter battery via a split charging system. I also have a Sterling battery management (charger, inverter) system.

 

Does anyone know how to resolve this? It appears to be a faulty connection somewhere but there are so many wires going to the tachometer/warning light panel that I don't really know where to start!

 

Thanks

[Keeping Up]

This sounds like the classic symptom of the alternator voltage trying to get above the battery voltage. The more you rev the engine, the more the alternator voltage rises, and the brighter the lamp (whose other side is tied to the battery positive) will glow. I can think of two likely causes - maybe others can increase your choice to three or more.

 

One possibility is a poor connection in the main charging feed somewhere between the alternator and the battery (including possibly the split charge relay). I used to get this symptom and it took me months to track it down to simply an overheating spade connection to the alternator output. The best way to check this out is probably to use your meter with one probe on the battery positive and the other on the alternator output terminal.

 

The other likely possibility is that a diode in the alternator has failed. This is harder to measure with a meter; but a reduction in the maximum output is usually the best clue, do you have an ammeter?

[DJW]

Sorry, just checked the alternator voltage again and its about 12.7. That roughly agrees with the control panel volt meter reading and the reading on the fuse panel inside.

 

Seems a bit low to me and lower than when I measured it whilst charging a couple of days ago

[Keeping Up]

Perhaps the batteries are a bit flatter at the moment? That could be why you're seeing a lower voltage.

 

But is there any obvious difference between the alternator output voltage (preferably measured on the alternator terminal rather than the cable) and the battery? If there is, find and fix it. If there isn't, suspect first that the alternator needs fixing or replacing (unless anyone else has any ideas?)

 

You could maybe take the alternator to a motor electrical place where they could test it, if you have one near you.

[bridge100]

My recent experiance with a similar problem, turned out to be alternator to battery main charge wire.

The terminals looked ok, but after i had thoroughly abraded and re crimpted them it solved theproblem.

Might be worth cleaning and crimping up all the conections

[Nickhlx]

My recent experiance with a similar problem, turned out to be alternator to battery main charge wire.

The terminals looked ok, but after i had thoroughly abraded and re crimpted them it solved theproblem.

Might be worth cleaning and crimping up all the conections

 

I would also second that last comment - and express surprise that there is only a 50 amp alternator charging 5 + 1 batteries.

 

On our boat we have a 50 amp alternator charging the starter and bow thruster batteries, and a Iskra 175 amp charging the

480 Ah domestic bank with some sort of voltage sensitive relay which combines the alternators and banks to provide

225 amps charge capability on 800 Ah total - we always have oodles of power and the batteries are usually at

between 75% and 100% charged...

 

I am not sure what replacement will easily fit your engine, or whether a second larger item could be grafted on easily, but

that would be a priority for me in that situation... The batteries will be taking hours and hours to fully charge properly, which I am sure you

don't or aren't able to run the engine for, so the bank will be ageing prematurely too, which is expensive and inconvenient too..

 

Nick

Edited May 5, 2012 by Nickhlx

[pistnbroke]

Keeping up ..please dont spread rubbish like this around

 

This sounds like the classic symptom of the alternator voltage trying to get above the battery voltage. The more you rev the engine, the more the alternator voltage rises, and the brighter the lamp (whose other side is tied to the battery positive) will glow.

The alternator voltge has to be above the battery voltage or it would never charge the battery !!!!!

 

He has diode problems on this alternator which makes the warning light glow it cannot come on if the brushes are faulty but may flash..

Edited May 5, 2012 by pistnbroke

[Keeping Up]

Keeping up ..please dont spread rubbish like this around

 

This sounds like the classic symptom of the alternator voltage trying to get above the battery voltage. The more you rev the engine, the more the alternator voltage rises, and the brighter the lamp (whose other side is tied to the battery positive) will glow.

The alternator voltge has to be above the battery voltage or it would never charge the battery !!!!!

 

He has diode problems on this alternator which makes the warning light glow it cannot come on if the brushes are faulty but may flash..

 

My post is not rubbish, I do know exactly what I am talking about, but there is rubbish in yours because the alternator voltage will not normally be significantly above the battery voltage.

 

The alternator's output voltage will normally be almost exactly equal to the battery voltage, unless there is a diode splitter involved. However if there is a significant resistance in the connection then there may be a noticeable voltage difference between the alternator and the battery. This is especially true if it is battery-sensed or if there is an external alternator controller, but a difference can still exist with a machine-sensed alternator. This difference may be enough to light the dashboard lamp dimly, and it will glow more brightly as the engine revs are increased.

 

I agree that it is more likely to be an alternator diode fault; but it is worth making a quick check for any voltage difference before going to the trouble of removing the alternator.

 

However I have NO intention in engaging in yet another electrical argument, I have had my say and that is enough.

[pistnbroke]

when the diodes go faulty there is an unbalance in the 3 phases which causes the alternator voltage to be lower during the faulty phase output and this causes the light to glow....

 

If the warning light is glowing its 99.9% chance its the diodes and 0.1% a faulty igniton switch...

Edited May 5, 2012 by pistnbroke

[by'eck]

when the diodes go faulty there is an unbalance in the 3 phases which causes the alternator voltage to be lower during the faulty phase output and this causes the light to glow....

 

If the warning light is glowing its 99.9% chance its the diodes and 0.1% a faulty igniton switch...

 

I would also agree with Nickhix/Keeping Up/bridge100 that it could be an alternator to battery connection. Lets face it alternator diodes are fairly rugged whilst many boat installations aren't, added to which is the electrically unfriendly environment.

[blodger]

I would also agree with Nickhix/Keeping Up/bridge100 that it could be an alternator to battery connection. Lets face it alternator diodes are fairly rugged whilst many boat installations aren't, added to which is the electrically unfriendly environment.

There's no mention of how hot the alternator is running at but hot alts cook their diodes as does some switching in and out of the alternator at the isolalator when it's running that many do by mistake rather tan intention

[pistnbroke]

put your finger on the stator laminations ...hot hot hot and vibrating ..diodes....or put a bulb from the wl terminal to the b on the alternator ..if its on it 100% diodes

Edited May 6, 2012 by pistnbroke

[DJW]

Thanks for the ideas. I had a few boaters who are also moored here over yesterday to check for obvious faults. Typically the problem disappeared when they were looking!

 

I will do some charging today (still can't move due to river conditions) and see if the problem reappears

[bottle]

Now while they were looking at it, did they 'wiggle' any connections ?

 

 

 

Not saying pistnbroke is right/wrong but you never know those lookers may well have found the problem.

Edited May 6, 2012 by bottle

[simon&jan]

Loose conections get hot , normally affecting female terminals , when they heat up they loose 'grip' on the male spade and so end up resting on it causing heat and resistance .

Edited May 6, 2012 by simon&jan

[Guest]

Hi

 

Im currently marooned on the Thames while the water levels (hopefully) drop to navigable levels. I'm having to run the engine to charge the batteries and have noticed that the battery charging warning light and buzzer have started coming on weakly while the engine is running.

 

From start up the buzzer/light are on fully. Applying some revs gets the alternator to kick in and the light/buzzer go off. This has always been the case. What's new is that after a while the buzzer/light then come on very weakly but the pitch of the buzzer & brightness of the light increase with the engine revs. The fault was intermittent but seems to be becoming more persistent.

 

I've measured the voltage at the alternator and it's a decent 13.5-14 V (hard to get a consistent read out due to the engine vibrating). The voltmeter on the control panel reads a little over 12v (normally reads between 12 and 14 when cruising). I've tried running the engine under load (whilst moored still) but this doesnt seeem to affect the buzzer/light issue.

 

I have a Vetus M4.17 with standard (50A? i think) alternator, charging 5 domestic and 1 starter battery via a split charging system. I also have a Sterling battery management (charger, inverter) system.

 

Does anyone know how to resolve this? It appears to be a faulty connection somewhere but there are so many wires going to the tachometer/warning light panel that I don't really know where to start!

 

Thanks

My friends 417 Vetus was showing similar symptoms about 3 years ago, and sorry to say it was a cooked alternator. I am fairly sure it will be a 90A unit as standard on the Vetus (mine is) but do check.

I think you would be wise to check all connections first though, I got similar symptoms on another (non vetus) engine when the inadequate split relay had gone resistive.

[Pretty Funked Up]

I'd also check/replace the belt. They arent expensive and if it doesnt cure it all youve done is gain a spare

[Guest]

I'd also check/replace the belt. They arent expensive and if it doesnt cure it all youve done is gain a spare

In the case of a Vetus, that is a very good point. The alternator really hammers the (seemingly inadequate) belt and I tend to change it each spring. I can tell when mine is knackered because the tacho reads too low.

[FrigateCaptain]

I'm getting similar problems, reading around 12.7 when charging and after having a new split charge relay to replace a multi switch. All connections are fine and new batterys fitted last week. Running a 70A alternator and 3 domestic plus a starter

[Keeping Up]

I'm getting similar problems, reading around 12.7 when charging and after having a new split charge relay to replace a multi switch. All connections are fine and new batterys fitted last week. Running a 70A alternator and 3 domestic plus a starter

 

Is your dashboard light behaving in EXACTLY the same way as the OP's, namely going out then glowing dimly but getting brighter as the engine revs increase?

[FrigateCaptain]

Ah, that's where it differs, no problem with dash lights

[blodger]

Ah, that's where it differs, no problem with dash lights

Are you saying that with time neither the starter battery or domestics are rising above 12.7?

[FrigateCaptain]

Are you saying that with time neither the starter battery or domestics are rising above 12.7?

Got back to the boat and batts where reading 12.4, after almost 3 hours of running no numbers over 12.7

[blodger]

Got back to the boat and batts where reading 12.4, after almost 3 hours of running no numbers over 12.7

Well the alt's not managing to charge then either for its own reasons or something amiss with the new wiring/relay. I presume the charge warning light is on at ignition on and then extinguishing with engine start? If it is then it is more likely the former but I would have expected the batts that are wired direct (not through the relay) to voltage rise.

 

If you have left in the selector/isolator and added the split charge relay perhaps the wiring wants re checking to see that the circuits are properly configured?

[Nickhlx]

Well the alt's not managing to charge then either for its own reasons or something amiss with the new wiring/relay. I presume the charge warning light is on at ignition on and then extinguishing with engine start? If it is then it is more likely the former but I would have expected the batts that are wired direct (not through the relay) to voltage rise.

 

If you have left in the selector/isolator and added the split charge relay perhaps the wiring wants re checking to see that the circuits are properly configured?

 

 

 

Do you trust the meter ?

 

Nick