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Alternator and wiring issues


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Afternoon all,

 

I have a Beta 43 with what I believe to be a 95 Amp domestic alternator and a Beta controller.

 

A few days ago, I started the engine to allow it to warm through while I de-moored and there was an occasional faint warning bleep and the domestic light on the panel was flickering. Once I unplugged the shoreline, all went back to normal no light flickering, no beeping so off we go with the intention to investigate later. As we were cruising, the faint beeping and flickering light re-appeared occasionally. With nowhere to pull over we continued and I assumed that It was the alternator failing and would need replacing.

 

Once moored up, I investigated to find that the engine loom was burnt out on a couple of wires on the domestic side right back to the panel, the damage being so bad that I have just had to replace the full engine loom right back to the panel! I was not able to 100% establish the cause, presuming that the loom had chaffed against something below the fuel filter as this appeared to be the source. (The new loom does not have the facility to connect to the heater plug relay, Beta say this is fine as we only have a 3 meter harness from the panel and all appears to be fine)

 

Since replacing the loom, all is fine, no warnings and both alternators are charging, however, when I start the engine with the shoreline plugged in (to provide us with hot water) The domestic alternator light is flashing in a consistent manner along with the warning beep. This never happened before the incident with the loom. I have spoken with Beat but they are not able to offer an explanation.

 

Has anyone come across this before? 

 

Any thoughts?

 

Is it possible that the damaged loom has damaged something in the domestic alternator?

 

Hopping that all of this makes some kind of sense!

 

TIA Keith.

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Alternator damage unlikely in my view. It sounds as if the shoreline is providing is lightly higher voltage than the alternator's regulator causing the alternator regulator to turn on and off. This will be more likely if you also have solar charging.

 

To test this theory next time it does it turn a hefty 12V load on (maybe a water pump and shower pump).If the flashing stops this is a likely explanation.

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Hi Tony,

 

Just been to try your theory and I am back to an issue before I discovered the burnt wiring which I did not mention before as I put it down to the burnt wiring. When switching on the key, the domestic warning light comes on momentarily and then goes off.

 

I am lost on this one, any ideas?

 

Really appreciate your comments.

 

Keith.

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11 minutes ago, kalees said:

Hi Tony,

 

Just been to try your theory and I am back to an issue before I discovered the burnt wiring which I did not mention before as I put it down to the burnt wiring. When switching on the key, the domestic warning light comes on momentarily and then goes off.

 

I am lost on this one, any ideas?

 

Really appreciate your comments.

 

Keith.

 

No, not without a decent wiring diagram for your specific engine. Also, the Beta alternator controller you mention complicates things.

 

The warning lamp should come on and stay on until the alternator starts to charge whatever the W/L circuit does. I think, but don't know, that Beta alternators tend to be nine diode machines and I also know some marinisers take a shortcut and feed the domestic alternator D+ (w/l) terminal from the ignitions switch rather than via a relay. If yours uses a relay to energize the domestic D+ then it might be a faulty relay.

 

If the alternator is like the Mitsubishi ones where internal electronics turn the warning lamp off then it might be an alternator fault. Such alternators tend not to have a D+ terminal but do have a feed from the ignition switch (Ign) and another for the warning lamp (WL).

 

I can't see enough of the burned wiring or see it clear enough to work out what happened, but it all seems to be on thin wiring and that suggests at least one cable shorted to something metal. Once one cable shorts and burns often the adjacent ones also suffer burning or heat damage. The question is what thin cable on an alternator connects to the battery so enough current to burn the cable can flow. It should not be D+ or warning lamp cable but could be the Ign one IF your alternator uses one. However, that is normally fed via an ignition switch so the fuse (if you have one) supplying the ignition switch should have blown.

 

A D+ might also burn with current from the field diodes but only after the alternator has energized and in this case the warning lamp should stay on. If that has happened filed diode may have failed but in that case I don't know why the warning lamp flashes.

 

Looking at the photo  it seems the blade connector on the brownish wire has the male portion displaced and twisted through 90 degrees. It also looks as if that connector may have been the source of the short. My suspect would be it fouled the moving part of the throttle cable. Inspecting the moving part should show a burn mark it that is what caused it. The question is what is that brownish wire for.

 

 

 

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If the cable I refer to as brownish is actually the red one from B+ and it did rub on the throttle cable it could easily do all that wiring damage, but it should not have damaged the alternator and probably not the controller.

 

It is a nine diode alternator.

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Further test now we know it is a none diode alternator.

 

Put a voltmeter (20V DC) between B+ and D+ on the alternator  terminals with wires still in position. Start and rev engine. In theory the meter should read zero but may read a few fractions of a volt. If more than about 0.5V then a field diode has failed.

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1 hour ago, Tony Brooks said:

Further test now we know it is a none diode alternator.

 

Put a voltmeter (20V DC) between B+ and D+ on the alternator  terminals with wires still in position. Start and rev engine. In theory the meter should read zero but may read a few fractions of a volt. If more than about 0.5V then a field diode has failed.

OOOps Tony, NINE diode, finger trouble.

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15 minutes ago, Tracy D'arth said:

OOOps Tony, NINE diode, finger trouble.

 

Yes, but more like blurry eye trouble for a while after I get up. Just another benefit of old age!

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Hi all

Just carried out the test and am getting 1.6 volts, just a note that there are no wires on the D+

 

All was good this morning but during this test domestic ignition light comes on and then goes straight off as soon as I turn the ignition on and just noticed that the volts on the battery monitor are only going up by about .5 but amps are charging at around 10 as we have been unplugged for a while.

 

Keith.

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If there are no wires on D+ then the Beta controller is also, in some way, controlling the warning lamp, as the diagram shows. I don't know enough about the Beta controller to help much more, but I do know they discontinued them for some reason

 

That 1.6 V suggests either a main pos. diode has failed or a field diode. Maybe get the alternator tested.

 

If it is a main diode related to the W terminal (phase tap) that may well be upsetting the controller because it seems to be using the W (rev counter) output to see if the engine is running or to measure the phase tap voltage, why I have no idea.

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Hi all,

 

The system seems all over the place, ok one minute and issues the next. I will take you advice Tony and have the alternator tested to see what that shows up.

 

Many thanks for all of your help.

 

Regards Keith 

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20 minutes ago, kalees said:

Hi all,

 

The system seems all over the place, ok one minute and issues the next. I will take you advice Tony and have the alternator tested to see what that shows up.

 

Many thanks for all of your help.

 

Regards Keith 

 

The majority of external alternator controllers retain the alternator's own regulator and in effect short it out when the controller thinks a higher voltage is needed. On these you can just unplug one wire between controller and alternator and take the controller totally out of circuit, but  the Beta one seems to discard the alternator's own regulator and replace it with just a brush box. This means that it is not possible to take the controller out of circuit, so you can decide if the problem is the controller or the alternator unless you fit the alternator voltage regulator cum brush box and then rewire the warning lamp direct to D+.  I think that it may not be simple for you to source the regulator so all you can do is get the alternator tested but make sure they know that it has no voltage regulator of its own. They will probably have to fit a regulator to test it, so if it tests OK, which means the controller is the most likely suspect, it might be best to ensure it is a 14.5 to 14.6V regulator, wire the W/L between the ignition switch aux terminal and D+ and see how it goes. You can always fit a different controller at a later date if find you need one. Personally I would fit some solar instead.

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Hi Tony,

 

Again, appreciate your advise. I feel that I might just revert to a straight forward replacement alternator and discard the controller, which I believe is now the Beta way, and was already looking into solar given the cost of diesel and the increase in engine hours and servicing costs.

 

Regards Keith.

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2 hours ago, kalees said:

Hi Tony,

 

Again, appreciate your advise. I feel that I might just revert to a straight forward replacement alternator and discard the controller, which I believe is now the Beta way, and was already looking into solar given the cost of diesel and the increase in engine hours and servicing costs.

 

Regards Keith.

 

I think that you are probably right, the least hassle and once done pretty much a standard setup.

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  • 2 weeks later...

All,

 

Just a quick update on this one, new 95 amp alternator fitted with standard regulator fitted. Now run for 3 days and all appears to be fine and back to normal.

 

Again, many thanks for all of the comments,

 

Keith.

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23 hours ago, kalees said:

Now run for 3 days and all appears to be fine and back to normal.

Thank you for the update - you'd be amazed how many seek advice and then vanish leaving no one the wiser whether the advice was good or not (or even taken or not)

 

Safe Cruising

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