Alternator issues

[Nick1969]

Hi. 

both the leisure battery and starter on my boat haven't been charging. I have checked with the multi meter, the leisure is 10.18 the starter is 11.69/ this reading states the same weather the engine is running at fast speed or tickoverr or not running at all ( whilst moored). I am thinking the alternater is finished and I need to replace it,however I can't help thinking that if I take the boat out and put the engine under pressure this may cick the alternate into action. Does it matter if the engine is under load to make the alternater to work /surely its just rpm that matters.

I have a lister SR2 . if i do need to replace what type would be best a type that works on low rpm

regards nick

 

[WotEver]

Does the red ignition warning light illuminate before you start the engine?

[rusty69]

It won't matter if its under load or not, but may require more than tick over revs

I am surprised you managed to start the engine at all with such low voltages. 

Can you check the output from the alternator itself? 

It may just be a loose connection /wiring fault/faulty regulator. 

Also check the obvious, belt OK. 

Edited April 20, 2017 by rusty69

[Nick1969]

I dont have any warning lights just the basics, and the revs I have had at tickover and full pelt , i have tested at the alternate itself  which is the same as the starter 11.69.

So if it doesn't matter weather itst under load or not it would appear to be finished.

When it was working, it would charge at about 14 , I thought this was good , perhaps it wasn't good and maybe that is why it is broken.

What should I replace it with, something I can buy of the shelf at autoparts.

Thanx for replys

nick

[WotEver]

15 minutes ago, Nick1969 said:

I dont have any warning lights just the basics

So how is the alternator excited?

This is the first thing I'd check.

If not via a warning light is there a resistor feeding it? Is it open circuit? Are the connections good?

17 minutes ago, Nick1969 said:

What should I replace it with

Without knowing what you have at present all we can say is 'something similar'. Any chance of a photo?

Of course, at this stage we don't know if it's faulty or not. 

[Nick1969]

I am not down the boat at the moment but if my memory is correct the alternater supply feed is from the ignition which in turn is connected to starter battery so its only engaged whilst the key is turned. Im going back down tommorow so will check all connections.

thanx for replying 

[Mikexx]

6 hours ago, Nick1969 said:

I am not down the boat at the moment but if my memory is correct the alternater supply feed is from the ignition which in turn is connected to starter battery so its only engaged whilst the key is turned. Im going back down tommorow so will check all connections.

thanx for replying 

 

Generally, the switched 12V via the ignition switch goes to a small bulb, and the other of the bulb goes to the alternator. If there is no bulb, or an equivalent load, then the alternator will not excite and you'll get no output.

If you can get at this terminal on the alternator, it would be useful to know the voltage you get here with ignition turned on.

 

[RD1]

I agree with the previous post, if the ignition light bulb has gone open circuit, and you can't get to it, you need a length of wire croc clip on one end, say  a 12 volt 5 watt bulb( car side light bulb) in series, with insuluated terminals, with the remainder of the wire with a croc clip on that end.

So one croc clip on a 12 volt live, say engine starter positive, then hunt out the alternator and place the croc clip on the thinner terminal, the exciter coil connection, on the alternator, make sure the wire cannot snag on the drive belt, then go through a start process, initially the bulb will light, then should go out when the engine runs and if this is the cause, then  you should have power.

It's amazing what you can fault find with a 12 volt bulb and a bit of wire, fuse checking, continuity.

Good luck,

Richard

Edited to say , I think this trip you need to be organising a way to get those batteries charged, if at home you may need to take a trolley, or find electric shore power. The batteries if left will soon become unserviceable, and they may have lost some capacity already.

 

Edited April 21, 2017 by RD1
Extra advice added.

[Sea Dog]

8 minutes ago, RD1 said:

It's amazing what you can fault find with a 12 volt bulb and a bit of wire, fuse checking, continuity.

... If you know what you're doing.

[Neil Smith]

Take the alternator to a local repair shop that can be found on Google and get it tested, they might only have to replace the regulator but if it is shot at least they can mat h it up with a recon.

Neil

[Nick1969]

Thanx for all the replys, I've been thinking about this since last night, I was even wundering weather it has ever worked and the wiring had been wrong from day 1 .

10 hours ago, Mikexx said:

 

Generally, the switched 12V via the ignition switch goes to a small bulb, and the other of the bulb goes to the alternator. If there is no bulb, or an equivalent load, then the alternator will not excite and you'll get no output.

If you can get at this terminal on the alternator, it would be useful to know the voltage you get here with ignition turned on.

 

Im pretty sure this is what i have apart from the bulb. I have just the cable from the 12 v ignition to the alternater, this would work wouldn't it.

 

2 hours ago, RD1 said:

I agree with the previous post, if the ignition light bulb has gone open circuit, and you can't get to it, you need a length of wire croc clip on one end, say  a 12 volt 5 watt bulb( car side light bulb) in series, with insuluated terminals, with the remainder of the wire with a croc clip on that end.

So one croc clip on a 12 volt live, say engine starter positive, then hunt out the alternator and place the croc clip on the thinner terminal, the exciter coil connection, on the alternator, make sure the wire cannot snag on the drive belt, then go through a start process, initially the bulb will light, then should go out when the engine runs and if this is the cause, then  you should have power.

It's amazing what you can fault find with a 12 volt bulb and a bit of wire, fuse checking, continuity.

Good luck,

Richard

Edited to say , I think this trip you need to be organising a way to get those batteries charged, if at home you may need to take a trolley, or find electric shore power. The batteries if left will soon become unserviceable, and they may have lost some capacity already.

 

Im of down boat in a mo and will retrieve battery to charge them, I think my wiring is right but to be honest I just don't know, Iwill run through your advice richard once batterys are charged

thanx all

[rusty69]

1 minute ago, Nick1969 said:

10 hours ago, Mikexx said:

 

Im pretty sure this is what i have apart from the bulb. I have just the cable from the 12 v ignition to the alternater, this would work wouldn't it.

No. I think you need a bulb or resistor to excite the alternator. 

[bizzard]

2 minutes ago, rusty69 said:

No. I think you need a bulb or resistor to excite the alternator. 

Especially if the SR2 has the small diameter alternator drive pulley on the camshaft, instead of the large diameter marine one.

[rusty69]

A bit about alternators from Tony Brooks excellent site:-

 

 

http://www.tb-training.co.uk/MarineE08.html#CHARGING SYSTEM – ALTERNATOR

[WotEver]

1 hour ago, Nick1969 said:

I was even wundering weather it has ever worked and the wiring had been wrong from day 1

It's possible that the wiring has always been wrong I guess but it's also likely that the bulb has been blown for some time and that's why you don't realise that you have one. Or, as I said earlier, someone has wired in a resistor instead of a bulb and it's burnt out. Or, a wire has come adrift. 

[Sir Nibble]

Firstly, there are alternators that work without a warning light and have no provision for one. Testing with the assumption that the alternator is the familiar six diode type may cause damage should that assumption prove wrong. Connecting the D+ to ignition is something sometimes done to achieve the lowest possible cut in speed but must be done via a diode.

A picture of the alternator would allow us to know precisely what we are dealing with.

[WotEver]

21 hours ago, WotEver said:

Any chance of a photo?

 

7 minutes ago, Sir Nibble said:

A picture of the alternator would allow us to know precisely what we are dealing with.

 

[Sir Nibble]

Without it everything is a guess.

[Mikexx]

11 hours ago, Nick1969 said:

Im pretty sure this is what i have apart from the bulb. I have just the cable from the 12 v ignition to the alternater, this would work wouldn't it.

It should work the same as if there was bulb in series, in fact there the alternator will kick in earlier and there should be no need to raise revs for the alternator to produce an output as per most other installations.

A direct connect (without a bulb) is not normally done, as you lose a warning light. A consequence is the position you're in, where you can't confirm if there is any excitation to the alternator or that it simply that doesn't produce an output.

You need to check if you see 12V at the relevant point on the alternator as described earlier. There may be more than one 'small' terminal. I have a second for the rev counter.

Which leads me to my next question: if you have a rev counter, how is it driven?

[Mikexx]

10 hours ago, WotEver said:

It's possible that the wiring has always been wrong I guess but it's also likely that the bulb has been blown for some time and that's why you don't realise that you have one. Or, as I said earlier, someone has wired in a resistor instead of a bulb and it's burnt out. Or, a wire has come adrift. 

The wiring up of an alternator is remarkably simple. Just two wires need to be connected (ignoring any rev counter connection). One fat wire to the battery, and a smaller second wire to the ignition switch (usually) via a bulb.

A wire coming adrift is quite likely.

[WotEver]

WE NEED A PHOTO of the alternator! 

Edited April 21, 2017 by WotEver
Typo

[Sir Nibble]

*Sigh*

If the D+ is connected to ignition without a lamp or diode in place then the little field diodes  are trying to charge the battery and they don't like it. I recall once a thread where the warning light was getting bigger and bigger as attempts were made to get the alternator to cut in at a sensible speed, it was on the way to blowing the warning light switching circuit which everyone assumed wasn't there blithely continuing to work on the basis that all alternators are the same. A single picture and  we  can give rock solid advice with confidence, without it anyone who knows alternators will be working on crossed fingers and hope and anyone who doesn't recognise the possibilities of damage doesn't know alternators.

[Mikexx]

3 hours ago, Sir Nibble said:

*Sigh*

If the D+ is connected to ignition without a lamp or diode in place then the little field diodes  are trying to charge the battery and they don't like it. I recall once a thread where the warning light was getting bigger and bigger as attempts were made to get the alternator to cut in at a sensible speed, it was on the way to blowing the warning light switching circuit which everyone assumed wasn't there blithely continuing to work on the basis that all alternators are the same. A single picture and  we  can give rock solid advice with confidence, without it anyone who knows alternators will be working on crossed fingers and hope and anyone who doesn't recognise the possibilities of damage doesn't know alternators.

I confess to assuming that the charging circuit would be intact, and the low cuurent field diodes coupled with long lenghts of weedy wire would be such little or no current would pass through the field diodes into the battery and associated loads. Obviously in the case of a fault this might no longer be the case. I have seen a poor connection at a crimp connector in the charging circuit that would cause the problem you have raised.

A very good point.

[Nick1969]

Many thanx for all reply,

I truly appreciate all help given.

I have .......1) charged battery

                  2) connected light between ignition and alternater.

                  3) drawn engine room wiring diagram.

                  4) taken photos of alternate.

I have started engine and the light has remained on, at high and low revs.

 Ive checked all wiring and connectors

can i just say that what appears to be a black cable on the alternate is the thicker red cable going to the battery live.

Many thanx

nick

p.s im off to the boat in a minut e and will get a measurement for pully on cam shaft

regards

 

[Mikexx]

It looks wired up fine. The W is for a rev counter and connection is optional.

Does the bulb flicker in any way?

I am assuming the alternator earth is through the starter motor earth, and in any case the fact the bulb has lit implies the earth connection is made.

What is the voltage on the smaller stud, ie to the bulb (wrt earth)? It might sound silly but you can confirm your wiring by removing the wire and see the bulb go out.

With a steady lit bulb, my instinct says its the regulator, but I feel the alternator needs to come out and the diode pack(s) checked. As Sir Nibble intimated the field diodes could well be damaged.

The issue for me would be I can buy a 70amp Lucas A127 alternator on eBay for £50 and how much more effort do you want to put into this? Yours is a different part number though:

  http://www.ebay.co.uk/itm/Ford-Escort-Fiesta-Courier-Orion-Granada-New-Alternator-75A-3-Ribs-60mm-Pulley-/311758712572

might be the one? These are Chinese lookalikes but what the hell at that price!