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Battery doesn't seem to be charging


hackenbush

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The common reason a new regulator brings A127s back to life is that the brushes that come as part of the the regulator have worn out. We can not say for certain that the problem is not the regulator but as its a solid state device and the alternator is far from old I would suggest its less likely in this case. If I am right about the fan rotation then overheating might have damaged the regulator but I would suspect the field diodes would be a more likely candidate.

I would say it would be better to get the thing stripped and tested by someone who knows what they are about rather than paying for and changing parts "in case".

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The fan on the A127 is correct for normal clockwise rotation, that is looking at the pulley face on. Which would usually be correct for a marine SR3, but check by jabbing the starter to make sure of the rotation as an ex industrial SR3 could rotate anti-clockwise.  The fan on the old ACR I cannot see properly but it looks as if it might be bi-directional, could even be a plastic one with integral pulley. These were in common use on many cars in the 1970-80's.

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9 hours ago, Tony Brooks said:

The first alternator (the all metal one) is a Lucas A127 clone. The old one with the big plastic end cover is a late version of a Lucas ACR. They should be direct swaps EXCEPT the A127 has a nut & stud main terminal while the ACR uses a PAIR of 9mm blades. It is just possible but very unlikely that the second large blade is for battery sensing but I have only seen them on a few MOD applications. If you do swap I would  advise, bodge that it is, that you strip back and split the the main red cable enough to fit 2 x 9mm blades on the end and insulate the lengths of bare conductors. This is because in vehicle use one blade fed the battery while the other fed the car's electrical loads so the full output never went through just one blade.

Before you condemn the newest alternator do just one  extra test. Undo the nut holding the small/thin wire onto the stud but leave the terminal on the stud for now. Turn on the ignition. The warning lamp should illuminate. Now, with with the ignition still on, pull the terminal off the stud. The lamp should go out. If it does then the alternator is suspect. If it stays on there is a short to negative on the cable between warning lamp and alternator - this will prevent the machine energising.

On the back mounting bracket of both alternators you will have a sliding bush that might prevent the ACR fitting your mounting points. Although the bushes will slide they can be very stiff so if you need to move one to get it to fit support the bracket (I use a socket) and gently tap the bush back through the bracket a little. Those brackets snap too easily to just whack the bush without support. The bush shoudl just pull through with the bolt once the alternator is mounted.

I think the problem machine may well have the wrong handed fan on it ( Lister alternators being cam shaft driven tend to turn in the opposite direction to "normal"). BIZ or someone will confirm. If I am correct you MUST get the correct fan or a bi-directional fan to prevent you burning out any new alternator. This also applied to the ACR unless it has the correct fan on it.

OK, I've had a bit of time to study your post more closely and have a few questions. I'm not near the boat right now so am a bit blind but just want to clarify by basically repeating back to you in ultra-simpleton.

in regards to the red cable attaching are you saying that at the moment it is one wire attached to nut and stud and needs to be adapted for blade and must be attached to both blades not just one?

in regards to final test if indeed there is a short to negative on the cable what would be my next step?

Would you mind describing what the "sliding bush" looks like? I just can't picture it. Is this the black plastic cover? Obviously the one on the installed alternator is now allowing it to mount. I'm having a hard time picturing the procedure.

 

As for the fan. Is there any way to tell whether I have the wrong fan? Is it a pretty obvious procedure to swap out the fan?

 

thank you for all your help

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9 hours ago, Neil Smith said:

After testing as Tony suggests and it is the alternator then it might be worth putting in a new regulator, they are cheap and it looks like you have room to do it in situ, just done it on my motor home that had your problem and it's fine now charging at 14.2 volts.

Neil

is there a chance that the whole problem could be a faulty regulator?

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7 hours ago, Tony Brooks said:

The common reason a new regulator brings A127s back to life is that the brushes that come as part of the the regulator have worn out. We can not say for certain that the problem is not the regulator but as its a solid state device and the alternator is far from old I would suggest its less likely in this case. If I am right about the fan rotation then overheating might have damaged the regulator but I would suspect the field diodes would be a more likely candidate.

I would say it would be better to get the thing stripped and tested by someone who knows what they are about rather than paying for and changing parts "in case".

 

6 hours ago, bizzard said:

The fan on the A127 is correct for normal clockwise rotation, that is looking at the pulley face on. Which would usually be correct for a marine SR3, but check by jabbing the starter to make sure of the rotation as an ex industrial SR3 could rotate anti-clockwise.  The fan on the old ACR I cannot see properly but it looks as if it might be bi-directional, could even be a plastic one with integral pulley. These were in common use on many cars in the 1970-80's.

Could you rephrase "jabbing the starter" just so I'm clear? 

Is there a way I can test the regulator? Is it by sight? Would the same be true of the fan direction?

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Just now, hackenbush said:

OK, I've had a bit of time to study your post more closely and have a few questions. I'm not near the boat right now so am a bit blind but just want to clarify by basically repeating back to you in ultra-simpleton.

in regards to the red cable attaching are you saying that at the moment it is one wire attached to nut and stud and needs to be adapted for blade and must be attached to both blades not just one?

in regards to final test if indeed there is a short to negative on the cable what would be my next step?

Would you mind describing what the "sliding bush" looks like? I just can't picture it. Is this the black plastic cover? Obviously the one on the installed alternator is now allowing it to mount. I'm having a hard time picturing the procedure.

 

As for the fan. Is there any way to tell whether I have the wrong fan? Is it a pretty obvious procedure to swap out the fan?

 

thank you for all your help

 

Red cable question - Yes the thick red cable will need to be adapted to fit a 9mm blade. You can use just one blade but for the reason I explained I would use both.

Short to negative question - find out where the short is and rectify it. It may be easier to run a new length of cable from warning lamp to the small terminal on the alternator.

You can see the bush as a "bit of tube" stuck through the back mounting bracket in one of your photos of the ACR that is not fitted. Place a socket with an opening slightly larger than the bush OD on the bench, ground or deck. Hold alternator, pulley end upwards and place the back bracket on the socket so the socket supports the back of the end bracket. Tap the bush down through the end bracket and part way into the socket until you can get the alternator onto the mounts.

Fan Question - it all depends upon which way your alternator is rotated by the engine - read Bizzards post or tell the forum. It may or may not be correct. Bizzard says that if it is a true marine version of the engine the fan is probably correct but if its a converted industrial unit it may not be. I also suspect if it was ever in a twin engined boat it may not be.

Just now, hackenbush said:

is there a chance that the whole problem could be a faulty regulator?

I am getting a bit annoyed now - what bit of " We can not say for certain that the problem is not the regulator but as its a solid state device and the alternator is far from old I would suggest its less likely in this case. " do you not understand?

By all means go and spend anything between about £5 and £25 plus P&P on a new regulator, make sure you know the knack of extracting the brush part without snapping a brush, fit it and try it. Then come back and tell us if it worked. Oh, and by the way, although this is less likely to apply to your alternator, the do it again in a few months time because the brushes have worn right through a slip ring that you did not know shoudl have been checked (very hard to do in situ!).

I am not going to give you a definitive answer to a question for which there is no such answer - it would just be a guess. I have tried to guide you but that is all i cam do.

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Just now, hackenbush said:

 

Could you rephrase "jabbing the starter" just so I'm clear? 

Is there a way I can test the regulator? Is it by sight? Would the same be true of the fan direction?

Bizzard wants you to operate the starter to see which way the alternator turns. The re-read what he says. If the alternator runs clockwise when looking directly at the FRONT (that is looking backwards) of the engine then the fan is correct. If the engine goes the other way it is not.

Nicknorman and other electronics experts may be able to test the regulator if they have the internal circuit diagram and can get into it. I know of no other way apart from substitution.

 

 

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Just now, hackenbush said:

 

Could you rephrase "jabbing the starter" just so I'm clear? 

Is there a way I can test the regulator? Is it by sight? Would the same be true of the fan direction?

Jabbing the starter means just momentarily pressing the starter button or turning the starter key to move the engine a bit in its natural direction of rotation whilst watching the alternator pulley to see which way it turns, you can can of course start the engine up. But the best way is to pull the engine stop out so that it won't start whilst pressing the starter button and watching the pulley. Its almost certain that you have a normal clockwise direction alternator drive.  A better clearer photo of the ACR alternator would help with determining the type of fan ''Probably bi-directional. The pulleys and fans would not be interchangeable between the two.  The two big + spade terminals on the ACR alternator are actually joined together so it doesn't matter which the fat red +cable goes onto. The thinner warning light wire simply goes to one terminal on the warning light holder and the other terminal on it is connected to the live ON terminal on the ignition switch or via a split charge relay if you have one.

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Just now, mross said:

Hackenbush - you are asking good questions.  Your feedback ensures an ongoing response from very experienced electrical experts.  Thanks for giving good answeres too.

Sorry but I am going to disagree with that. I took time to explain  why I suspected a change  would not solve his problem and told him we could not be certain about the regulator. Rather than read or say he did not understand he came back to try to get me to say the regulator is/is not OK - TWICE. He seemed to ignore my advice that it may be better to get the whole alternator tested.

It was fine up to that point but at the moment I do not feel inclined to offer any more help.,

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Just now, Tony Brooks said:

 

Red cable question - Yes the thick red cable will need to be adapted to fit a 9mm blade. You can use just one blade but for the reason I explained I would use both.

Short to negative question - find out where the short is and rectify it. It may be easier to run a new length of cable from warning lamp to the small terminal on the alternator.

You can see the bush as a "bit of tube" stuck through the back mounting bracket in one of your photos of the ACR that is not fitted. Place a socket with an opening slightly larger than the bush OD on the bench, ground or deck. Hold alternator, pulley end upwards and place the back bracket on the socket so the socket supports the back of the end bracket. Tap the bush down through the end bracket and part way into the socket until you can get the alternator onto the mounts.

Fan Question - it all depends upon which way your alternator is rotated by the engine - read Bizzards post or tell the forum. It may or may not be correct. Bizzard says that if it is a true marine version of the engine the fan is probably correct but if its a converted industrial unit it may not be. I also suspect if it was ever in a twin engined boat it may not be.

I am getting a bit annoyed now - what bit of " We can not say for certain that the problem is not the regulator but as its a solid state device and the alternator is far from old I would suggest its less likely in this case. " do you not understand?

By all means go and spend anything between about £5 and £25 plus P&P on a new regulator, make sure you know the knack of extracting the brush part without snapping a brush, fit it and try it. Then come back and tell us if it worked. Oh, and by the way, although this is less likely to apply to your alternator, the do it again in a few months time because the brushes have worn right through a slip ring that you did not know shoudl have been checked (very hard to do in situ!).

I am not going to give you a definitive answer to a question for which there is no such answer - it would just be a guess. I have tried to guide you but that is all i cam do.

Thank you Tony for the clarifications, very useful.

Just so you know, I responded to with the question about the regulator before I had reached your post mentioning the regulator.

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The ACR alternator will have a maximum output of around 45amps, possibly 35amp, whereas the A127 is around 70amps, but you won't notice much difference in charging power unless you have a huge battery bank, which I doubt you have, you probably have two domestic batteries and one starter battery ?

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I shut down last night immediately after my last post in case I upset the OP and have only just been able to get back on.

May I suggest that asking more questions before reading all the posts is not such a good idea because some questions might have been answered.

If the alternators are swapped over I am almost certain that the terminal on the thin red lead (warning lamp wire) will also have to be changed for a 6mm female blade. The warning lamp terminal on the old ACR will be a male 6mm blade close by and in line with the two male 9mm blades.

For completeness although I suspect the markings may not be on the ACR in general the main positive output terminal for a thick cable is often marked B+, if the alternator does not use the case as the negative connection a further stud will be markjed B-. The warning lamp terminal is often D+.

 

 

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1 hour ago, Tony Brooks said:

I shut down last night immediately after my last post in case I upset the OP and have only just been able to get back on.

May I suggest that asking more questions before reading all the posts is not such a good idea because some questions might have been answered.

If the alternators are swapped over I am almost certain that the terminal on the thin red lead (warning lamp wire) will also have to be changed for a 6mm female blade. The warning lamp terminal on the old ACR will be a male 6mm blade close by and in line with the two male 9mm blades.

For completeness although I suspect the markings may not be on the ACR in general the main positive output terminal for a thick cable is often marked B+, if the alternator does not use the case as the negative connection a further stud will be markjed B-. The warning lamp terminal is often D+.

 

 

Been at work and then sleep. Am now about to work methodically through the advice. And yes, should certainly read the whole thread before responding. I'm on a phone with a small screen and things work differently at this size!

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Started with Tony's advice:

"Before you condemn the newest alternator do just one  extra test. Undo the nut holding the small/thin wire onto the stud but leave the terminal on the stud for now. Turn on the ignition. The warning lamp should illuminate. Now, with with the ignition still on, pull the terminal off the stud. The lamp should go out. If it does then the alternator is suspect. If it stays on there is a short to negative on the cable between warning lamp and alternator - this will prevent the machine energising."

pic below is of the thin cable I've disconnected just to make sure it's the correct one. The ID marking is hidden from view

warning light stays illuminated

 

image.jpg

Edited by hackenbush
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13 minutes ago, hackenbush said:

Started with Tony's advice:

"Before you condemn the newest alternator do just one  extra test. Undo the nut holding the small/thin wire onto the stud but leave the terminal on the stud for now. Turn on the ignition. The warning lamp should illuminate. Now, with with the ignition still on, pull the terminal off the stud. The lamp should go out. If it does then the alternator is suspect. If it stays on there is a short to negative on the cable between warning lamp and alternator - this will prevent the machine energising."

pic below is of the thin cable I've disconnected just to make sure it's the correct one.

warning light stays illuminated

 

image.jpg

If that terminal you took off is touching that alternator bracket the light will stay on. Pull it away and see if the light goes out.

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That's the correct cable and the lamp should have gone out. Note Bizzards advice.

Next test if you have a voltmeter. Leave the warning lamp wire disconnected ( and the terminal not touching metal).

Put the voltmeter across the batteries as discussed before. Get a short length of cable with both ends trimmed back a mm or two. Start the engine and rev at about 100o to 1500 rpm or more. Use the short length of wire to touch the little terminal on the alternator and the large one with the thick red wire on it. Hopefully the voltmeter will jump up showing the alternator is charging. Even if it does not the warning lamp circuit needs sorting.

Follow the whole length of that thin red wire and any other wire connected to it back to the warning lamp. You are looking for that  wire trapped under metal or resting against metal so the insulation is chaffed through. Once you are sure there is no short you can think about replacing the wire run but to be sure nothing odd is going on with the warning lamp itself with the ignition on disconnect the   cable (probably thin red) on the alternator side of the warning lamp. The lamp should go out. If it does not I think we need photos of the top and underside of the instrument panel in case what you think is the charge warning lamp is not. It could be an oil pressure warning lamp or on some Lister and overheat warning lamp. It may even be a lamp that is wired to tell you the ignition is switched on but if it is its odd because the charge warning lamp should do that.

 

 

 

.

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7 minutes ago, Tony Brooks said:

That's the correct cable and the lamp should have gone out. Note Bizzards advice.

Next test if you have a voltmeter. Leave the warning lamp wire disconnected ( and the terminal not touching metal).

Put the voltmeter across the batteries as discussed before. Get a short length of cable with both ends trimmed back a mm or two. Start the engine and rev at about 100o to 1500 rpm or more. Use the short length of wire to touch the little terminal on the alternator and the large one with the thick red wire on it. Hopefully the voltmeter will jump up showing the alternator is charging. Even if it does not the warning lamp circuit needs sorting.

Follow the whole length of that thin red wire and any other wire connected to it back to the warning lamp. You are looking for that  wire trapped under metal or resting against metal so the insulation is chaffed through. Once you are sure there is no short you can think about replacing the wire run but to be sure nothing odd is going on with the warning lamp itself with the ignition on disconnect the   cable (probably thin red) on the alternator side of the warning lamp. The lamp should go out. If it does not I think we need photos of the top and underside of the instrument panel in case what you think is the charge warning lamp is not. It could be an oil pressure warning lamp or on some Lister and overheat warning lamp. It may even be a lamp that is wired to tell you the ignition is switched on but if it is its odd because the charge warning lamp should do that.

 

 

 

.

Does thickness of the testing wire matter?

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12 minutes ago, hackenbush said:

It was totally clear of anything when I started ignition and light remained on

OK - try the test with the short length of wire, you will be in effect doing the same job as the warning lamp in exciting the alternator. You would find it very difficult to do any damage with this test.

 

If you do not have a voltmeter then start checking the cables between alternator/engine and the instrument panel for chaffing and pinching.

 

 

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2 minutes ago, hackenbush said:

Does thickness of the testing wire matter?

No, within reason but thin is easier to bend in a U so it can touch the two terminals. I know many that would use a  screwdriver but that is too easy for causing short circuits.

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