Lucas A127

[blackrose]

I've completely removed my old Sterling alternator regulator but the 70A Lucas A127 alternator is still putting out 14.62v, as measured at the new sealed lead acid battery terminals. That seems a bit high to me. My understanding is that the internal regulator on an A127 should limit voltage to 14.2v or a very maximum of 14.4v.

 

The new battery was already at 12.7v when it was delivered, so pretty well charged and once I saw the high voltage from the alternator I switched off the engine so it was only charged for 10 or 15 mins.

 

After blowing a battery up previously and spending days clearing up the mess I'm really conscious that I don't want to do that again.

 

If the A127 regulator has failed I can replace it, but it's made me wonder if I should have left the Sterling regulator in place on the basis that if the internal regulator failed it would prevent a high voltage getting to the battery?

 

So I'm wondering what to do now? Buy/fit a new A127 regulator. Re-fit the old Sterling battery boiler?

[Tony Brooks]

Personally, I would give the batteries a good discharge and watch the voltage as they charge up. I have noticed on my Paris-Rhone alternator and a very few others that they can produce a higher than nominal maximum battery voltage when faced with very well charged batteries. 

 

What is the maximum charging voltage the battery manufacturer recommends? One major battery vendor was telling customers they needed a higher charging voltage than most alternators could produce, and also I think that voltage would be fine for open cell lead acid batteries as long as you keep them topped up, and it only occurs with well charged batteries.

 

 Remember that a blown field diode on a nine diode machine can cause the charging voltage to go high, as can a dry joint on those diodes.

 

Unless the Sterling wiring isolates the alternator's own regulator then if the regulated voltage was higher than the Sterling regulated voltage then the A127 regulator will take control, so check that it would totally isolate the A127 regulator before you reconnect it.

 

The A127 regulator is not expensive, so diagnosis by substitution may be a viable tactic, but I would have the alternator apart and check the field diodes and soldering as well.

 

 

[GUMPY]

I would fit a new regulator.

Cargo used to make 14.2v and 14.6v regulators not sure if they still do.

[nicknorman]

The Sterling reg can only increase charging voltage, it can’t decrease the voltage below whatever the alternator’s internal regulator sets.

[blackrose]

15 minutes ago, Tony Brooks said:

Personally, I would give the batteries a good discharge and watch the voltage as they charge up. I have noticed on my Paris-Rhone alternator and a very few others that they can produce a higher than nominal maximum battery voltage when faced with very well charged batteries. 

 

What is the maximum charging voltage the battery manufacturer recommends? One major battery vendor was telling customers they needed a higher charging voltage than most alternators could produce, and also I think that voltage would be fine for open cell lead acid batteries as long as you keep them topped up, and it only occurs with well charged batteries.

 

 Remember that a blown field diode on a nine diode machine can cause the charging voltage to go high, as can a dry joint on those diodes.

 

Unless the Sterling wiring isolates the alternator's own regulator then if the regulated voltage was higher than the Sterling regulated voltage then the A127 regulator will take control, so check that it would totally isolate the A127 regulator before you reconnect it.

 

The A127 regulator is not expensive, so diagnosis by substitution may be a viable tactic, but I would have the alternator apart and check the field diodes and soldering as well.

 

 

 

Thanks Tony.

 

From experience with similar sealed LA Hancook batteries and communication with a supplier several years ago, they can safely go to 14.6v. I'm just being extremely cautious because if it was 14.6v shortly after start-up I was worried that it might climb higher. It could be as you say, that because they're well-charged they're going straight into "absorption". I wasn't able to measure current going into the battery but next time I will put a clamp meter over the cable from the alternator. Also as it's the buffer battery for my lithium bank I'm not able to discharge it.

 

I've taken a regulator out of an alternator before so I'm confident in replacing that, but I've never taken an alternator apart. I imagine springs and carbon brushes flying everywhere?

15 minutes ago, GUMPY said:

I would fit a new regulator.

Cargo used to make 14.2v and 14.6v regulators not sure if they still do.

 

Thanks, I'll have a look online.

 

8 minutes ago, nicknorman said:

The Sterling reg can only increase charging voltage, it can’t decrease the voltage below whatever the alternator’s internal regulator sets.

 

Ok thanks, so I was right to get rid of it. 👍

 

 

 

Would this one be ok? It doesn't specify max voltage. 

 

https://ebay.us/m/OMkqAC

Edited June 3 by blackrose

[Tony Brooks]

1 hour ago, blackrose said:

I've taken a regulator out of an alternator before so I'm confident in replacing that, but I've never taken an alternator apart. I imagine springs and carbon brushes flying everywhere?

Is any solar involved, if so, that means the battery is likely to be very well charged at this time of year. As long as you are not using the long wire method or a bidirectional B to B between the LA and Li then clipping a load (head lamp bulb) across the LA battery for half an hour will discharge it sufficiently to see if the voltage falls.

 

The brushes and springs come out with the regulator, and there are no other brushes and springs inside.

 

If you want to take it apart:-

 

Remove the regulator.

 

Remove all the nuts and washers from the terminal studs, taking care not to mix steel washers up with insulating ones and where they go

If fitted, pull the lead from the box like radio suppressor off its blade.

 

Witness mark the two cast end brcakets and the laminated stator so you can reassemble it correctly - DO NOT use a cetre punch on the stator.

 

Remove the three long screws holding the two cast end brcakets and stator together, and lift the back (connection end) brcaket off the stator. Do not take the drive end bracket off the stator unless it falls out.

 

Normally the field diodes are three electronic/capacitor like diodes soldered amoungst the main diodes and to the stator phase connections, but I am not sure if the stator connection will have to be unsldered to prevent meter current flowing "backwards" through the stator and giving a lowish resistance in both directions.  I am afraid it is try it and see unless someone with a less addled brain knows that answer.

 

I rather susepct that you will opt to try a new regulator and only worry about the field dodes if you still gte a high voltage.

 

 

 

Edited June 3 by Tony Brooks

[blackrose]

3 hours ago, Tony Brooks said:

 

I rather susepct that you will opt to try a new regulator and only worry about the field dodes if you still gte a high voltage.

 

 

Yes, I'll try a new regulator first and if it still produces a high voltage I'll follow the steps above and take the alternator apart. Thanks

 

I've just found a brand new regulator in my box of electrical bits. Must have been in there for nearly 20 years! I'll fit it now...

Edited June 3 by blackrose

[blackrose]

Just changed the regulator. I thought that had worked as it wasn't going above about 14v but as soon as I disabled charging on the Orion XS (as I'll need to do when my lithium batteries are getting full) the voltage on the buffer battery jumped up to 14.7v. It's that high at idling and slightly lower (14.6v) at 1000rpm.

 

Why on earth is a Lucas A127 with no boost system in place putting out 14.7v? 

 

I guess I'm taking the alternator apart next. 

 

I can't help thinking that's what blew my battery up last time. The transit bung didn't help.

 

Will I have damaged that sealed battery taking it up to 14.v for half a minute?

Edited June 3 by blackrose

[nicknorman]

No. 14.7v is not that high. But there might be a problem with a field diode. It might go higher under no load so best to sort it and even 14.7v for long periods is inadvisable. Voltage decreasing at higher revs might also pint to a field diode. I think.

Edited June 3 by nicknorman

[blackrose]

Is it worth me taking the alternator apart or just buy a new alternator?

 

Is it going to be easy to find the correct field diodes and how much will I spend on 3? Presumably they're cheap and readily available?

 

I think I can buy a 75A A127 for about 60 quid

[pearley]

15 minutes ago, blackrose said:

Is it worth me taking the alternator apart or just buy a new alternator?

 

Is it going to be easy to find the correct field diodes and how much will I spend on 3? Presumably they're cheap and readily available?

 

I think I can buy a 75A A127 for about 60 quid

Or a complete rectifier assembly for around £18. Although personally I would just fit a new/rebuilt alternator.

[Tony Brooks]

17 minutes ago, pearley said:

Or a complete rectifier assembly for around £18. Although personally I would just fit a new/rebuilt alternator.

 

and then put it on EBay. It may not give any high voltage into a standard LA set up. 

 

35 minutes ago, blackrose said:

Is it going to be easy to find the correct field diodes and how much will I spend on 3? Presumably they're cheap and readily available?

 

The test was more a question of ruling them out or not as a diagnosis step. If not then a new regulator/ alternator would have been the next step

[blackrose]

Ok thanks I'll just buy a new alternator. 

 

Any tips on finding one with the correct pulleys & mounting configuration?

Edited June 3 by blackrose

[Kingdom Isambard Brunel]

Right hand and left hand can be switched over by removing the 3 through bolts and rotating the front housing, maybe drilling out one bracket.

I always buy a universal one with the 3 hole tensioning mount, saves carrying more than one and it will fit any.

If you buy cheap you may have to reuse your fan and pulley.

[blackrose]

This is the alternator.

 

 

Edited June 3 by blackrose

[Kingdom Isambard Brunel]

3 minutes ago, blackrose said:

This is the alternator.

 

 

That is a universal  3 hole one, set up as left hand.

[blackrose]

Thanks 👍 

 

This one looks like mine. 

 

https://ebay.us/m/ZSzpYa

 

And there is this one on Amazon. 

 

https://amzn.eu/d/b9G7AWT

 

Which one looks better?

 

Edited June 3 by blackrose

[Wanderer Vagabond]

1 hour ago, blackrose said:

Ok thanks I'll just buy a new alternator. 

 

Any tips on finding one with the correct pulleys & mounting configuration?

Whereabouts are you in the Country? My 'go-to' place when I'm in Braunston is Electro-Start (https://electrostart.co.uk/) who have very reasonably priced alternators and regulators for sale. If you need to change the regulator, you will need a 5.5mm spanner to do so DAMHIK.

 

Interestingly, whilst on the topic of alternators, I've just changed mine (again) as the overvoltage warning light from the Adverc (along with ignition light) was coming on. Had another run today with the new alternator and after about 40 minutes of running at 1600 rpm, the bl**dy light came on again. As I'd previously changed the regulator on the alternator that was on the engine, and have now changed the alternator itself, I've come around to thinking that the Adverc is the thing that is at fault, so I've now disconnected that leaving the charging system relying on the regulator fitted to the alternator. Anyone got any views of anything else that could have been at fault?

[blackrose]

2 minutes ago, Wanderer Vagabond said:

Whereabouts are you in the Country? My 'go-to' place when I'm in Braunston is Electro-Start (https://electrostart.co.uk/) who have very reasonably priced alternators and regulators for sale. If you need to change the regulator, you will need a 5.5mm spanner to do so DAMHIK.

 

 

I'm between Wellingborough and Peterborough and I often go into Northampton so I can get to Braunston ok. Thanks

[Wanderer Vagabond]

2 minutes ago, blackrose said:

 

I'm between Wellingborough and Peterborough and I often go into Northampton so I can get to Braunston ok. Thanks

Just to clarify, Electrostart are on the industrial estate in Daventry, which for me is rideable from Braunston. 

[Tony Brooks]

30 minutes ago, Wanderer Vagabond said:

Whereabouts are you in the Country? My 'go-to' place when I'm in Braunston is Electro-Start (https://electrostart.co.uk/) who have very reasonably priced alternators and regulators for sale. If you need to change the regulator, you will need a 5.5mm spanner to do so DAMHIK.

 

Interestingly, whilst on the topic of alternators, I've just changed mine (again) as the overvoltage warning light from the Adverc (along with ignition light) was coming on. Had another run today with the new alternator and after about 40 minutes of running at 1600 rpm, the bl**dy light came on again. As I'd previously changed the regulator on the alternator that was on the engine, and have now changed the alternator itself, I've come around to thinking that the Adverc is the thing that is at fault, so I've now disconnected that leaving the charging system relying on the regulator fitted to the alternator. Anyone got any views of anything else that could have been at fault?

 

Any solar, and how well charged are the batteries? I think that we have discussed this before. I have had this with very well charged batteries and solar still charging them. It can shut some alternators down.

 

It could be high resistance between the battery and charge warning lamp, causing the voltage at the warning lamp to be less than that in the alternator., but usually that is just a low glow on the lamp.

 

I think an open circuit field diode could do that as well.

Edited June 3 by Tony Brooks

[Wanderer Vagabond]

1 hour ago, Tony Brooks said:

 

Any solar, and how well charged are the batteries? I think that we have discussed this before. I have had this with very well charged batteries and solar still charging them. It can shut some alternators down.

 

It could be high resistance between the battery and charge warning lamp, causing the voltage at the warning lamp to be less than that in the alternator., but usually that is just a low glow on the lamp.

 

I think an open circuit field diode could do that as well.

The battery meter reckons that the batteries are 90% charged when I start in the morning, but that is open to question since it is still charging at 28 amps whereas once fully charged, the charging rate goes down to 9 amp or less. Tonight when I switched off the charge rate was down to 12 amps. We have no solar (we decided that when we needed it, during the winter, there was insufficient daylight hours but then during the summer with loads of daylight hours we also travelled a lot, so didn't really need it).

 

The reason that I am now questioning the Adverc is because now, when replacing the alternator for at least the 5th time, I realised that I had never replaced the starter battery alternator, and that isn't connected to the Adverc. Originally I'd put the regular domestic alternator replacements down to the engine environment in which the alternators are, not much air circulation, pretty warm etc. and obviously that it does more work than the engine alternator. Now I'm starting to question that assumption. I seem to recall in the dim and distant past when I had an electrician working on yet another failed alternator he said something along the lines of,"You know that an Adverc can invalidate the alternator warranty ", and it was after that I believed that it had been disconnected. I'm not reporting that as fact, merely what the electrician had said, which may or may not be correct.

 

So now, having disconnected, and removed, the Adverc (which is now 12 years old) I'm going to see what happens tomorrow on my 7 mile run back to my mooring. On previous experience that should be plenty long enough for the ignition warning light to come on, if it is going to. The green overvoltage lamp was connected to the Adverc so that now doesn't come on when I start the engine (although the ignition light does, and goes out when the engine fires). I'll keep a regular eye on the charge rate and the voltage as we go along to see if anything untoward happens. 

[blackrose]

I've ordered one of these

 

https://amzn.eu/d/b9G7AWT

 

Mainly because if it's not right I can just return it FOC to Amazon. 

 

Apart from mountings and pulleys I assume it will be electrically compatible with my existing alternator and I can just swap the connections over.

Edited June 3 by blackrose

[Tony Brooks]

33 minutes ago, Wanderer Vagabond said:

The battery meter reckons that the batteries are 90% charged when I start in the morning, but that is open to question since it is still charging at 28 amps whereas once fully charged, the charging rate goes down to 9 amp or less. Tonight when I switched off the charge rate was down to 12 amps. We have no solar (we decided that when we needed it, during the winter, there was insufficient daylight hours but then during the summer with loads of daylight hours we also travelled a lot, so didn't really need it).

 

The reason that I am now questioning the Adverc is because now, when replacing the alternator for at least the 5th time, I realised that I had never replaced the starter battery alternator, and that isn't connected to the Adverc. Originally I'd put the regular domestic alternator replacements down to the engine environment in which the alternators are, not much air circulation, pretty warm etc. and obviously that it does more work than the engine alternator. Now I'm starting to question that assumption. I seem to recall in the dim and distant past when I had an electrician working on yet another failed alternator he said something along the lines of,"You know that an Adverc can invalidate the alternator warranty ", and it was after that I believed that it had been disconnected. I'm not reporting that as fact, merely what the electrician had said, which may or may not be correct.

 

So now, having disconnected, and removed, the Adverc (which is now 12 years old) I'm going to see what happens tomorrow on my 7 mile run back to my mooring. On previous experience that should be plenty long enough for the ignition warning light to come on, if it is going to. The green overvoltage lamp was connected to the Adverc so that now doesn't come on when I start the engine (although the ignition light does, and goes out when the engine fires). I'll keep a regular eye on the charge rate and the voltage as we go along to see if anything untoward happens. 

 

As a matter of interest, how many charge warning lamps do you have? If only one, then that makes diagnostics harder, so you will have to rely on volt meter readings for each alternator to identify a faulty one. However, disconnecting the Adverc should prove if it is the culprit - as you say.

 

Of all the advanced alternator controllers available a number of years ago, the one least likely to wreck the alternator is the Adverc, because it shuts itself down on a 15-minute cycle and that will let the alternator cool down, but many vendors are likely to take any opportunity to void a warrantee.

 

 

[Wanderer Vagabond]

3 minutes ago, Tony Brooks said:

 

As a matter of interest, how many charge warning lamps do you have? If only one, then that makes diagnostics harder, so you will have to rely on volt meter readings for each alternator to identify a faulty one. However, disconnecting the Adverc should prove if it is the culprit - as you say.

 

Of all the advanced alternator controllers available a number of years ago, the one least likely to wreck the alternator is the Adverc, because it shuts itself down on a 15-minute cycle and that will let the alternator cool down, but many vendors are likely to take any opportunity to void a warrantee.

 

 

There are separate charge warning lamps for the domestic and the engine alternators. Have to say that I'm rather glad of that since the engine warning light is attached to a warning buzzer whereas the domestic alternator warning light isn't. Back in 2020 when coming back from the Nene through Northampton the domestic alternator failed (again) and I managed to disengage the alternator entirely (removed the drive belt) and took the boat back to Braunston with a jump lead between the domestic and engine batteries which kept the domestic batteries charged by the engine alternator (thereby by-passing the Adverc). I disconnected the jump lead when starting up so that the starter motor wouldn't be drawing from the domestic batteries. I think it would have 'done my head in' if I'd had the warning buzzer sounding all the way.