HELP NEEDED : Kestrel External Alternator Controller (Made by Acorn - Obsolete)

[alan_fincher]

We have a few problems(!)

 

Does anybody have a machine readable copy of the manual and installation document for a Kestrel Alternator Controller please? (It used to be available on the Acorn site as K90_installation.doc, but no longer is, unfortunately.)

 

Failing that, I believe it is possible to disable one without physically removing it, such that it no longer overrides the alternator's own internal controller. I think this can be done by disconnecting one wire and leaving everything else alone.

 

Does anybody know how to do it, as we are currently frying our batteries, and I don't know if the Kestrel has gone wrong or something else. I want to eliminate the Kestrel from the list of possibles.

 

Any help gratefully received.

[Tony Brooks]

Yes. as far as I know its just like all the rest apart form the Sterling A to B. There will be an extra wire hanging out of the back of the alternator that connects to the Kestrel. Just disconnect this wire and the Kestrel will no longer be able to short the internal regulator out so the internal regulator will just get on with its job.

 

If the Kestrel was fitted to overcome deficiencies in the charging circuit like split charge diodes and undersized wiring then those items need addressing as well.

[raymondh]

Acorn still going, so call 0161 336 2680 Peter Hopley or http://www.acornengineer.co.uk/

 

Ray

[alan_fincher]

Thank you Tony.

 

That's actually one of the few things we didn't try in a wet dark engine room in a thunderstorm, but too late to try tonight now.

 

However I did manage to turn up a manual for the Kestrel, (it seems I scanned one in some time ago), and I'm fairly certain it can be disabled by either....

 

1) Keeping the test button on the side held in

2) Breaking the feed from the relay that energises it, when the alternator switch is turned on.

 

Trying either of the above, (particularly the second, as I'm more confident it is disabled that way), we are still seeing excess voltage being delivered to the battery bank (typically 15.5V at good charging revs), so it seems to me it is the internal regulator on the alternator that is "goosed". In fact I don't think the Kestrel is kicking in at all - certainly the green light that should be on when it has taken over doesn't seem to be.

 

I had hoped it was a Kestrel fault, and we could take it out of circuit. No such luck it seems.

 

It is something like an AC5R of the type that used to have an external regulator box, but has been modified in the to have an internal one instead. I'm wondering now where I can track down another internal regulator quickly, (but also, of course, what has caused the current one to fail).

 

Thanks for the help - we will look at that suggestion tomorrow, but I'm not now hopeful, I'm afraid.

Acorn still going, so call 0161 336 2680 Peter Hopley or http://www.acornengineer.co.uk/

 

Ray

 

Thanks, but have now found scans of the docs.

 

Peter Hopley seems to have now removed it from the Acorn site, where it was last time I looked, so I kind of assume is no longer interested in this rather obsolete product.

[David Schweizer]

To be honest Alan, I would dump the Kestrel and install a more up to date digital alternator regulator.

 

In it's day the Kestrel was an inovation, but it was never upgraded, and has been left behind by more modern electronics. As you know. I like the Sterling Advanced Digital Alternator Controller, although the one fitted to Helvetia must be something like 15 years old now, and has been superseded several times, but still does a good job.

[Tony Brooks]

 

 

 

Trying either of the above, (particularly the second, as I'm more confident it is disabled that way), we are still seeing excess voltage being delivered to the battery bank (typically 15.5V at good charging revs), so it seems to me it is the internal regulator on the alternator that is "goosed". In fact I don't think the Kestrel is kicking in at all - certainly the green light that should be on when it has taken over doesn't seem to be.

 

 

Not necessarily, assuming it shorts out the internal regulator. If there is a short of some kind on the extra wire from the alternator and assuming its a negative switched rotor then it would give a high charging voltage but I would have expected a lot higher than 15.5 volts at reasonable revs.

 

AC5 sounds like a CAV alternator to me and they had a wander lead and plug that was used on the external regulator to set the charging voltage. No idea how one would or would want to fit an internal regulator or if would have such a facility. Over to SirN.

 

I think the CAV AC series were 9 diode machines so a blown field diode could cause an excess charging voltage but the warning lamp may well glow.

[Sir Nibble]

AC5R. Pull the green wire off the brush holder to disable the regulator and hand control back to the kestrel. I can supply a new regulator if needed.

[alan_fincher]

Excellent.

 

So to be clear, if the Kestrel isn't "borked" it can operate even if the AC5's internal regulator is?

 

We will try that, as soon as we have had essential coffee and breakfast.

 

The alternator still has one of those industrial heavy metal cases enclosing the end, so is a bugger to get into. (Yes, I know you previously advised me to ditch it, but I wasn't brave enough to leave quite as many bits of uninsulated electrics vulnerable to the first metal object that might find its way too close to them.).

 

Are there any simple "meter" tests we can do on the regulator that might indicate it is definitely knackered?

 

Is it possible it is the "enclosedness" of this end of the alternator that may be causing bits to fail?

 

I'm already fairly certain we will need a new a regulator, and quite quickly, so I'm likely to be in touch!

[alan_fincher]

To be honest Alan, I would dump the Kestrel and install a more up to date digital alternator regulator.

 

In it's day the Kestrel was an inovation, but it was never upgraded, and has been left behind by more modern electronics. As you know. I like the Sterling Advanced Digital Alternator Controller, although the one fitted to Helvetia must be something like 15 years old now, and has been superseded several times, but still does a good job.

 

 

Yes, I know that the Kestrel is a well obsolete product with less science than the modern equivalents.~

 

However there is so much to do on this boat that I have not invested effort and money into what until now seemed to be doing a good enough job.

 

I think it's fair to say we don't yet know for certain what has happened, and whether the Kestrel has played any part in what has happened.

 

Ideally I'd prefer not to have an external controller at all - I have not had one on other boats. Whether it is really required here I don't know - maybe it is because the AC5 is an older type not able to put out the volys of something like a more modern A127?

 

I can't help feeling given what the alternator controllers cost the money might be better spent on just buying a more modern alternator, though I seem to recall some felt there were good reasons why I should retain theAC5 on this fairly slow revving engine.

 

Our immediate issue is to get moving again by any fudge, and I'm not in a position to make major changes miles from the mooring with a depleting battery bank!

[pete.i]

As far as I can tell all the Kestrel did was bump up the charging voltage to around 14.4 ish volts when alternator regulators only allowed 13.8 volts. I changed the regulator on my alternator for one that gave out 14.4 volts and ditched my Kestrel. If you have the manual the connection diagram is in there and it is easy enough to take it out when you get back to a mooring. In the meantime as has been said cut the wire from the alternator to the kestrel. I cannot remember whether the Kestrel had anything to do with the split charging circuit so you might have to be careful with that side of things. ( I said "I CANNOT REMEMBER" before people jump down my throat) I don't think it has though. I completely removed mine when I got s decent charging voltage from my alternator and fitted a VSR to handle the split charging best thing I did on my boat. Personally I wouldn't use any fangled machine to sort out the charging but that is just me.

[Sir Nibble]

There's a thing. Just happen to have one lying about.

[alan_fincher]

OK, David and I have spent a long while in the engine room in increasing desperation, but with zero success.

 

 

There will be an extra wire hanging out of the back of the alternator that connects to the Kestrel. Just disconnect this wire and the Kestrel will no longer be able to short the internal regulator out so the internal regulator will just get on with its job

 

 

No improvement - charging voltage remains excessive, as it has done with any other method used to attempt to stop the Kestrel interfering. I'm fairly convinced the regulator on the alternator is buggered.

 

AC5R. Pull the green wire off the brush holder to disable the regulator and hand control back to the kestrel.

 

Assuming you mean the actual green wire with a spade coming from the internal regulator, then disconnecting this results in no charging at all. The Kestrel does not seem to function.

I am increasingly convinced the Kestrel is not working either, as it is supposed to have a green light showing when it is, and whatever we do, if the Kestrel is energised the green light never comes on. This is normally obscured, so I don't know if it ever has, or, if it has, when it stopped. Pressing the reset button doesn't bring it on. We have tried medasuring the voltage across the non working green light, in case it is an LED failure, but there seems to be none.

 

We have probably gone a step too far, but the Kestrel also has an internal potentiometer that you are supposed to adjust to get the correct charging cut out point. It seemed wrong, so reluctantly we have tweaked it. It is now showing the correct voltage across two test points, but still the green light stays off, and charging voltages all to pieces, I think not because Kestrel is working, but because internal regulator is not. I suspect we should have left this adjustment alone, as other factors are causing the anomaly, but we were desperate, and have done it now.

 

All out of ideas, beyond trying a new regulator on the AC5, unless someone can suggest any tests that I can do with a meter on the existing one to demonstrate if it is likely dead.

Thanks for all help and advice.

Snibs - I'll PM you.

[MoominPapa]

At least you have control of charging again. Connect the wire from the regulator in the morning when the batteries are discharged and let it charge them up to 14.6 volts or so. By then they should be 80% plus charged. Then disconnect the wire to avoid overcharging. Should be enough to get you home without the lights going going out or the batteries boiling.

 

 

MP.

[LEO]

As far as I can tell all the Kestrel did was bump up the charging voltage to around 14.4 ish volts when alternator regulators only allowed 13.8 volts. I changed the regulator on my alternator for one that gave out 14.4 volts and ditched my Kestrel. If you have the manual the connection diagram is in there and it is easy enough to take it out when you get back to a mooring. In the meantime as has been said cut the wire from the alternator to the kestrel. I cannot remember whether the Kestrel had anything to do with the split charging circuit so you might have to be careful with that side of things. ( I said "I CANNOT REMEMBER" before people jump down my throat) I don't think it has though. I completely removed mine when I got s decent charging voltage from my alternator and fitted a VSR to handle the split charging best thing I did on my boat. Personally I wouldn't use any fangled machine to sort out the charging but that is just me.

 

Pete,

 

Cruelty to Kestrels...............it's not so much the charging rate with these, but stimulating the alternator to charge when really all it wants to do is shut down.........I thought the units had a small screw accessible when they grey cover was removed that allowed adjustment of the shut off voltage.

 

I now have a Sterling unit and a 90 amp alternator and it gives good service.

 

Hope you are well...

 

Mike.

 

PS OOps I see Alan has found the small adjuster.....

[Sir Nibble]

There was a six diode AC7. Six and nine looked identical but didn't work if you fitted the wrong one. Ask me how I know.

 

 

 

 

 

Not necessarily, assuming it shorts out the internal regulator. If there is a short of some kind on the extra wire from the alternator and assuming its a negative switched rotor then it would give a high charging voltage but I would have expected a lot higher than 15.5 volts at reasonable revs.

 

AC5 sounds like a CAV alternator to me and they had a wander lead and plug that was used on the external regulator to set the charging voltage. No idea how one would or would want to fit an internal regulator or if would have such a facility. Over to SirN.

 

I think the CAV AC series were 9 diode machines so a blown field diode could cause an excess charging voltage but the warning lamp may well glow.

[Tony Brooks]

That's why I said over to you. I have only dealt with the AC series on MOD stuff and know my knowledge is very limited.