Alternator - questions

[Greybeard]

Hi

 

There is currently an A127/65 alternator fitted and I'm looking to fit a Sterling AB12160 alternator - battery charger.

 

I've sourced a bosch which can be upgraded to 120a for about £150 which should have same mountings.

 

Is there any mods I should ask for on the alternator and is 120a ok to run the AB12160?

 

Thanks.

[PaulG]

Did someone mention electrics?

 

[chris w]

Hi

 

There is currently an A127/65 alternator fitted and I'm looking to fit a Sterling AB12160 alternator - battery charger.

 

I've sourced a bosch which can be upgraded to 120a for about £150 which should have same mountings.

 

Is there any mods I should ask for on the alternator and is 120a ok to run the AB12160?

 

Thanks.

 

The alternator will need no mods to operate with the AB12160. Any particular reason you are going for the AB12160 rather than the PDAR digital alternator regulator? The latter is less expensive and will charge faster than the AB12160 (although there is a small mod - an additional wire - needed on the alternator)

 

Chris

[PaulG]

Hi

 

There is currently an A127/65 alternator fitted and I'm looking to fit a Sterling AB12160 alternator - battery charger.

 

I've sourced a bosch which can be upgraded to 120a for about £150 which should have same mountings.

 

Is there any mods I should ask for on the alternator and is 120a ok to run the AB12160?

 

Thanks.

 

I'd check to see that the bigger alternator will actually give you an improvement before fitting the bigger alternator. Your 65A alternator should comfortably supply 40A continuously.

 

Depending on the type of battery, the charge rate should not be much more than 10-15% of the capacity of the battery bank. So unless your battery bank is significantly bigger than approx 300 aH (Wet Plate) / 400 aH (AGM), you're not going to see much improvement in charging time.

 

(Chris/Gibbo, please feel free to explain/correct my figures - I'm not going to take offence!)

[Greybeard]

The alternator will need no mods to operate with the AB12160. Any particular reason you are going for the AB12160 rather than the PDAR digital alternator regulator? The latter is less expensive and will charge faster than the AB12160 (although there is a small mod - an additional wire - needed on the alternator)

 

Chris

 

Hi Chris

 

Missed the PDAR and you're right it's about 170 sovs cheaper. A beer(at least) for your good self if we ever meet!!!!

 

An additional wire?

 

I'm using ceo sales who seem to know what they're talking about.

 

For a further beer could you detail what and where this wire goes please and I can pass on the details unless it's something I can do myself?

 

Thanks

 

 

 

I'd check to see that the bigger alternator will actually give you an improvement before fitting the bigger alternator. Your 65A alternator should comfortably supply 40A continuously.

 

Depending on the type of battery, the charge rate should not be much more than 10-15% of the capacity of the battery bank. So unless your battery bank is significantly bigger than approx 300 aH (Wet Plate) / 400 aH (AGM), you're not going to see much improvement in charging time.

 

(Chris/Gibbo, please feel free to explain/correct my figures - I'm not going to take offence!)

 

 

Hi

 

Bank will be 480 - 540 wet - depends on best price for batteries i.e. 4 x 120ah or 4 x 135ah

 

Love the pic by the way. Would look good on side of boat............better than Barbie or Pokemon suggested by hoolies!!!!!!!!!!!

[chris w]

Hi Chris

 

Missed the PDAR and you're right it's about 170 sovs cheaper. A beer(at least) for your good self if we ever meet!!!!

 

An additional wire?

 

I'm using ceo sales who seem to know what they're talking about.

 

For a further beer could you detail what and where this wire goes please and I can pass on the details unless it's something I can do myself?

 

Thanks

 

You need to solder a wire to the one of the brushes in the alternator's regulator. One brush will be connected to the D+ wire and there will be zero ohms between the D+ connector on the regulator and the D+ brush. Having identified that brush you want the OTHER one.

 

A wire needs to be soldered to the metal connection at the top of this other brush. Leave it about 4" inches long. This connects to the white (field wire) on the Sterling PDAR. A crimp connection is a good idea for joining these two wires together as you can then separate them at will and actually see the difference in charging current with the PDAR connected and disconnected.

 

It's a doddle on the A127 alternator. Be careful in taking the regulator off and putting it back into the alternator. Especially putting it back, do NOT force it in or you will break the brushes. Just very gently jiggle it till it suddenly drops back in. I have no experience with the Bosch alternator but it should be the same in principle.

 

Chris

 

I'd check to see that the bigger alternator will actually give you an improvement before fitting the bigger alternator. Your 65A alternator should comfortably supply 40A continuously.

 

Depending on the type of battery, the charge rate should not be much more than 10-15% of the capacity of the battery bank. So unless your battery bank is significantly bigger than approx 300 aH (Wet Plate) / 400 aH (AGM), you're not going to see much improvement in charging time.

 

(Chris/Gibbo, please feel free to explain/correct my figures - I'm not going to take offence!)

 

The larger alternator will give a significant improvement in charging time. For a standard NB pulley set up (2:1 ratio) the most you will get out of your alternator will be about 60% of the nominal current. So a 65A alternator will deliver about 40A max. It will not do this continuously though....only at the very beginning of the charge cycle because, once the battery terminal voltage starts to rise, the current will fall. An alternator controller will not increase this maximum available current - it will, though increase the time for which you get any particular current.

 

The 120A alternator will deliver about 70-75A at typical NB revs and so will significantly decrease the charge time as compared to the A127 you have. Its output too will fall as the bateries charge, just as with the smaller alternator. All other things being equal, you will see your charge times drop by about 40% with the larger alternator.

 

So long as you regularly check the water levels in the batteries, you could charge a big bank like that at 200A if you wanted too.

 

Chris

Edited April 14, 2008 by chris w

[Greybeard]

You need to solder a wire to the one of the brushes in the alternator's regulator. One brush will be connected to the D+ wire and there will be zero ohms between the D+ connector on the regulator and the D+ brush. Having identified that brush you want the OTHER one.

 

A wire needs to be soldered to the metal connection at the top of this other brush. Leave it about 4" inches long. This connects to the white (field wire) on the Sterling PDAR. A crimp connection is a good idea for joining these two wires together as you can then separate them at will and actually see the difference in charging current with the PDAR connected and disconnected.

 

It's a doddle on the A127 alternator. Be careful in taking the regulator off and putting it back into the alternator. Especially putting it back, do NOT force it in or you will break the brushes. Just very gently jiggle it till it suddenly drops back in. I have no experience with the Bosch alternator but it should be the same in principle.

 

Chris

 

 

 

The larger alternator will give a significant improvement in charging time. For a standard NB pulley set up (2:1 ratio) the most you will get out of your alternator will be about 60% of the nominal current. So a 65A alternator will deliver about 40A max. It will not do this continuously though....only at the very beginning of the charge cycle because, once the battery terminal voltage starts to rise, the current will fall. An alternator controller will not increase this maximum available current - it will, though increase the time for which you get any particular current.

 

The 120A alternator will deliver about 70-75A at typical NB revs and so will significantly decrease the charge time as compared to the A127 you have. Its output too will fall as the bateries charge, just as with the smaller alternator. All other things being equal, you will see your charge times drop by about 40% with the larger alternator.

 

So long as you regularly check the water levels in the batteries, you could charge a big bank like that at 200A if you wanted too.

 

Chris

 

Chris

 

Thanks very much for the advice.

 

Mike

[PaulG]

The larger alternator will give a significant improvement in charging time. For a standard NB pulley set up (2:1 ratio) the most you will get out of your alternator will be about 60% of the nominal current. So a 65A alternator will deliver about 40A max.

 

It will not do this continuously though....only at the very beginning of the charge cycle because, once the battery terminal voltage starts to rise, the current will fall. An alternator controller will not increase this maximum available current - it will, though increase the time for which you get any particular current.

 

I said the alternator could "supply" 40A continuously, not "charge at" 40 A continuously. Alternators are usually derated because they are badly cooled, and I think most pulley ratios are chosen with this in mind. It should actually be capable of supplying the full rated output for short periods.

 

The 120A alternator will deliver about 70-75A at typical NB revs and so will significantly decrease the charge time as compared to the A127 you have. Its output too will fall as the bateries charge, just as with the smaller alternator. All other things being equal, you will see your charge times drop by about 40% with the larger alternator.

 

But only at the start of the charging process. There comes a point where the current curves of identical batteries being charged by either alternator converge, in this case at 40A, and from then on the charge rate is the same regardless of which alternator is used.

 

So, IMHO, I don't think you will get anything like 40% improvement.

 

So long as you regularly check the water levels in the batteries, you could charge a big bank like that at 200A if you wanted too.

 

Er, maybe. But I wouldn't recommend it.

Edited April 14, 2008 by PaulG

[chris w]

I said the alternator could "supply" 40A continuously, not "charge at" 40 A continuously. Alternators are usually derated because they are badly cooled, and I think most pulley ratios are chosen with this in mind. It should actually be capable of supplying the full rated output for short periods.

 

I'm sure the alternator would be capable of delivering its full rated output continuously, it's just that you'll never see it on a NB with a 2:1 pulley ratio.

 

But only at the start of the charging process. There comes a point where the current curves of identical batteries being charged by either alternator converge, in this case at 40A, and from then on the charge rate is the same regardless of which alternator is used.

 

So, IMHO, I don't think you will get anything like 40% improvement.

Well, firstly the bulk stage will be different for the two alternators as they supply constant current during this phase. So one will be supplying around 75A and the other 40A. This will last around an hour so that's already a lot more AHs going in.

 

Secondly, because Mike is going to use an alternator controller, the charging voltage will be 14.8v and not around 14.3v (as for a typical internal regulator). Ergo, the higher current situation will obtain for much longer during the absoption stage. ie: the 75A alternator will be delivering a higher current than the 40A alternator for most of the absorption stage - nearly double the current at any particular point in time. One can't say precisely what the improvement will be of course without taking real measurements but it should be in the region of 40%.

 

 

Er, maybe. But I wouldn't recommend it.

 

Er... why not? It won't damage the batteries. The 10%-15% charge rate is for sealed gel batteries. It's one of the big advantages of wet-cells that they can be charged at much higher rates.

 

Chris

[PaulG]

I'm sure the alternator would be capable of delivering its full rated output continuously, it's just that you'll never see it on a NB with a 2:1 pulley ratio.

 

Most alternators would get a bit toasty if run at much more than 70% of their rated output for any length of time. This is a generalisation, but it is sensible to de-rate them regardless of pulley ratios.

 

Well, firstly the bulk stage will be different for the two alternators as they supply constant current during this phase. So one will be supplying around 75A and the other 40A. This will last around an hour so that's already a lot more AHs going in.

 

Secondly, because Mike is going to use an alternator controller, the charging voltage will be 14.8v and not around 14.3v (as for a typical internal regulator). Ergo, the higher current situation will obtain for much longer during the absoption stage. ie: the 75A alternator will be delivering a higher current than the 40A alternator for most of the absorption stage - nearly double the current at any particular point in time. One can't say precisely what the improvement will be of course without taking real measurements but it should be in the region of 40%.

 

No, you can't say exactly what the improvement will be. As it's not linear, I would expect the difference to be less than 40% (just my opinion), and if I was Mike I'd keep my 150 beer vouchers in my pocket and the skin on my knuckles until I'd tried the system with the existing alternator. On the other hand, perhaps there's some reason that he really needs a quick charge.

 

Er... why not? It won't damage the batteries. The 10%-15% charge rate is for sealed gel batteries. It's one of the big advantages of wet-cells that they can be charged at much higher rates.

 

Chris

 

Er... you hit the nail on the head when you added the qualifier about regularly checking electrolyte levels. It's all very well in theory, but in practice, how many people actually do? Ever lend your boat to a friend, and could you trust them to remember? What happens if the boat gets sold and the new owner doesn't appreciate the implications of such high charge rates?

 

I'd tend to err on the side of caution, that's all.

[Greybeard]

Most alternators would get a bit toasty if run at much more than 70% of their rated output for any length of time. This is a generalisation, but it is sensible to de-rate them regardless of pulley ratios.

 

 

 

No, you can't say exactly what the improvement will be. As it's not linear, I would expect the difference to be less than 40% (just my opinion), and if I was Mike I'd keep my 150 beer vouchers in my pocket and the skin on my knuckles until I'd tried the system with the existing alternator. On the other hand, perhaps there's some reason that he really needs a quick charge.

 

 

 

Er... you hit the nail on the head when you added the qualifier about regularly checking electrolyte levels. It's all very well in theory, but in practice, how many people actually do? Ever lend your boat to a friend, and could you trust them to remember? What happens if the boat gets sold and the new owner doesn't appreciate the implications of such high charge rates?

 

I'd tend to err on the side of caution, that's all.

 

I'm erring on the side of safety when it comes to the charging side of things........I'm not too sure that a standard charge would feed my power hungry kids.

 

The boat has sadly been just left to sit for the last 10 months by it's previous owners, can only be started with a power pack and after 90 minutes there wasn't enough charge in the batteries to run the lights.

 

The idea is to replace the batteries and put in a charging system which it hasn't got so by the time I've done this a few more quid for an alternator makes no difference but I can see your point.

 

I could try to use the existing alternator but I'll be spending the best part of a grand(probably more) in the engine hole on batteries, chargers and the like then I may as well go the whole hog.

 

I'd have to take the thing out anyway to do the mod for the PDAR - so it'll get sorted and used as a back up.

 

Battery maintenance is something I haven't done for donkeys years. I used to drive a 1.8 Vauxhall Viva that ate batteries.

 

Thanks for your advice.

 

Mike

[PaulG]

....I'm not too sure that a standard charge would feed my power hungry kids.

 

Ahh... That explains everything....you have my deepest sympathy. May the Lord have mercy on your wallet.

 

The boat has sadly been just left to sit for the last 10 months by it's previous owners...

 

The idea is to replace the batteries and put in a charging system which it hasn't got so by the time I've done this a few more quid for an alternator makes no difference but I can see your point.

 

The batteries are certainly U/S, and it's worth putting in a decent charging system to prevent your new ones from failing prematurely.

 

Good luck!

 

Paul

[PaulG]

Sorry, forgot to say that if you are installing the PDAR, don't forget to read Stuart's excellent installation guide on this forum:

 

http://www.canalworld.net/forums/index.php...mp;#entry208093

 

Cheers

 

Paul

[Chris Pink]

I'm not too sure that a standard charge would feed my power hungry kids.

 

No, but a bit of education might.

[Greybeard]

Sorry, forgot to say that if you are installing the PDAR, don't forget to read Stuart's excellent installation guide on this forum:

 

http://www.canalworld.net/forums/index.php...mp;#entry208093

 

Cheers

 

Paul

 

Nice one.

 

More goodies to buy...........I'm like a kid in a sweet shop

 

Thanks

 

No, but a bit of education might.

 

 

Are questioning my parental skills?

[Sir Nibble]

Alternators are usually derated because they are badly cooled,

Never heard of this. No idea how it would be achieved either. I hope you have a credible source for this piece of information 'cos my first reaction is that it is utter spheres.

[ditchcrawler]

Never heard of this. No idea how it would be achieved either. I hope you have a credible source for this piece of information 'cos my first reaction is that it is utter spheres.

 

Don't forget that alternators are normally mounted in engine bays with an airflow from the moving vehicle, not in hot engine rooms and under decks etc.

[Sir Nibble]

Don't forget that alternators are normally mounted in engine bays with an airflow from the moving vehicle, not in hot engine rooms and under decks etc.

Indeed. However, I still await the source for this de-rating information with some interest. Never heard of it before, still think it's a scrotum full.

[RLWP]

Don't forget that alternators are normally mounted in engine bays with an airflow from the moving vehicle, not in hot engine rooms and under decks etc.

 

I wouldn't be too sure of the beneficial environment in a motor vehicle. An alternator often has to live wedged between the block and the radiator, often not far from the exhaust. Nasty place an engine bay, electrical things die in there, batteries for instance.

 

Richard

[Yoda]

I can't think of a possible way of derating. It either works or its a fish.

[PaulG]

Never heard of this. No idea how it would be achieved either. I hope you have a credible source for this piece of information 'cos my first reaction is that it is utter spheres.

 

From memory it was Nick Billingham's book about narrowboat maintenance. I'll check next time I'm on the boat, 'cos that's where my copy is.

 

It does make sense, as most alternators were designed to charge automotive engine start batteries. High output only required for relatively short periods in a well-ventilated engine bay, therefore the cooling arrangements are fairly crude.

 

I know that my ageing Lucas 45A jobbie gets very hot if run at anything near full output for any length of time. I've adjusted my alternator controller to allow about 25A max, and it's fine now.

 

If you've got one of the modern, high output alternators, then it may well be cooled sufficiently to run at it's rated output for long periods.

[Sir Nibble]

From memory it was Nick Billingham's book about narrowboat maintenance. I'll check next time I'm on the boat, 'cos that's where my copy is.

 

It does make sense, as most alternators were designed to charge automotive engine start batteries. High output only required for relatively short periods in a well-ventilated engine bay, therefore the cooling arrangements are fairly crude.

 

I know that my ageing Lucas 45A jobbie gets very hot if run at anything near full output for any length of time. I've adjusted my alternator controller to allow about 25A max, and it's fine now.

 

If you've got one of the modern, high output alternators, then it may well be cooled sufficiently to run at it's rated output for long periods.

From memory it was Nick Billingham's book about narrowboat maintenance.

He's wrong.

It does make sense, as most alternators were designed to charge automotive engine start batteries. High output only required for relatively short periods in a well-ventilated engine bay, therefore the cooling arrangements are fairly crude.

Not so, a vehicle alternators main load is not the battery but the vehicles electrical system. Light, motors etc. Many vehicle engine bays are exremely hostile to alternators, even to the extent on some rovers of drawing the alternators cooling air from around the exhaust manifold.

 

The "marine" versions of vehicle alternators are usually only marinised by corrosion protection, certainly they take the same windings.

[PaulG]

From memory it was Nick Billingham's book about narrowboat maintenance.

He's wrong.

That's your opinion, which you are perfectly entitled to.

But, with all due respect, how many books on boat maintenance have you had published?

It does make sense, as most alternators were designed to charge automotive engine start batteries. High output only required for relatively short periods in a well-ventilated engine bay, therefore the cooling arrangements are fairly crude.

Not so, a vehicle alternators main load is not the battery but the vehicles electrical system. Light, motors etc.

But the "main load" is not the same as the "peak load", which will often be when all the items that you mentioned are on AND the battery is charging following an engine start.

Many vehicle engine bays are exremely hostile to alternators, even to the extent on some rovers of drawing the alternators cooling air from around the exhaust manifold.

 

I agree. But I the engineering manual for the alternator did not say "The alternator is designed so that the cooling air can be drawn from around the exhaust manifold".

[Sir Nibble]

That's your opinion, which you are perfectly entitled to.

But, with all due respect, how many books on boat maintenance have you had published?

 

But the "main load" is not the same as the "peak load", which will often be when all the items that you mentioned are on AND the battery is charging following an engine start.

 

 

I agree. But I the engineering manual for the alternator did not say "The alternator is designed so that the cooling air can be drawn from around the exhaust manifold".

That's your opinion, which you are perfectly entitled to.

But, with all due respect, how many books on boat maintenance have you had published?

How many tens of thousands of alternators marine industrial and vehicle has Mr Billingham overhauled? Has he noticed that the parts are the same for marine units? Does he know that alternators have no current regulation outside of the stator winding specification?

But the "main load" is not the same as the "peak load", which will often be when all the items that you mentioned are on AND the battery is charging following an engine start.

Rainy cold night. Lights 17A, wipers 6A heater 6A heated rear screen 8A engine and instruments 10A.

Total 47A, and it could be for HOURS.

I agree. But I the engineering manual for the alternator did not say "The alternator is designed so that the cooling air can be drawn from around the exhaust manifold".

'Twern't me that raised the issue of what an easy time alternators have in a vehicle as opposed to a boat, I was just refuting that.

 

Alternators, studied 'em, repaired and rebuilt AT LEAST tens of thousands, maybe hundreds of thousands, taught the principles in the classroom too.

Writing a book on boat maintenace does not make one an alternator expert, I know a great deal more about them than any car mechanic I have ever met and you'd think they'd know wouldn't you.

Over 30 years of working with alternators and I have never before heard of an alternator being de rated for any application.

He's wrong, in my humble but nonetheless extremely well informed opinion.

[PaulG]

How many tens of thousands of alternators marine industrial and vehicle has Mr Billingham overhauled? Has he noticed that the parts are the same for marine units? Does he know that alternators have no current regulation outside of the stator winding specification?

 

Rainy cold night. Lights 17A, wipers 6A heater 6A heated rear screen 8A engine and instruments 10A.

Total 47A, and it could be for HOURS.

'Twern't me that raised the issue of what an easy time alternators have in a vehicle as opposed to a boat, I was just refuting that.

 

Alternators, studied 'em, repaired and rebuilt AT LEAST tens of thousands, maybe hundreds of thousands, taught the principles in the classroom too.

Writing a book on boat maintenace does not make one an alternator expert, I know a great deal more about them than any car mechanic I have ever met and you'd think they'd know wouldn't you.

Over 30 years of working with alternators and I have never before heard of an alternator being de rated for any application.

He's wrong, in my humble but nonetheless extremely well informed opinion.

 

I'm not going to go down the "I know more about alternators than you do" route. I'm sure that you are very knowledgeable.

 

You asked me for a reference, and I gave you one. "He's wrong." is not a reasoned argument.

 

It doesn't matter how many alternators Nick Billingham has repaired, serviced, or otherwise fiddled with, it has nothing at all to do with whether he is right or wrong. [Caveat: it may not have been Nick Billingham - only my recollection]. I'm sure he's aware that marine units are essentially the same as automotive ones. Actually, that's the whole point. They were designed for automotive use, not marine. So, derate the unit for marine use - or, in other words, overspecify it.

 

Narrowboat engines are usually tucked away in a badly-ventilated box in the bottom of a slow-moving steel container. Automotive alternators, however, are usually contained in a box which is pretty much open at the bottom and front, and whizzes though the air at an average speed of 30 mph (according to the computer in my car). I recognise that this is a generalisation and that there will be badly designed vehicle installations, too.

 

Taking your power consumption example and transferring it into a marine situation, I would not recommend a 50A alternator to do the job. I'd suggest a 75A unit would be more reliable.