Converting alternator

[Bro]

I believe there may have been topic on posibility of converting machine sensed alternators to battery sensed but my search reveals nothing. Shall be grateful if someone will give me a lead to such topic on the forum should it exist.

 

Not that I know much about it but I believe a battery sensed alternator would give high charge rate for longer period than machine sensed and if so then possibly converting from one to the other would be advantageous (?).

 

Thanks.

Alan

[Arnot]

I believe there may have been topic on posibility of converting machine sensed alternators to battery sensed but my search reveals nothing. Shall be grateful if someone will give me a lead to such topic on the forum should it exist.

 

Not that I know much about it but I believe a battery sensed alternator would give high charge rate for longer period than machine sensed and if so then possibly converting from one to the other would be advantageous (?).

 

Thanks.

Alan

It is usually quite straightforward but it would help to know what alternator you have...

 

Regards

 

Arnot

[Biggles]

Gibbo has one way

 

http://www.smartgauge.co.uk/technical2.html#alt_mod

[Sir Nibble]

Gibbo has one way

 

http://www.smartgauge.co.uk/technical2.html#alt_mod

He probably has, but I can't find it by following your link, only the "diode in the sense lead" mod for raising regulated voltage.

If we can identify the alternator, it may be as simpler as changing the regulator, or surgery may be required. Something like a common or garden A127 it is a little bit of wiring and a relay.

[Tony Brooks]

I believe there may have been topic on posibility of converting machine sensed alternators to battery sensed but my search reveals nothing. Shall be grateful if someone will give me a lead to such topic on the forum should it exist.

 

Not that I know much about it but I believe a battery sensed alternator would give high charge rate for longer period than machine sensed and if so then possibly converting from one to the other would be advantageous (?).

 

Thanks.

Alan

 

 

As far as the advantages are concerned there are none as long as there is minimal resistance in the main charging circuit, both positive and negative side. All it does is counter any voltdrop between the alternator and batteries.

 

It was pretty much vital when we had split charge diodes but there are better ways to split the charge now.

[Guest]

As far as the advantages are concerned there are none as long as there is minimal resistance in the main charging circuit, both positive and negative side. All it does is counter any voltdrop between the alternator and batteries.

 

It was pretty much vital when we had split charge diodes but there are better ways to split the charge now.

Amen

[Arnot]

It was pretty much vital when we had split charge diodes but there are better ways to split the charge now.

 

Before that there were relays

 

Before that there were generators with load compensation

 

Before that there were pretty oil lamps

 

- what goes round comes round....

 

 

Regards

 

Arnot

[Bro]

As far as the advantages are concerned there are none as long as there is minimal resistance in the main charging circuit, both positive and negative side. All it does is counter any voltdrop between the alternator and batteries.

 

It was pretty much vital when we had split charge diodes but there are better ways to split the charge now.

 

 

Many thanks to all who responded.

 

Tony, if I understand correctly, you say there is no advantage in battery sensed operation compared to machine sensed (other than to counter volt drop between alternator and batteries) in which case I'm barking up the wrong tree and will desist.

 

Not being 'lectrical (strictly clockwork, me) I don't understand relevance of your reference to split charge diodes and splitting the charge.

 

Does it help if I say the alernator in question is a 100 amp Delco Remy fitted as standard equipment for domestic battery bank on my 3 year old 38 hp Beta Marine engine. The engine has 2nd alternator for engine start battery. My aim would be to speed the charging of domestic batteries (whilst the alternator kicks our 116 amps on start it settles to much lower rate more quickly than I would like). For further information the alternator seems to run at a steady indicated 14.4 to 14.2 volts regardless of amp output.

[Arnot]

Many thanks to all who responded.

 

Tony, if I understand correctly, you say there is no advantage in battery sensed operation compared to machine sensed (other than to counter volt drop between alternator and batteries) in which case I'm barking up the wrong tree and will desist.

 

Not being 'lectrical (strictly clockwork, me) I don't understand relevance of your reference to split charge diodes and splitting the charge.

 

Does it help if I say the alernator in question is a 100 amp Delco Remy fitted as standard equipment for domestic battery bank on my 3 year old 38 hp Beta Marine engine. The engine has 2nd alternator for engine start battery. My aim would be to speed the charging of domestic batteries (whilst the alternator kicks our 116 amps on start it settles to much lower rate more quickly than I would like). For further information the alternator seems to run at a steady indicated 14.4 to 14.2 volts regardless of amp output.

 

What was said was that there was no advantage in battery sensing if all the rest of the charging circuit was essentially perfect and this is absolutely true. However, in my experience the charging circuits on most narrow boats are, whilst perfectly safe and workable, not perfect.

 

There are a couple of benefits to battery sensing in most boats although the better the wiring the more mariginal they become. The first is that the majority of battery sensing systems allow the regulation voltage to be trimmed to match what the batteries best respond to. The second is that there can be a slight increase in the output of the alternator particularly at lower engine/alternator speeds.

 

When diode based split charge systems were more or less standard, a lot of them were not actually all that well designed and often they resulted in a significant reduction in the charging voltage available at the batteries. Using a battery sensing system allowed the alternator to correct this loss of voltage and restore effective battery charging. In your case, because you have a twin alternator installation, the costs and problems of split charging are neatly sidestepped.

 

For the average boater it is difficult to determine if battery sensing would provide any benefit as it requires some pretty good instrumentation and quite a bit of knowledge and experience. Even then the best improvements often come from the rectification of other issues identified whilst carrying out this evaluation so it is far from a universal upgrade.

 

In your case, the Delco alternators are usually quite tricky to convert to battery sensing and often don't take kindly to the extra heat that increased output generates in the windings. Since your regulated voltage is at a reasonable level and you don't report any problems with bat flatteries, my suggestion would be to leave well alone. Interestingly the characteristic of the charging current starting high and falling quickly is usually the indicator of an effective charging system and good batteries. If you converted your alternator it would probably develop maximum current for slightly longer and then fall off slightly more quickly and I doubt it would have much impact on how long it took to charge the batteries.

 

Hope this helps,

 

Regards

 

Arnot

[Sir Nibble]

I have found battery sensing to be considerably better than machine sensing because under heavy load the sensed voltage at D+ is often appreciably higher than the output voltage at B+. I have seen an extra 10A gained on a system that showed no volt drop worth mentioning at all on the wiring, maybe 0.02V ish, whilst the difference D+ to B+ was more in the order 0.2V!

[WotEver]

I have found battery sensing to be considerably better than machine sensing because under heavy load the sensed voltage at D+ is often appreciably higher than the output voltage at B+. I have seen an extra 10A gained on a system that showed no volt drop worth mentioning at all on the wiring, maybe 0.02V ish, whilst the difference D+ to B+ was more in the order 0.2V!

 

I'm confused by this. I'm absolutely no expert on alternators and charging - I'm happy to defer to Gibbo on all things battery related. My confusion stems from the apparently contradictory statements "a system that showed no volt drop worth mentioning at all on the wiring, maybe 0.02V ish" followed by "the difference D+ to B+ was more in the order 0.2V". If the drop is <0.02V then how can there be a drop of >0.2V? Where'd the other 0.18V come from? What am I missing?

 

Thanks,

Tony

[Sir Nibble]

I'm confused by this. I'm absolutely no expert on alternators and charging - I'm happy to defer to Gibbo on all things battery related. My confusion stems from the apparently contradictory statements "a system that showed no volt drop worth mentioning at all on the wiring, maybe 0.02V ish" followed by "the difference D+ to B+ was more in the order 0.2V". If the drop is <0.02V then how can there be a drop of >0.2V? Where'd the other 0.18V come from? What am I missing?

 

Thanks,

Tony

a system that showed no volt drop worth mentioning at all on the wiring, maybe 0.02V ish

That's the wiring alternator to battery.

the difference D+ to B+ was more in the order 0.2V

That's the D+ and B+ terminals on the alternator, whereby B+ is what the battery gets and D+ is what the regulator sees. So if you have a 14.2V regulator the actual output to the battery will be only 14V. It shouldn't happen that way, but it does unfortunately, wouldn't matter a toss on a vehicle (which is what the alternator is designed for) but when the intention is to get as much charge as possible into a big battery bank in the time available, it is quite an issue.

[Bro]

That's the wiring alternator to battery.

 

That's the D+ and B+ terminals on the alternator, whereby B+ is what the battery gets and D+ is what the regulator sees. So if you have a 14.2V regulator the actual output to the battery will be only 14V. It shouldn't happen that way, but it does unfortunately, wouldn't matter a toss on a vehicle (which is what the alternator is designed for) but when the intention is to get as much charge as possible into a big battery bank in the time available, it is quite an issue.

 

 

Again, many thanks to those who have contributed. What with D+, B+ and suchlike now getting into the topic it's becomming a bit techie for me (though interesting) so, based on Arnot's comments (in particular the difficulty and reliability issues raised) I have decided to leave well alone. What I will do however is check the volt drop between alternator and battery terminals and make better if too high.

[Sir Nibble]

Again, many thanks to those who have contributed. What with D+, B+ and suchlike now getting into the topic it's becomming a bit techie for me (though interesting) so, based on Arnot's comments (in particular the difficulty and reliability issues raised) I have decided to leave well alone. What I will do however is check the volt drop between alternator and battery terminals and make better if too high.

You ideally want to do that when the alternator is working hard and driving maximum current.

[KenK]

Again, many thanks to those who have contributed. What with D+, B+ and suchlike now getting into the topic it's becomming a bit techie for me (though interesting) so, based on Arnot's comments (in particular the difficulty and reliability issues raised) I have decided to leave well alone. What I will do however is check the volt drop between alternator and battery terminals and make better if too high.

 

My Beta 38 has Iskra alternators fitted, the domestic was originally a machine sensed but Beta supply an alternator controller and brush box conversion which turns it into a battery sensed amongst other things. Might be worth asking them if you do find it necessary.

 

Ken

[Bro]

My Beta 38 has Iskra alternators fitted, the domestic was originally a machine sensed but Beta supply an alternator controller and brush box conversion which turns it into a battery sensed amongst other things. Might be worth asking them if you do find it necessary.

 

Ken

 

Thanks Ken. Beta confirmed my alternator is Delco machine sensed but say they do not offer conversion. Wonder why they think it worthwhile for Iskra but not Delco.

[Arnot]

Thanks Ken. Beta confirmed my alternator is Delco machine sensed but say they do not offer conversion. Wonder why they think it worthwhile for Iskra but not Delco.

On the Iskra, you can just change the regulator which is screwed to the back of the alternator frame and then add the sense wire to the battery bank, easy peasy, you don't even have to remove the alternator from the engine.

 

On the Delco, you have to remove the alternator from the engine, completely strip it down, replace the internal regulator, modify the case with grinder, reassemble the bits with a special tool and refit it. It sounds worse than it is as long as you are well practiced at it but there are loads of easy mistakes to make that will be terminally detrimental to it's well being! If you really want a Delco alternator modified to B/S then its best to take it to a rebuilder - honest.

 

Just as a thought, some of the delco's are already battery sensed but wired up to make them machine sensed. If you post a piccy of the back of your alternator this might show up.

 

Regards

 

Arnot

[Bro]

Just as a thought, some of the delco's are already battery sensed but wired up to make them machine sensed. If you post a piccy of the back of your alternator this might show up.

 

Regards

 

Arnot

 

 

Thanks Arnott. Likely to be a few days before I'm back at the boat to take "piccy" but will do and would be grateful then for your further comments.

 

Regards

[Bro]

Just as a thought, some of the delco's are already battery sensed but wired up to make them machine sensed. If you post a piccy of the back of your alternator this might show up.

 

Regards

 

Arnot

 

I've got piccy but can't find out how to attach to this mail! Perhaps it's not needed anyway. There are just two terminals on the alternator, B+ and D+.

 

B+ has a heavy cable (50 mm) taking current to batteries and also a much smaller cable (green and yellow) from this same terminal. D+ has small cable (blue and yellow) same size as the green and yellow. There are no external boxes or gubbins of any sort on the alternator, back or sides. That's it!

 

Any use?

[Arnot]

I've got piccy but can't find out how to attach to this mail! Perhaps it's not needed anyway. There are just two terminals on the alternator, B+ and D+.

 

B+ has a heavy cable (50 mm) taking current to batteries and also a much smaller cable (green and yellow) from this same terminal. D+ has small cable (blue and yellow) same size as the green and yellow. There are no external boxes or gubbins of any sort on the alternator, back or sides. That's it!

 

Any use?

It sounds as though your alternator is only convertable by stripping it down but if you want to e-mail the piccy to me directly (details in profile), I could probably give you a definitive answer.

 

The small green/yellow is possibly a bettery sense wire already in the harness but from my experience you are still better running a new one...

 

Regards

 

Arnot