Battery chargers

[matthewd]

Hi,

 

I have searched on this topic so apologies if I've missed an answer in the haystack.

 

I was recently told that running the engine to charge the batteries may not fully charge them, and that special chargers exist which find exactly the right voltage to get them to 100% more efficiently. I suspect there may be a combination of truth and simplification in this..!

 

I have identified various mains chargers which appear to fit this description, but:

 

My question: if I am not charging from mains (I have no shore power) but only via the engine, does a charger exist which would fit between my alternators and the batteries to do the same thing? I.e. is there a better set-up than just alternators alone for charging from the engine?

 

Thanks for any suggestions

 

Matthew

[GUMPY]

Can someone pass the popcorn and beer please

 

 

 

 

 

 

 

 

 

 

Think you should start reading here

http://www.smartgauge.co.uk/controllers.html

Edited September 17, 2009 by idleness

[RobinJ]

I have searched on this topic so apologies if I've missed an answer in the haystack.

 

I was recently told that running the engine to charge the batteries may not fully charge them, and that special chargers exist which find exactly the right voltage to get them to 100% more efficiently. I suspect there may be a combination of truth and simplification in this..!

 

I have identified various mains chargers which appear to fit this description, but:

 

My question: if I am not charging from mains (I have no shore power) but only via the engine, does a charger exist which would fit between my alternators and the batteries to do the same thing? I.e. is there a better set-up than just alternators alone for charging from the engine?

There is no simple yes or no answer to this question!

Modern alternators are normally quite good and generally come with multi stage controllers, older ones do not, even so, run for long enough they should get batteries to over 90% charged.

It also depends on what type and how many batteries you have, but multi bank battery controllers of various descriptions are available to accomplish a variety of things, many of these handle inputs from mains devices, alternators, solar cells and wind generators too.

If you have a system which includes an inverter for appliances then it may mean there is an advantage to fitting some sort of controller which should improve charge rate and get the batteries to 100% quicker, however without a shore line, or a genny, there is no substitute for cruising!

[Gibbo]

http://www.smartgauge.co.uk/controllers.html

 

Gibbo

[Sir Nibble]

Oh my!

Tell us what batteries and alternators you have and within a week or two of argument a consensus will appear on how best to optimise your charging system. It is certainly possible to charge as well from alternators as from a charger, but some fiddling may be required.

[Gibbo]

Tell us what batteries and alternators you have and within a week or two of argument a consensus will appear on how best to optimise your charging system. It is certainly possible to charge as well from alternators as from a charger, but some fiddling may be required.

 

Is Chris W back?

 

Gibbo

[Sir Nibble]

Is Chris W back?

 

Gibbo

Look, if it were left to you and I and a handful of others we would be there in an afternoon, but I am sure you are as familiar as I am with being told you are a fool by someone who has read a book.

 

Wonder if this chap wants to "road test" an alternator paralleling system?

[Proper Job]

You mean that I can't do it with a hamster wheel and my old bike dynamo

[RobinJ]

Wonder if this chap wants to "road test" an alternator paralleling system?

You mean that I can't do it with a hamster wheel and my old bike dynamo

Parallel hamsters eh!

[matthewd]

OK, I did anticipate that anything to do with charging seems to be a minefield on this forum. I hope you appreciate it's not always easy to see whether the question you're asking has already been answered!

 

If I understand the article correctly, with modern alternator(s) and no mains charging it's unlikely that there would be any benefit from a separate charger. I assume my alternator charges at around 14.4v as I have measured that voltage on the batteries while the engine is running.

 

So thanks for the speedy response. I can respond with make and model of batteries and alternators but I don't want to waste anyone's time!

 

Matt

[David Schweizer]

http://www.smartgauge.co.uk/controllers.html

 

Gibbo

I have read your page, and understand what you are saying, I also recall the various "debates" which taken place over the years on exactly this subject. My experience has been that the Sterling Alternator regulator fitted to the systam on our boat does appear to reduce the charging time significantkly.

 

What I have never been able to establish is whether, given how long it has been around, you consider the Lucas A127 to be a old fashioned machine, or a modern Alternator, and whether in your view an external regulator should make any significant difference.

Edited September 17, 2009 by David Schweizer

[Proper Job]

Parallel hamsters eh!

Every one knows, you can't parallel hamsters!

 

When you bring the two universes together a black hole forms which will trip out the galvanic isolator

[Gibbo]

I have read your page, and understand what you are saying, I also recall the various "debates" which taken place over the years on exactly this subject. My experience has been that the Sterling Alternator regulator fitted to the systam on our boat does appear to reduce the charging time significantkly.

 

What I have never been able to establish is whether, given how long it has been around, you consider the Lucas A127 to be a old fashioned machine, or a modern Alternator, and whether in your view an external regulator should make any significant difference.

 

The A127 has indeed been around a very long time but the regulators are avilable in various voltages. I've seen just about everything from 13.8 to 14.8 volts so it's not really possible to say.

 

If you buy a new one, today, they usually come with a higher voltage reg on them. At least the ones I've bought have. No doubt they are still available with lower voltages from the factory.

 

Here's one way of looking at it:-

 

The laws of physics mean that, with a charging system, we can dictate the charge current from the alternator or the charge voltage. Only one or the other. We cannot control both at the same time.

 

If we set the charge current, then the voltage on the batteries will be whatever it will be - that is dictated by the batteries.

 

If we dictate the voltage from the alternator, then the charge current will be whatever it will be - that, again, is dictated by the batteries. We can only control one of them.

 

So if we get an alternator that charges at 14.6 volts, how can an external controller that regulates the alternator at 14.6 volts be any better?

 

I'll give you a hint................................

 

It can't.

 

If you really saw an improvement in charging (and I'm not saying you didn't) by fitting your controller then one of the following must apply.

 

1. The alternator was regulating at too low a voltage

 

or

 

2. You had losses in the cabling which the external controller is compensating for.

 

There is no magic in external controllers. All they do is up the voltage. Nothing more, nothing less, nothing clever.

 

Gibbo

[WotEver]

When you bring the two universes together a black hole forms which will trip out the galvanic isolator

 

And allow the magic blue smoke to escape...

[David Schweizer]

The A127 has indeed been around a very long time but the regulators are avilable in various voltages. I've seen just about everything from 13.8 to 14.8 volts so it's not really possible to say.

 

If you buy a new one, today, they usually come with a higher voltage reg on them. At least the ones I've bought have. No doubt they are still available with lower voltages from the factory.

 

Here's one way of looking at it:-

 

The laws of physics mean that, with a charging system, we can dictate the charge current from the alternator or the charge voltage. Only one or the other. We cannot control both at the same time.

 

If we set the charge current, then the voltage on the batteries will be whatever it will be - that is dictated by the batteries.

 

If we dictate the voltage from the alternator, then the charge current will be whatever it will be - that, again, is dictated by the batteries. We can only control one of them.

 

So if we get an alternator that charges at 14.6 volts, how can an external controller that regulates the alternator at 14.6 volts be any better?

 

I'll give you a hint................................

 

It can't.

 

If you really saw an improvement in charging (and I'm not saying you didn't) by fitting your controller then one of the following must apply.

 

1. The alternator was regulating at too low a voltage

 

or

 

2. You had losses in the cabling which the external controller is compensating for.

 

There is no magic in external controllers. All they do is up the voltage. Nothing more, nothing less, nothing clever.

 

Gibbo

Right, I understand that, and as I have changed the Alternator once and the regulator twice (remember my "not charging problem thread?) I guess there is no way of actually telling without disconnecting the alterrnator and testing the voltage, or would disconnecting the field wire do that?

 

The other thing which I have never fully understood is if the ammeter was showing a highest charge of 12amps without the controller, but showing 55 amps with it, does that actually mean that more is going into the battey or not?

 

My limited knowledge of electrical theory suggests that Votls measure the pressure or force of electricity, whilst Amps measure the current or the amount of electric charge, but diffentiating between the two still cause me confusion when talking about charging batteries.

 

I realise that this is basic stuff for an electroniocs person but any explanation would be helpful.

Edited September 17, 2009 by David Schweizer

[MoominPapa]

And allow the magic blue smoke to escape...

It's OK, I've got some spare......

 

 

MP.

[Gibbo]

Right, I understand that, and as I have changed the Alternator once and the regulator twice (remember my "not charging problem thread?) I guess there is no way of actually telling without disconnecting the alterrnator and testing the voltage, or would disconnecting the field wire do that?

 

Yes. Disconnect the field wire, keep charging but give the batteries 10 minutes or so to settle to the alternator voltage then measure it.

 

The other thing which I have never fully understood is if the ammeter was showing a highest charge of 12amps without the controller, but showing 55 amps with it, does that actually mean that more is going into the battey or not?

 

Usually yes, but it depends upon the voltages. If the alternator alone charges at (say) 13.8 volts and the reg at 14.6 volts then yes it would almost all be increased charge current.

 

But if the alternator alone already charges around (say) 14.4 volts, and the controller runs at 14.8 volts then a good portion of the increase in measured current will actually just be electrolysing water as opposed to charging the batteries up. How much is very difficult to even have a guess at because there are so many variable.

 

This subject kept coming up a while ago because a mathematician couldn't accept that the measured current into a battery doesn't all charge it up.

 

My limited knowledge of electrical theory suggests that Votls measure the pressure or force of electricity, whilst Amps measure the current or the amount of electric charge, but diffentiating between the two still cause me confusion when talking about charging batteries.

 

I realise that this is basic stuff for an electroniocs person but any explanation would be helpful.

 

Voltage = water pressure.

Current = volume of water moving.

Resistance = inverse of the water pipe diameter.

Power = water pressure multiplied by the volume of water moving.

 

Think of a pipe at the bottom of a dam.

 

Gibbo

[David Schweizer]

Yes. Disconnect the field wire, keep charging but give the batteries 10 minutes or so to settle to the alternator voltage then measure it.

 

 

 

Usually yes, but it depends upon the voltages. If the alternator alone charges at (say) 13.8 volts and the reg at 14.6 volts then yes it would almost all be increased charge current.

 

But if the alternator alone already charges around (say) 14.4 volts, and the controller runs at 14.8 volts then a good portion of the increase in measured current will actually just be electrolysing water as opposed to charging the batteries up. How much is very difficult to even have a guess at because there are so many variable.

 

This subject kept coming up a while ago because a mathematician couldn't accept that the measured current into a battery doesn't all charge it up.

 

 

 

Voltage = water pressure.

Current = volume of water moving.

Resistance = inverse of the water pipe diameter.

Power = water pressure multiplied by the volume of water moving.

 

Think of a pipe at the bottom of a dam.

 

Gibbo

Thanks. We are planning to spend a few days on the boat this weekend, so I will try out your suggestions.

[blackrose]

This subject kept coming up a while ago because a mathematician couldn't accept that the measured current into a battery doesn't all charge it up.

 

I thought the subject kept coming up because he had good results with an external regulator!

Edited September 17, 2009 by blackrose

[Gibbo]

I thought the subject kept coming up because he had good results with an external regulator!

 

No it kept coming up because he thought (thinks) the measured current into a battery is what charges it up without realising that some of the current does other things

 

Gibbo

[Sir Nibble]

I have read your page, and understand what you are saying, I also recall the various "debates" which taken place over the years on exactly this subject. My experience has been that the Sterling Alternator regulator fitted to the systam on our boat does appear to reduce the charging time significantkly.

 

What I have never been able to establish is whether, given how long it has been around, you consider the Lucas A127 to be a old fashioned machine, or a modern Alternator, and whether in your view an external regulator should make any significant difference.

An A127 is a comparatively modern machine sensed alternator.

Let be explain what this machine sensed / battery sensed thing is about.

 

Battery sensed is where the regulator samples the voltage at the battery and controls accordingly.

 

Machine sensing. The alternator has two outputs, B+ which is the output to the battery and D+ which is an output from 3 auxiliary diodes to power the field coil. A machine sensed alternator samples the voltage at D+ which in theory should be the same as at B+ but in fact rarely is. This is shall we say a subject for discussion, but my personal opinion is that the difference between B+ and D+ makes the machine sensed alternator far less suitable for battery charging.

 

The latest generation (no pun intended) of alternators samples voltage at the B+ terminal which will differ from the actual battery voltage only by the volt drop of the cables. This is a much more suitable machine for battery charging.

In short, on the one occasion I have had charging problems on an A127 equipped boat I found a considerable improvement from fitting a seperate battery sensing regulator.

[David Schweizer]

An A127 is a comparatively modern machine sensed alternator.

Let be explain what this machine sensed / battery sensed thing is about.

 

Battery sensed is where the regulator samples the voltage at the battery and controls accordingly.

 

Machine sensing. The alternator has two outputs, B+ which is the output to the battery and D+ which is an output from 3 auxiliary diodes to power the field coil. A machine sensed alternator samples the voltage at D+ which in theory should be the same as at B+ but in fact rarely is. This is shall we say a subject for discussion, but my personal opinion is that the difference between B+ and D+ makes the machine sensed alternator far less suitable for battery charging.

 

The latest generation (no pun intended) of alternators samples voltage at the B+ terminal which will differ from the actual battery voltage only by the volt drop of the cables. This is a much more suitable machine for battery charging.

In short, on the one occasion I have had charging problems on an A127 equipped boat I found a considerable improvement from fitting a seperate battery sensing regulator.

OK, if I need one, where do I get one from? All the regulators in my spares box have a field wire soldered to them, If I connect that to the Battey, does that make the alternator battery sensing, or will it blow something up?

[Arnot]

Hi,

 

I have searched on this topic so apologies if I've missed an answer in the haystack.

 

I was recently told that running the engine to charge the batteries may not fully charge them, and that special chargers exist which find exactly the right voltage to get them to 100% more efficiently. I suspect there may be a combination of truth and simplification in this..!

 

I have identified various mains chargers which appear to fit this description, but:

 

My question: if I am not charging from mains (I have no shore power) but only via the engine, does a charger exist which would fit between my alternators and the batteries to do the same thing? I.e. is there a better set-up than just alternators alone for charging from the engine?

 

Thanks for any suggestions

 

Matthew

I suggest an application of the new nanopower fluid from “Serpentoleum”. It is a carefully formulated of graphene and Buckminster Fullerine nanotubes suspended in a superfluid binder that also serves as a transmission medium.

 

To use is carefully invert the applicator and direct an atomised fan of the fluid into the back of the alternator while the engine is running at idle speed.

 

Once the binder has stabilised and cured, the highly conductive nanotubes will create a conformal coating surrounding the powerful wiring in the alternators core. The effect of the nanotubes is to direct and focus the fluctuating lines of magnetic force so that they totally surround the individual generation conductors. At the same time, the tubular nature of the nanotubes will both filter and redirect the cooling air blast to the hottest points of the interior of the core.

 

Application of “Serpentoleum” will convert your standard alternator to a piece of space age powerhouse battery charging equipment. According to Ms. C Stunt (VP Marketing), “Serpentoleum” is the major advance in rotating electrical machinery for the 21st Century and can make almost any standard piece of equipment into a piece of “Super High Intelligent Transponder” machinery.

 

I Hipe this hleps

 

 

Arnot

 

OK, if I need one, where do I get one from? All the regulators in my spares box have a field wire soldered to them, If I connect that to the Battey, does that make the alternator battery sensing, or will it blow something up?

For an A127 you will need to get hold of this regulator which can be ordered from any good auto electrical specialist. It is intended for fitment to tractors and has an orange lead which senses a thermistor to lower the voltage when the batteries are getting hot.

 

If you insert a resistor of about 220 to 240 ohms instead of the thermistor and connect the other end to the battery positive, you get battery sensing for about £20 including all parts. If you take the orange wire up to the control area and instead fo the fixed resistor, use a 100 ohm pot in series with a 180 ohm resistor, you have a variable regulator for your alternator, this time for about £30.

 

Simples...

 

Regards

 

Arnot

[Arnot]

My question: if I am not charging from mains (I have no shore power) but only via the engine, does a charger exist which would fit between my alternators and the batteries to do the same thing? I.e. is there a better set-up than just alternators alone for charging from the engine?

I did post a rather tongue in cheek response last night and having read it this morning realise that it may have been a bit glib - sorry!

 

To answer your query more constructively, the principal of charging the batteries from an engine driven alternator is a good one and cannot really be improved on.

 

However the vast majority of alternators fitted to boats were intended for running the electrical system of a vehicle of some description, for them to charge a battery optimally they need to have a different control system i.e. battery sensed. some modern alternators have this facility internally as standard but it does have to be wired up correctly to be of benefit.

 

Alternatively there are a number of external regulation system offered with verying degrees of hype and price tickets. Most do the job perfectly well.

 

Regards

 

Arnot

[Gibbo]

OK, if I need one, where do I get one from? All the regulators in my spares box have a field wire soldered to them, If I connect that to the Battey, does that make the alternator battery sensing,

 

No.

 

or will it blow something up?

 

Yes. The regulator.

 

Gibbo