High Rated Alternator with Alternator to Battery Charger

[alamoana]

I sugestiono a Leece Neville alternator approx 100 Amps to 130 Amps with a regulator that fan thheottle it down so your un It at 80 Amps Max, such as Amplepower SARV3. There are many options and combinations some cheaper some more expensive. This has worked for me with a small engine 29 HP and 550 AH FLA bank for 13 years


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[DeepFrz]

That is pretty much what Maine Sail advises.

[sailinglegend]

Originally Posted by Ex-Calif

....The internally regulated alternator will give its full output until the voltage comes up on the bank.

That is pretty much correct but doesn't tell the whole story.

The auto regulator is a 'constant voltage' regulator which tries to output it's rated voltage, say 14.2v, and delivers the maximum current which falls away exponentially as the battery acceptance rate falls. Yes there will be a reduction in the actually voltage it can achieve because of temperature compensation. Some regulators might cut the output current down when too hot, modern ones reduce it as the temperature rises because the batteries need a lower charging voltage when hotter because they start to gas at a lower temp. The problem is the batteries should be nowhere near the alternator on a boat so this temperature compensation is a real inefficient waste of energy.

An external multi-stage charger starts as a 'constant current' charger to deliver a high current up to the point the batteries reach the absorption voltage, 14.4v, at which point the batteries are 80-85% charged, and then the charger limits the voltage rise to become a 'constant voltage' charger for a 'timed' period when it drops to float to protect the battery from overcharge. This is a faster charging profile than the internal regulato.

To make it more efficient it will also have an external battery sense wire and battery and alternator temperature compensation.

Originally Posted by Ex-Calif

"hot rated" is an undefined term for me. Higher rated makes sense. Is that what you mean?...

Auto regulators may have a 'cold' rated current output and a 'hot' rated one, but you may find it very difficult to get that info from the manufacturers!!!

One final thought a 100 amp alternator will put a 4 HP load on the engine, and a large case bus type alternator may be too large to fit in the space, and need new expensive mounting brackets. Balmar do small case high output alternators that should directly replace the existing auto alternator.

[d4raffy]

Originally Posted by goboatingnow

Should be was replaced on a RR for about 550 pounds all in

RR Reliant Robin ? lol

[d4raffy]

Originally Posted by alamoana

I sugestiono a Leece Neville alternator approx 100 Amps to 130 Amps

I did have a quick look / search in this area but the problem seems to be there is not an exact 'drop-in' for the Yanmar alternator mounting configuration / bracket. So i guess you would have to revert to a custom job. Unless anyone knows otherwise ?

[goboatingnow]

Originally Posted by d4raffy

RR Reliant Robin ? lol

absolutly, its obvious why it needs a water cooled 150 A alternator

dave

[goboatingnow]

The auto regulator is a 'constant voltage' regulator which tries to output it's rated voltage, say 14.2v, and delivers the maximum current which falls away exponentially as the battery acceptance rate falls. Yes there will be a reduction in the actually voltage it can achieve because of temperature compensation. Some regulators might cut the output current down when too hot, modern ones reduce it as the temperature rises because the batteries need a lower charging voltage when hotter because they start to gas at a lower temp. The problem is the batteries should be nowhere near the alternator on a boat so this temperature compensation is a real inefficient waste of energy.

An external multi-stage charger starts as a 'constant current' charger to deliver a high current up to the point the batteries reach the absorption voltage, 14.4v, at which point the batteries are 80-85% charged, and then the charger limits the voltage rise to become a 'constant voltage' charger for a 'timed' period when it drops to float to protect the battery from overcharge. This is a faster charging profile than the internal regulato.

This text illustrates the confusion that arrises when people talk about battery charging and regulation, In practice both the internal regulator and external regulator will behave identically under full load.

Alternators typically cannot remain "in regulation" under high loads typical of bulk mode charging, The determining factor is the battery terminal voltage. Hence irrespective of regulator type , the regulator/alternator is in "constant current " mode ( or course its no such thing as constant current actually ) .

In this mode "regulation" is more concerned with system monitoring( i.e. various temps) typically with foldback current control when things get out of hand.( some regulators do partial switch off. )

The primary difference between a automative "style" regulator is it is not optimised for absorption mode charging, i.e., typically it regulates out at about 13.8-14v. ( there has been a tendency to raise the regulation voltage in recent years). This is because the primary role of a car regulator is to act as a system power supply.

A regulator ( internal external or other wise) more optimised for battery charging, MAY, have its absorption point higher then a typical car regulator, allowing the bulk mode to finish quicker and to provide as fast as possible absorption phase.

IN effect all alternators regulators have a constant current , constant voltage profile, even if the "constant current" actually isn't in regulation at all.


dave

[sailinglegend]

Originally Posted by goboatingnow

This text illustrates the confusion that arrises when people talk about battery charging and regulation, In practice both the internal regulator and external regulator will behave identically under full load.

That is a totally unfair criticism of my posting and not correct.

The distinction between constant current charging and constant voltage charging is industry standard, even though the constant voltage output on an auto internal regulator is nothing but constant. As I said it 'tries to reach its rated voltage.' The voltage output of each will be similar, but not the current.

Even Mr Sterling in his A2B link above shows the difference between the exponential fall in the charging current fron a constant voltage charger and the constant current charge output with his A2B charger fitted.

Trying to be pedantic and clever is just not - clever!

[d4raffy]

Originally Posted by goboatingnow

absolutly, its obvious why it needs a water cooled 150 A alternator

Sorry for the Humour injection - Could be a 'Del Boy' Special

[colemj]

Originally Posted by sailinglegend

That is a totally unfair criticism of my posting and not correct.

The distinction between constant current charging and constant voltage charging is industry standard, even though the constant voltage output on an auto internal regulator is nothing but constant. As I said it 'tries to reach its rated voltage.' The voltage output of each will be similar, but not the current.

Even Mr Sterling in his A2B link above shows the difference between the exponential fall in the charging current fron a constant voltage charger and the constant current charge output with his A2B charger fitted.

Trying to be pedantic and clever is just not - clever!

Dave was not being either pedantic or clever - just factual.

For any regulator - internal or external, there is no constant voltage regulation when the battery voltage is below their setpoint. The regulator simply allows the alternator to pump out the maximum amount of current it can until the voltage of the battery rises to that of the regulator's setpoint. This is the mode you are calling "constant current", which is a practically correct term.

At this time, both internal and external alternators start to limit that current to maintain the voltage of their setpoint. This is the mode you are calling "constant voltage", which again is a practically correct term.

So up to this point, both internal and external regulators work exactly the same way, with both operating in regions of constant current and constant voltage. There is absolutely no operating difference between them throughout what is commonly referred to as bulk and absorption regimes.

The difference between the two occur when the external regulator can drop the voltage to a lower level after the batteries are fully charged. In practice, this isn't even a very big difference, since most of them drop to a voltage that the internal regulator is already in. It does become a larger advantage when the batteries being charged require a particular charge profile not common on an internal regulator.

And, of course, internal regulators generally have lower voltage setpoints than external, which means that they start to limit their current output sooner than external regulators. This is the point where the Sterling A2B steps in and makes a difference.

However, if the external and internal regulators have the same voltage setpoint, they will behave exactly the same way all the way to the point of the battery being fully charged - at which point the external regulator will drop the voltage, while the internal will not.

Mark

[sailinglegend]

Originally Posted by colemj

Dave was not being either pedantic or clever - just factual.....

You are both being factually incorrect and showing your ignorance. This is spoiling a thread that a lot of people are following.

It is impossible in a posting like this to fully explain exactly what is happening, so people need to refer to other material, and I suggest they check out Nigel Calder - and I add graphs where he compares Constant Voltage and Constant Current charging and clearly shows the difference which occurs, especially during Boost Mode. This concurs exactly with my postings.

------------------------
Ignorance isn't what you don't know, it's what you think you know that is incorrect.

[colemj]

While Calder does use those terms to differentiate between standard internal alternators and the new fangled multistage external regulators that were just coming on the market in the early-90's (you are reading a very old book), he does not describe their operation like you think or says he does. You have mis-comprehended his writing.

The only reason he uses those terms is to differentiate between multistage regulators that have higher bulk/absorption voltages with the ability to change that voltage, as compared to fixed voltage regulators that only charge up to a single voltage and stay there forever.

Again, at the time of his writing, these external regulator thingies were brand-spanking new and nobody understood anything about them.

Both operate as current devices when the battery voltage is below their setpoints. The reason external regulators put more current into a battery in the beginning is that they are regulated up to a full volt higher than internal ones, so they see little resistance to current from the battery until the battery voltage rises fairly high.

If you step your reading up a decade or so, you will find that Calder's description nowadays is both confusing and ancient.

I have both types of alternators on board and can switch them into internal/external regulation at will. I promise you that the internal regulators let the alternator provide full current during the initial charging, and throttle that back only when the battery voltage gets above 13.5V or so. The external regulators do the same, only they allow the alternator to go full current to 14.4V or so before cutting it back.

That is what Calder is saying, and his graphs support that fully - just look at where the internal and external curves meet when the external goes into absorption mode, and look where each ends up at full charge.

Mark

[goboatingnow]

Originally Posted by sailinglegend

You are both being factually incorrect and showing your ignorance. This is spoiling a thread that a lot of people are following.

It is impossible in a posting like this to fully explain exactly what is happening, so people need to refer to other material, and I suggest they check out Nigel Calder - and I add graphs where he compares Constant Voltage and Constant Current charging and clearly shows the difference which occurs, especially during Boost Mode. This concurs exactly with my postings.

------------------------
Ignorance isn't what you don't know, it's what you think you know that is incorrect.

I can't been begin to tell you how parts of that Calder diagram are incorrect or just plain silly.

If you'd like to find me a "constant current " anything , that can maintain say a constant current into a 1000 Ah battery bank , I'd love to see it. Those curves don't actually exist in real life and are very misleading.

The terminal voltage of a charging battery is shown in the graph below, these are real graphs. You can see that varying the charge current doesn't radically alter the curve shape.

Mr Calders " constant current" graph is absolute fiction, ( edit /fundamentally misleading )

fundamentally the terminal voltage is set by the battery, current that flows is a function of acceptance. There is fundamentally no difference as to how an "internal " regulator and a external regulator deal with bulk charging, up to as was pointed out the voltage set point

dave

[sailinglegend]

Originally Posted by colemj

While Calder does use those terms to differentiate between standard internal alternators and the new fangled multistage external regulators that were just coming on the market in the early-90's (you are reading a very old book), he does not describe their operation like you think or says he does. You have mis-comprehended his writing.

Again you are showing your ignorance. The graphs I attached were from his LATEST book - yes it is 2005 - but he is describing modern Balmar Type external regulators. I have the 1996 version too which is very different.

You are always telling people they have mis-comprehended other's writings. You always know better - now even Nigel Calder is wrong!

[colemj]

Actually, let me try this another way.

Do you agree that the only way to control the output of an alternator is to control the current on the field wire? Regardless of whether it is an internal or external regulator?

If so, then please describe how this one single point of control of an alternator's output is different between what you call a "constant voltage" regulator and a "constant current" regulator.

I don't see how it can be different, but am willing to learn something new.

Mark