High Rated Alternator with Alternator to Battery Charger

[goboatingnow]

Originally Posted by sailinglegend

You are so right to discourage this....



The Sterling is a clever BODGE for alternators that would otherwise have to be taken apart and modified to be able to control the field wires. But in doing this it will suck out all the power it can and then provide a higher voltage to charge the batteries. This will over stress and over heat the maybe already OLD alternator whose overall power output would then be much reduced and it may well fail earlier than it should.



So if you have an alternator with Field wires accessible then please use a proper external regulator, not a Sterling A2B 'regulator'.

This is not good advice. The newer sterling unit is in effect a high powered DC to DC convertor , leaving aside efficiency losses there is no downside to what it does and it stresses an alternator no less or no more then any high power regulator.

It's certainly not a " Bodge " it's quite an innovative product. A market first I believe

As to " suck out all the power it can " , it will draw whatever power the batteries can accept. Just like any smart regulator

Dave


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[sailinglegend]

Originally Posted by goboatingnow

This is not good advice.....

Then I think you need to read FULLY Mr Sterling's instructions.

First he says it is to replace a 'standard alternator regulator' - these are the sort on a standard cheap automotive alternator. EDIT: The OP was going to use a Balmar alternator which has an external field wire for an external regulator.

Originally Posted by goboatingnow

...It's certainly not a " Bodge " it's quite an innovative product. A market first I believe....

Yes I agree it's quite clever, but read his explanation of what actually happens which is carefully not included in the latest product information.... Clever marketing, because he has had a lot of comments of how he achieves this DC to DC amplification.

Originally Posted by goboatingnow

...As to " suck out all the power it can " , it will draw whatever power the batteries can accept...

This is his description of what actually happens:

In order to maximise the alternator output current, the alternator-to battery charger pulls the alternator output voltage down to about 13V. Then this low voltage is amplified to a higher voltage suitable for effective battery charging, i.e. 14.1V to 14.8V. The unit’s intelligent software automatically calculates the optimum charge cycle and absorption time. When the batteries have been fully charged the voltage is reduced to float voltage (appr. 13.5V to 13.8V).

So he gets a low voltage by applying a high current load, and then uses this 'power' and amplifies the voltage for as long as the unit is charging at 14.8 volts, and probably even when in Float because the voltage he has dragged the alternator down to is always lower than Float. This would seem to be a very very inefficient process compared to fitting a normal external regulator where the field current is reduced as the battery accepts less charge current.

So it would seem that for a majority, if not all, of the charge cycle the poor old standard automotive alternator is being heavily loaded and being asked to do something it was not designed to do - and that was simply to charge very quickly a starter motor that had maybe 1% of it's capacity removed. A deep cycle bank with 50% of its capacity removed is going to heavily load a 'standard alternator' without Mr Sterling's clever 'bodge' adding to the load.

[Timd_chapman]

I have had an A2B fitted for the last 3 years. It works very well doing exactly what it was designed to do. My reasoning for fitting this against fitting an after market regulator is that is is very easy to fit any spare/replacement alternator without having to fit a field sensing wire to the alternator.
As a full time long distance sailor I guess my alternators work just as hard as anyone's and have never overheated, but then the A2B has a alternator temperature sensing cable so the A2B will back the load off if everything starts getting too warm.
So in answer to the OP I can fully recommend that you fit one.


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[d4raffy]

hmmm .. in the interest of healthy debate ... how many of these cheap stock alternators are really actually failing ? ..

My reasoning being ... that as one travels to far-off reaches of the planet any old alternator can be utilised (or carried as spare) and the A2B will always get the best from it .... Without any modification to the alternator internals or being tied to a specific vendor compatible product .... ??

[colemj]

Originally Posted by sailinglegend

So it would seem that for a majority, if not all, of the charge cycle the poor old standard automotive alternator is being heavily loaded and being asked to do something it was not designed to do - and that was simply to charge very quickly a starter motor that had maybe 1% of it's capacity removed. A deep cycle bank with 50% of its capacity removed is going to heavily load a 'standard alternator' without Mr Sterling's clever 'bodge' adding to the load.

This is no different than if an external regulator was fitted to a standard alternator. Since the device does not directly control a field wire, it simply does a DC-DC conversion to pull the voltage down on the alternator output to cause its internal regulator to keep high voltage on the field wire.

An external regulator would just supply that field wire voltage itself instead of "asking" the internal regulator to supply it - as the Sterling device does.

In both cases, the alternator is driven exactly equally with the same output.

In both cases, a standard alternator can be driven harder than it was designed for. The Sterling device contains an alternator temperature sensor that protects the alternator from being driven too hard.

If your argument is that one needs to be careful when driving a standard alternator beyond the internal regulator settings, then I agree.

If your argument is that this Sterling device is a "bodge" or somehow over-driving an alternator any differently than an external regulator would, then you are wrong.

Mark

[colemj]

Originally Posted by d4raffy

hmmm .. in the interest of healthy debate ... how many of these cheap stock alternators are really actually failing ? ..

My reasoning being ... that as one travels to far-off reaches of the planet any old alternator can be utilised (or carried as spare) and the A2B will always get the best from it .... Without any modification to the alternator internals or being tied to a specific vendor compatible product .... ??

We have a modified stock 60A Valeo alternator to which I have added an external field wire. Without a temperature sensor on it to cut the field back when hot, the alternator will reach 250-270F (I have measured this - I also use a temperature sensor on it in normal use).

So while I don't know the answer to your question, I can guess that without some mode of protection like the A2B provides with a temperature sensor, these alternators could be burned out pretty quickly.

Mark

[DeepFrz]

Does anyone know at what temp. the A2B cuts back? I understand that standard stock auto type alternators already have thermal cutback so I can't see that the A2B can do anything more than a modern regulator in a stock alternator. Personally I think its snake oil. If its not burning out alternators then it isn't producing more than the alternator will produce with the stock regulator. I would be happy to be wrong about this but I don't believe I am. The A2B doesn't produce power, it just manipulates what the alternator produces. One would probably be better served by just adding a fan to blow cool air on the stock alternator with an internal regulator.

[colemj]

Originally Posted by DeepFrz

Does anyone know at what temp. the A2B cuts back? I understand that standard stock auto type alternators already have thermal cutback so I can't see that the A2B can do anything more than a modern regulator in a stock alternator. Personally I think its snake oil. If its not burning out alternators then it isn't producing more than the alternator will produce with the stock regulator. I would be happy to be wrong about this but I don't believe I am. The A2B doesn't produce power, it just manipulates what the alternator produces. One would probably be better served by just adding a fan to blow cool air on the stock alternator with an internal regulator.

I believe the cutback is 90C, but I do not know that for certain.

The problem with an internal regulator is that it does not drive the charge voltage high enough and cuts the current back too soon.

This device isn't snake oil or manipulation anymore than an external regulator is - they both do exactly the same thing, only achieving it in slightly different ways. The external regulator directly controls the field on the alternator through voltage on the field wire, while the A2B indirectly controls it by asking the existing regulator to please put more voltage on the field wire.

A stock alternator can easily produce more output than its internal regulator will allow, and can do so without burning out.

Adding a fan to an internally regulated alternator typically won't help output much because that is cut back more often due to reaching the voltage set point than to temperature.

Mark

[goboatingnow]

Thanks , I see my view been vindicated. , otherwise we are descending into voodoo electronics again.

All the A2B does is DC DC conversion. It no more loads the alternator then the battery can take by stepping up the voltage it extracts more " potential " power from the alternator then the conventional automotive regulator, which is not primarily designed to charge batteries, but to supply constant voltage to the cars electrical systems

Dave


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[MechMan]

I have had a Sterling A2b coming up four years on a Yanmar with an 80amp alternator. I has a temp sensor on the alternator which switches to a low mode at 90 degrees, then on again at 80 degrees. It doesn't get that hot now I've directed the inflow air pipe onto the back of the alternator.

I would do the same again. Although it seems a complicated way to boost power, it's simple to install and this system does give redundancy if the sterling fails.

To the guy who was wondering about going to a different alternator. I went from a 60 amp to an 80 amp. I think the 80 amp has more poles and the tachometer did read faster. I bought a hand held tachometer off ebay and calibrated the yanmar unit by adjusting a screw on the back. Igor the warning that says not to tamper with it.

[Ex-Calif]

Interesting discussion. I am all for driving equipment to their nominal ratings as long as possible. I am also all for keeping equipment as cool as possible.

For those who haven't internalized what this thing does I suggest reading at least page 5 of the attached link.

http://www.sterling-power.com/images...%20Control.pdf

The real key for me is the Domestic Battery voltage curve and the Domestic battery current curve. Most on this thread understand this but in a "normal" system as battery voltage increases field voltage is reduced and alternator output drops. Keeping alternator output up is probably a good thing.

I am not convinced that this thing "overdrives" an 80 amp alternator to magically produce 100 amps. It seems to just make that alternator produce 80 amps longer. And if that results in a tougher duty cycle, there is really no free lunch anyway.

Oh, well - fascinating discussion.

[colemj]

Originally Posted by Ex-Calif

I am not convinced that this thing "overdrives" an 80 amp alternator to magically produce 100 amps. It seems to just make that alternator produce 80 amps longer. And if that results in a tougher duty cycle, there is really no free lunch anyway.

Yes, that is correct - it doesn't magically produce more instantaneous current than the alternator's rating. It just makes the alternator produce that current for a longer time and to a higher voltage in doing so - the exact same as an external regulator does, although they employ slightly different methods to achieve this.

The only thing to be careful of is that many small OEM alternators do not have the heat sinks, fans, speed and diode ruggedness as true HO alternators do. Driving them at higher current for long times can heat them quite dramatically and cause failure. The Sterling unit uses a temperature sensor to protect against that.

This is also true for an external regulator added to an OEM alternator.

Mark

[Maine Sail]

Guys,

Please be aware that the Sterling A2B will have a "float voltage" of no lower than the internal regulators original setting. The A2B's boost voltage but float is what you always had...

[d4raffy]

Originally Posted by Maine Sail

Guys,

Please be aware that the Sterling A2B will have a "float voltage" of no lower than the internal regulators original setting. The A2B's boost voltage but float is what you always had...

Hi Maine ... are you saying this is an issue ??

Quote from my A2B docs -- >
"The unit’s intelligent software automatically calculates the optimum charge cycle and absorption time. When the batteries have been fully charged, the voltage is reduced to float voltage (appr. 13.5V to 13.8V)."

I was hoping this was dependant on the Battery type setting you had selected and would be appropriate ?

Not that I have ever seen my current reg go into Float when I engine on voyage. Maybe thats a SV thing not a MV thing ?

To the guy who was wondering about going to a different alternator. I went from a 60 amp to an 80 amp. I think the 80 amp has more poles and the tachometer did read faster. I bought a hand held tachometer off ebay and calibrated the yanmar unit by adjusting a screw on the back. Igor the warning that says not to tamper with it.

Thanks for the tip on the ebay tacho (purchase on the way) ... where do you (stick the reflective tape) to measure the rotation to find the RPM ?? - water pump pulley ?? And the adjustment screw is on the back of the Tacho meter on the engine control panel ?

[colemj]

Originally Posted by d4raffy

where do you (stick the reflective tape) to measure the rotation to find the RPM ?? - water pump pulley ??

Put it directly on the crankshaft pulley - it needs to measure the engine rpm without any speed changes due to pulley differentials like on most water pump and alternator pulleys.

Mark