High Rated Alternator with Alternator to Battery Charger

[sailinglegend]

Originally Posted by Ex-Calif

....Your assumption that the automotive alternator works for 5 minutes and then is off duty is flawed. Modern cars have pretty greedy ....

Why can't people read and understand posts properly. They tend to read what they think supports their argument.

I said an automotive alternator will be unable to deliver its full output when being asked to charge a 50% depleted 400ah bank. I didn't say it would stop working or burn out! Yours may only give 35 amps output, but with only a 210Ah bank you may well be fine. Any bigger and a hot rated alternator will charge faster - that's what most people want.

BUT no automotive alternator is going to give this charge into the batteries, hot or cold, unless it has an external regulator. As Mr Sterling says, if your alternator is 13.8 volts then a multi stage regulator can charge 5 times faster. He is right. Even more modern 14.2v regulators will do better, but then their temperature compensation starts to reduce the voltage output because it assumes the batteries are near the engine. Hotter batteries need a lower charging voltage. So you may be down to 14v fairly soon. This will power all the car loads but it won't charge batteries properly. Most batteries need at least 14.4 volts to start very slight gassing which stirs up the electrolyte.

So an automotive alternator for a small house bank may be fine, but if budget is an issue get an external regulator before upgrading the alternator.

[Ex-Calif]

Originally Posted by sailinglegend

Why can't people read and understand posts properly. They tend to read what they think supports their argument.

Having made my living as a "technical interpreter" for 30 years I can attest the majority of the communication responsibility rests with the sender. No need to get frustrated.

Actually I think we are closer in agreement than we may think.

Originally Posted by sailinglegend

I said an automotive alternator will be unable to deliver its full output when being asked to charge a 50% depleted 400ah bank.

The internally regulated alternator will give its full output until the voltage comes up on the bank. A 60amp alternator is woefully inadequate for bulk charging this bank.

(Of course there are other factors such as battery temperature that impact acceptance rates)

Originally Posted by sailinglegend

I didn't say it would stop working or burn out! Yours may only give 35 amps output, but with only a 210Ah bank you may well be fine.

You did elude to the unreliability of an automotive alternator but maybe I misunderstood.

Originally Posted by sailinglegend

Any bigger and a hot rated alternator will charge faster - that's what most people want.

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

Or you mean an alternator that withstands hotter temperatures?

Originally Posted by sailinglegend

BUT no automotive alternator is going to give this charge into the batteries, hot or cold, unless it has an external regulator.

<snip>

So an automotive alternator for a small house bank may be fine, but if budget is an issue get an external regulator before upgrading the alternator.

I agree with all of this. So for the boater that wants improved performance from his "existing" system the Sterling "Magic Box" is a viable solution.

In general terms if one has increased the battery bank capacity one would want an alternator that can provide 25% of the rated A/H capacity. i.e. for a 400 a/h bank a 100 amp alternator or larger would be desired.

[DeepFrz]

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

This is not so. The internally regulated alternator will give its full output ONLY until it is cut back by the temp. sensing internal regulator or the battery voltage reaches a certain point. What often happens when charging a house bank is the alternator starts to over heat and is cut back long before the bank is charged.

[Ex-Calif]

Originally Posted by DeepFrz

This is not so. The internally regulated alternator will give its full output ONLY until it is cut back by the temp. sensing internal regulator or the battery voltage reaches a certain point. What often happens when charging a house bank is the alternator starts to over heat and is cut back long before the bank is charged.

I am not sure many stock internally regulated alternators are temperature limiting.

BTW - This is a great discussion. It is challenging many of my paradigms.

Balmar seems to be the "go to" alternator for us but the off-road guys and the overland truck guys have all kinds of ideas and arguably a bigger market for product development.

I won't bore you with cross posting performance curves but there are truck alternators out there rated at 250+ amps that operate higher output curves at lower RPM.

Delco, Nippondenso etc. all show high duty factory alternators with huge capacities.

Off-rad guys have winches and other high demands, overland truck guys have aircon, coffee pots etc and spend long hours idling in crappy winter weather at truck stops.

We might be able to learn thing or two from them.

[DeepFrz]

I agree that there are alternatives now that were not readily available a few years ago that seemingly would be suitable for cruising. I worked on a "truck" alternator on a boat that would not handle the load of charging a house bank. It was in mid nineties and I don't know what the specs were (didn't then either). Actually I don't even remember the size of the house bank but it was fairly large for the time. It was a crap setup and caused no end of trouble once we got south of berthing facilities. No solar or wind generation then. One thing it did though was get me extremely interested in cruising electrical systems.

[d4raffy]

Originally Posted by Ex-Calif

BTW - This is a great discussion. It is challenging many of my paradigms
.

I agree .. the more i research this - it seems Balmar is the way to go ... although I think i will test out my stock Hitachi first (maybe to the limits with my A2B! ).
I am also going to run some extra venting for the alternator.

I do hope the OP comes back at some point to tell us how he got on with his Balmar Alternator.

[Ex-Calif]

Originally Posted by DeepFrz

I agree that there are alternatives now that were not readily available a few years ago that seemingly would be suitable for cruising. I worked on a "truck" alternator on a boat that would not handle the load of charging a house bank. It was in mid nineties and I don't know what the specs were (didn't then either). Actually I don't even remember the size of the house bank but it was fairly large for the time. It was a crap setup and caused no end of trouble once we got south of berthing facilities. No solar or wind generation then. One thing it did though was get me extremely interested in cruising electrical systems.

I have been admonished a couple times around here for not reading Calder's book. Well, I do have it and I did crack it open the other night.

While the basic theory is sound, and AFAIK no one has changed any physics laws recently, the equipment and technology is woefully out of date. Also his "sailboat" equipment list isn't quite as comprehensive as I am seeing lately.

I think you gotta stay plugged in, accept that the day you buy stuff there is a new mousetrap available and hope the stuff you buy lasts 5-10 years.

It's weird how these conversations go and what seems obvious to one is incomprehensible to others.

We take our gadgets to sea - it's a modern day fact. What I find "amusing" is how many folks buy a 30 foot boat and the first thing they want is $5k worth of nav gear. I have a friend here like that. He's staring at the plotter trying to enter waypoints and I can see the lighthouse!

The auto industry has adapted and many (most) full size cars have +100amp alternators.

The boat world still ships 60amp alternators and sub 200a/h battery systems, with little design consideration on where a buyer might stick more batteries.

I understand but am amazed at folks putting in >1000a/h banks but not really considering consumption and the supply side of the equation.

[colemj]

Originally Posted by Ex-Calif

The boat world still ships 60amp alternators and sub 200a/h battery systems, with little design consideration on where a buyer might stick more batteries.

All small Volvo diesels have come standard with 115A alternators since 2008.

Mark

[goboatingnow]

High performance alternators are just that, whether they be automotive, truck or marine. IN modern cars alternators are high output, BMWs larger cars are fitted with a water cooled, 90-150A alternator as standard.

To suggest that "automative" is port quality is to speak out ones behind. Internal regulars are quite sophisticated systems, integrating temperature and load dumping protection , soft start etc.

Utilising an internal regulator and a sterling A2B is merely one way of extracting the alternator output in a manner more suitable to battery charging . It is NOT appreciated by the masses that the primary purpose of the modern alternator is to supply the cars electrical system, NOT to charge the battery. Hence its regulator profile is more suitable to constant voltage PSU type operation.

Sterlings A2B was primarily designed to allow a standard internal regulator to be converted into a better battery charger without needing to replace the internal regulator. Its a clever and sophisticated piece of electronics, that few have bothered to replicate as designing relaible and robust high powered DC-DC convertors is not an easy task.

To say such a method "overloads" or overly stresses the alternator is nonsense. During bulk mode, the alternator will merely output as much as its regulator will allow. As the DCDC unit steps up the voltage to absorption levels, it will suck out more power then a normal regulator would deliver at elevated voltages, but again within the regulators parameters.

This is identical to what a balmar regulator would also do. its merely an external regulator whose profile has been modified or customised to suit 3 stage battery charging as opposed to power generation.


dave

[FlyingCloud1937]

Bill this is true, to a point. Not all internal regulators are are temp protected. So one needs to confirm with the manufacture that it is temp protected.

The biggest issue I see is an added layer of in-efficiency. Most alternators have an average of 50% efficiency. This dc to dc charger adds another layer of losses on top.

Lloyd

Originally Posted by goboatingnow

High performance alternators are just that, whether they be automotive, truck or marine. IN modern cars alternators are high output, BMWs larger cars are fitted with a water cooled, 90-150A alternator as standard.

To suggest that "automative" is port quality is to speak out ones behind. Internal regulars are quite sophisticated systems, integrating temperature and load dumping protection , soft start etc.

Utilising an internal regulator and a sterling A2B is merely one way of extracting the alternator output in a manner more suitable to battery charging . It is NOT appreciated by the masses that the primary purpose of the modern alternator is to supply the cars electrical system, NOT to charge the battery. Hence its regulator profile is more suitable to constant voltage PSU type operation.

Sterlings A2B was primarily designed to allow a standard internal regulator to be converted into a better battery charger without needing to replace the internal regulator. Its a clever and sophisticated piece of electronics, that few have bothered to replicate as designing relaible and robust high powered DC-DC convertors is not an easy task.

To say such a method "overloads" or overly stresses the alternator is nonsense. During bulk mode, the alternator will merely output as much as its regulator will allow. As the DCDC unit steps up the voltage to absorption levels, it will suck out more power then a normal regulator would deliver at elevated voltages, but again within the regulators parameters.

This is identical to what a balmar regulator would also do. its merely an external regulator whose profile has been modified or customised to suit 3 stage battery charging as opposed to power generation.


dave

[goboatingnow]

Originally Posted by FlyingCloud1937

Bill this is true, to a point. Not all internal regulators are are temp protected. So one needs to confirm with the manufacture that it is temp protected.

The biggest issue I see is an added layer of in-efficiency. Most alternators have an average of 50% efficiency. This dc to dc charger adds another layer of losses on top.

Lloyd

Increasingly car alternators are actually being controlled by the cars ECU. for example all new fords focus etc in europe and many other Ford models have either Can bus controlled alternators or ECU direct control alternators. The ECU monitors ambient, battery temp, alt temp etc.

It may be salutary to realise that boats have the crapest electrical systems , mor akin to 1960's autos then anything modern on the road today

Think of the range of diagnostic system monitoring a modern car. crank sensing, various temp sensors, air mass, CO levels, etc etc, then compare that to the crap sensing on a standard boat diesel.

I mean you pay $$$$$$$ and you don't even get raw water sensing, then add in pathetic battery management and charging systems , really .... we need to be shouting from the rooftops

its really a joke when you consider it .


dave

[goboatingnow]

The biggest issue I see is an added layer of in-efficiency. Most alternators have an average of 50% efficiency. This dc to dc charger adds another layer of losses on top.

Whether you have a internal or external regulator, alternator efficiencies are essentially the same. Hence the only inefficiency is in the DC DC conversion, this would not be a lot typically 3-6% if designed well. This is only a factor in max power scenarios, when temperature de-rating of the alternator would drown any power conversion losses. IN reality therefore such power conversion losses are not really a factor


dave

[DeepFrz]

IN modern cars alternators are high output, BMWs larger cars are fitted with a water cooled, 90-150A alternator as standard.

$1,200 - $1,500 dealer price plus installation if you don't do it yourself. So don't anyone cry to loudly when they pay premium price for a Balmar alternator.

That's US dollars. I hate to think what it would be in Canada.

[goboatingnow]

Originally Posted by DeepFrz

$1,200 - $1,500 dealer price plus installation if you don't do it yourself. So don't anyone cry to loudly when they pay premium price for a Balmar alternator.

That's US dollars. I hate to think what it would be in Canada.

Hmmm mine was replaced on the RE for a out 550 pounds all in

Dave

[goboatingnow]

Originally Posted by goboatingnow

Hmmm mine was replaced on the RE for a out 550 pounds all in

Dave

Jeepers I hate auto correct

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

Dave


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