Internal alternator regulator or external

[leftbrainstuff]

Originally Posted by geoffr

We are in the process of replacing our old Yanmar with a 3YM30AE ( YANMAR | 3YM30AE ). The YM30 comes with a 125A alternator which is internally regulated. Our old engine had an external regulator and I am wondering if I should also get one for this new alternator. The old regulator is unusable due to it's age so I am considering a Balmer MC-614-H or ARS-5-H.

What advantages would I have using an external regulator?


House bank is currently 6 T-105s (675AHr)
Start batter and Thruster battery charged via Balmer Digital Duo Chargers

Geoff.

I'm not familiar with any internal regulators that would properly charge a house bank.

If it has over temp protection it might work but its designed duty cycle would not be suitable fot charging your house bank.

We have 3 alternators, 55 and 130 on the main engine and a 130 on the generator. All have external regulators, identical, and we carry a spare.

Lots of redundancy. Plus each regulator is configured to our battery configurations.

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[GrahamHO]

Originally Posted by leftbrainstuff

I'm not familiar with any internal regulators that would properly charge a house bank.

If it has over temp protection it might work but its designed duty cycle would not be suitable fot charging your house bank.

We have 3 alternators, 55 and 130 on the main engine and a 130 on the generator. All have external regulators, identical, and we carry a spare.

Lots of redundancy. Plus each regulator is configured to our battery configurations.

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I can't imagine how Captain Cook managed all his voyages without electricity.
Mainly using skill I suppose.

[Abgreenbank]

Have a yanmar engine with 120amp alternator, and ribbed belt, fitted a stirling power alt to battery charger, if my 700 amp hr bank is reasonably discharged, if I charge with the alternator, the battery bank is still getting over 100amps charge after an hour, so I guess it works, it has a temp sensor on a battery post but I guess 100amps isn't going to heat up a large bank too quickly.
If it fails, back to the normal hitatchi regulator, and as I haven't tampered with the innards of the alternator shouldn't be any warranty problems.
Regards
Ab


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[Stu Jackson]

This is a good analysis.

Except It All Depends on What You are Trying To Do.

If it is to protect the alternator, sure, you're right.

If it is to charge a house bank of batteries, it simply sucks.

What's so hard? Maine Sail explained it all in the full link.

The TRICK is to avoid extra pulleys and double belts, and get a larger alternator, say in the range of 100A or a tad more, use a single belt and use the Amp Manager and/or Small Engine Modes available with external regulators. Works great with my 390 ah house bank.

This information has been available on the internet for quite some time, and is included in the links I provided.

Maine Sail's website has tons, and here's even more, including links to his:

Electrical Systems 101

Good luck.

Originally Posted by OceanSeaSpray

When I read:

"Hitachi & many other automotive alternators with dumb regulators, limit voltage but also reduce voltage based on alternator temperature. This is a self protective feature installed in the internal dumb regulator to prevent the alternator from cooking itself. In cars it is usefully "safe", due to super high engine bay temps, but on boats temp sensing should be done directly at the battery not inside the alternator.
..."

I can't help but wonder who is "really, really dumb" to borrow a few more words from the author. It is an idiotic statement. Sensing alternator temperature is a protective measure intended to prevent alternator failure by overheating indeed. So, by extension, the smart move is allowing it to cook itself instead. Sensing battery temperature is intended to correct the charging voltage according to ambient temperature. The two purposes are completely different.

Alternators also get much better cooling on vehicles where there is ample air circulation than within the confines of an engine compartment on a boat. Trying to cool them with air at 50degC already is not that great.

Ducting the engine bay air supply to the back of the alternator would help a great deal for a start.

[wsmurdoch]

Originally Posted by 01kiwijohn

I'll skip all the theory;
I have a Yanmar 30GM and replaced the original alternator with an 80 amp (max I can use with single belt) from DB Electrical ( direct fit replacement).
I added an external Sterling regulator, which brings my battery bank up, from about 60%, in about 50 mins or so. The regulator has a temp sensor to protect things. So far, 3 years ( we live aboard, and mostly anchor out for 5 months per year) and the whole system has been trouble free.
A few of my acquaintances have Balmar set ups, and most have some kind of "issue".
Good luck and let me know if I can help you with it.

I also have an alternator from DB Electrical. They are about 3 miles from my house. Good people. For my Yanmar 3HM35F they recommended a knock off Chinese made Delco CS-130 alternator with the field wire brought out. I bought two for about $75 each (yup $75); one to use and one for a spare. I did the alternator wiring modification myself following their instruction. A Xantrex XAR external regulator with temperature sensors on both the alternator and the battery controls the alternator. (It is the second Xantrex XAR; the first failed when water got under the potting compound.) After 8 annual trips to the Bahamas, we are still on the original alternator and the spare is still under the port settee. At 105 amp max output the alternator is capable of eating a 1/2" vee belt when operating at maximum output at low engine rpm for a long period of time. Also, when operated at a high output with a low (1200-1500 engine) rpm the alternator will overheat due to low air flow due to the low alternator fan speed. Speed things up or switch to small engine control and all is fine.

I'm happy.

www.irish-eyes-to-the-bahamas.blogspot.com

[OceanSeaSpray]

Originally Posted by Stu Jackson

Except It All Depends on What You are Trying To Do.

Well, I have never been very successful at charging house banks with fried alternators.
The same people should also disconnect the engine over-temperature alarm so they can keep running a little longer if they ever lose cooling.

In my experience, it doesn't usually happen right away: a great deal of self-congratulation first follows the modification.
Then one day the bank is low, there is a lot of wind, something happens and the engine is needed at high revs for quite a while to get out of it. Then it happens. The funny smell, zero charging current...

Not many small frame alternators are very happy above 80% rated output for a long time and I have measured stators above 140degC. Not very clever.
Either use a unit that handles the load, or make sure it is thermally protected.

[OceanSeaSpray]

Originally Posted by wsmurdoch

At 105 amp max output the alternator is capable of eating a 1/2" vee belt when operating at maximum output at low engine rpm for a long period of time. Also, when operated at a high output with a low (1200-1500 engine) rpm the alternator will overheat due to low air flow due to the low alternator fan speed.

These problems can be fixed very easily by limiting the maximum field current (=torque absorbed). Sometimes you can preset this on the external regulator, otherwise just insert a power resistor in the field circuit, something like 1Ohm / 20W. Sometimes it takes a bit of trial and error to get the right value. It usually ends up in the range of 0.5 - 1.5Ohms.

It is a huge boost in reliability for just a few dollars at the most.

[wsmurdoch]

Originally Posted by OceanSeaSpray

These problems can be fixed very easily by limiting the maximum field current (=torque absorbed). Sometimes you can preset this on the external regulator, otherwise just insert a power resistor in the field circuit, something like 1Ohm / 20W. Sometimes it takes a bit of trial and error to get the right value. It usually ends up in the range of 0.5 - 1.5Ohms.

It is a huge boost in reliability for just a few dollars at the most.

Exactly. It is just what I do but by a different route. It is easy, cheap, and effective (at least for me).

When operated at low rpm (like charging at anchor) the alternator turns slowly and its fan turns slowly. With a high demand on the alternator (like 75 amp or more of its 105 amp capacity) the alternator gets hot, and if left alone its temperature sensor will cut the field current from the external regulator to the alternator dropping the alternator output current to about half (105 amp back to 50 amp). I have a switch installed to short the leads of the temperature sensor together and fool the external regulator into thinking the alternator is hot. Throwing the switch preemptively cuts the alternator back to 50% which not only keeps the alternator cool, it also takes half the load off the belt. It is all in the installation manual for the Xantrex XAS regulator.

"8. Attach optional Alternator Temp Sensor to the Alternator Temp
Sensor terminals shown in Figure 6. Observe polarity. Attach sensor
to alternator case as shown in Figure 3. Installing a toggle switch
between the positive and negative terminals of the Alternator
Temperature Sensor circuit allows you to reduce alternator output and
horsepower load by 50% (Small Engine Mode)."

At a higher engine rpm the alternator fan moves enough air to keep the alternator cool, and at a higher engine rpm the faster belt speed means the belt tension needed to transfer the needed power to the alternator is less. At higher engine rpm I can run the alternator at its full potential without the alternator overheating or the 1/2" belt dusting. I just switch the switch.

Like you said "...a huge boost in reliability for just a few dollars...".

[Stu Jackson]

The Balmar MC-612 I have calls this "Small Engine Mode" which I mentioned earlier and is exactly what I do.

You're right, it always helps to RTFM.

These are included in my last Electrical Systems 101 link:

Alternator heat, Regulator Controls, Small Engine Mode

Alternator heat, Regulator Controls, Small Engine Mode

Small Engine Mode - discussion with link to the picture of the toggle switch: Alternator heat, Regulator Controls, Small Engine Mode

Small Engine Mode - the picture of the toggle switch Alternator Output Management with External Regulators [Small Engine Mode]

Originally Posted by wsmurdoch

Exactly. It is just what I do but by a different route. It is easy, cheap, and effective (at least for me).

When operated at low rpm (like charging at anchor) the alternator turns slowly and its fan turns slowly. With a high demand on the alternator (like 75 amp or more of its 105 amp capacity) the alternator gets hot, and if left alone its temperature sensor will cut the field current from the external regulator to the alternator dropping the alternator output current to about half (105 amp back to 50 amp). I have a switch installed to short the leads of the temperature sensor together and fool the external regulator into thinking the alternator is hot. Throwing the switch preemptively cuts the alternator back to 50% which not only keeps the alternator cool, it also takes half the load off the belt. It is all in the installation manual for the Xantrex XAS regulator.

"8. Attach optional Alternator Temp Sensor to the Alternator Temp
Sensor terminals shown in Figure 6. Observe polarity. Attach sensor
to alternator case as shown in Figure 3. Installing a toggle switch
between the positive and negative terminals of the Alternator
Temperature Sensor circuit allows you to reduce alternator output and
horsepower load by 50% (Small Engine Mode)."

At a higher engine rpm the alternator fan moves enough air to keep the alternator cool, and at a higher engine rpm the faster belt speed means the belt tension needed to transfer the needed power to the alternator is less. At higher engine rpm I can run the alternator at its full potential without the alternator overheating or the 1/2" belt dusting. I just switch the switch.

Like you said "...a huge boost in reliability for just a few dollars...".

[OceanSeaSpray]

Originally Posted by wsmurdoch

Exactly. It is just what I do but by a different route. It is easy, cheap, and effective (at least for me).

Yes, I got that. But you have a manual system and you need to manage the switch.

If you add a resistor like I was describing, what happens is that you tune the alternator torque curve to suit your installation and it becomes usable throughout the whole rev range without switching anything or overheating.

It is very effective, because stator heating varies with the square of the current: if you run 80% of the current at a given RPM, you only incur 64% of the heating.

When the sensor cuts it back, it tends to be more aggressive, because by then you are too hot already.

I de-rate alternators this way all the time.

[GrahamHO]

Originally Posted by OceanSeaSpray

Yes, I got that. But you have a manual system and you need to manage the switch.

If you add a resistor like I was describing, what happens is that you tune the alternator torque curve to suit your installation and it becomes usable throughout the whole rev range without switching anything or overheating.

It is very effective, because stator heating varies with the square of the current: if you run 80% of the current at a given RPM, you only incur 64% of the heating.

When the sensor cuts it back, it tends to be more aggressive, because by then you are too hot already.

I de-rate alternators this way all the time.

I do similar simply with an alternator pulley 10 mm larger diameter. Go figure.

[OceanSeaSpray]

Originally Posted by GrahamHO

I do similar simply with an alternator pulley 10 mm larger diameter. Go figure.

Yes, this can work too, especially for belt problems and it can knock down the maximum output. The difference is that it doesn't improve cooling. The resistor reduces the output for the same fan RPM.
When the field wiring is already coming out to go to an external regulator, de-rating with a power resistor is one of the easiest thing to do. I have also done it to internally regulated alternators and then it is a matter of tapping into the slip rings circuit: disconnect one of the wires going to a brush and insert the resistor there.

[GrahamHO]

Originally Posted by OceanSeaSpray

Yes, this can work too, especially for belt problems and it can knock down the maximum output. The difference is that it doesn't improve cooling. The resistor reduces the output for the same fan RPM.
When the field wiring is already coming out to go to an external regulator, de-rating with a power resistor is one of the easiest thing to do. I have also done it to internally regulated alternators and then it is a matter of tapping into the slip rings circuit: disconnect one of the wires going to a brush and insert the resistor there.

Slowing the alternator a little doesn't affect its output at cruising rpm. It will affect it a little at idle or slow speeds.

Motor cars used to have generators. One reason cars changed to alternators was to maintain a satisfactory output, going slow and idling in traffic. So on a modern commute your car engine might not often run over 2000 rpm apart from a few times in a lower gear. For long periods it might be running 1000 / 1500 rpm.
Even cruising down a freeway at 80 mph cars are only running about 2800 rpm depending on the car. They also need to drop a gear and run up to maybe 6000 rpm for a short time.

Boats don't need the engine speed, and therefore the alternator speed to work over such a large rev range. As we know from cars, alternators give a good charge at lower speed.

With boats we don't want to be running on idle for long periods. Boats are likely cruising around 3000 rpm (we do). I know we are discussing alternator speed, not engine speed but they are of course related. You will find that at those cruising rpm, slowing the alternator a couple of hundred RPM makes little or no difference to the output.

The 10 mm larger pulley increases belt wrap and decreases the load and therefore slip when accelerating from idle to cruising speed.

It works very well for me in conjunction with an Ample Power smart regulator. I don't have an overheating problem, with my alternator having a good supply of cooling air. The smart regulator is cutting back the charge rate after an hour anyway, by which time the batteries are fully charged or close, and after that in the usual steps.

If you don't believe it you should try it. Or if you have spare time look at the alternator outputs V speed graphs.

[Stu Jackson]

Originally Posted by OceanSeaSpray

Yes, I got that. But you have a manual system and you need to manage the switch.

..................................

I de-rate alternators this way all the time.

Understood, good idea.

These alternator questions come up so often, it's a wonder how anyone learned all this stuff without the internet, like we did.

[OceanSeaSpray]

GrahamHO, we are in agreement on everything here... there is nothing for me to try. Alternators on modern marine engines are often run at quite high RPMs, so they can charge decently at idle already. It can put a lot of load on the belt.

I was talking about de-rating the alternator. As you just said, slowing it down a little doesn't really do it. But adding a field resistor does and it keeps the cooling up.

I charge lithium iron phosphate batteries and engineer these systems. De-rating and managing torque is necessary or you fry them up. This is how I do it.