Alternator internal or external control?

[pbmaise]

On my most recent passage my Leece Neville alternator stopped working.

After a lengthy self education it appears the alternator was modified so it could be controlled by an external Xantrex alternator controller.

The vessel came with a spare alternator that appears to be a more recent model of the problem alternator. It has its own internal regulator.

It appears I have three choices.

#1 Modify the new alternator and defeat the internal controller in a similar fashion.

#2 Use internal controls and defeat the Xantrex

#3 Possible repair of alternator be changing brushes?

Thoughts?

[a64pilot]

1 and 3 get my vote, both.

[billknny]

Assuming that the alternator is an important source of battery juice for your system, 1 and 3. That way you have a drop in spare. If the alternator is just an occasionally used charging source, it doesn’t really matter much.

Alternators are almost always easily rebuilt to like new by a shop with the capabilities, so don’t toss the old one.

[pbmaise]

Thanks I am going with 1 and will take old alternator to repair shop.

The new LN has an internal regulator 102200. I see there already is a blue wire to an external terminal.

Rather than hack out the internal regulator, it seems to make sense to me to just leave it in place and then connect the blue wire from the Xantrex, XAR to that terminal instead of bypassing and going directly to the field.

Right?

[pbmaise]

I have now removed old alternator and wired to the external terminal without changing or removing internal regulator.

I am leery about starting.

I suspect this comment I found in another thread applies..

"I'd wire the Balmar regulator to the positive field I'd wire the Balmar regulator to the positive field connection, and ground the negative field connection. But if the alternator's internal regulator hasn't been disabled, the Balmar won't give a proper 4-step charge cycle, it can only increase the voltage set by the internal regulatorconnection, and ground the negative field connection. But if the alternator's internal regulator hasn't been disabled, the Balmar won't give a proper 4-step charge cycle, it can only increase the voltage set by the internal regulator"

I am not so concerned about step charging.

However,
I am guessing by this comment that unless I defeat the internal regulator I won't be able to switch the alternator off.

Balmar and Xantrex are one in the same external regulator.

Obviously these were sold for a good reason on sailboats.

Is it possible for me to just go with option 2 and not connect the external regulator until I know more?

[pbmaise]

So I first started engine with external controller unattached to the blue wire. Nothing happened and not charging.

I stopped engine connected blue wire from external controller to alternator and then turned on engine. Nothing until I turned switch for external controller on

After flipping switch voltage came up and charging began.

I shut down engine and turned off external controller.

Upon restart even without flipping external controller on the alternator began making voltage. The blue wire was s attached to the external but again the alternator was running despite the external now being off. Actually, that was kind of expected.

What was not expected was not running the first time the engine was on.

Alternator is currently treading with load ramping up nicely. Have yet to see if goes to a float state when batteries are fully charged.

[Maine Sail]

Originally Posted by pbmaise

I have now removed old alternator and wired to the external terminal without changing or removing internal regulator.

I am leery about starting.

I suspect this comment I found in another thread applies..

"I'd wire the Balmar regulator to the positive field I'd wire the Balmar regulator to the positive field connection, and ground the negative field connection. But if the alternator's internal regulator hasn't been disabled, the Balmar won't give a proper 4-step charge cycle, it can only increase the voltage set by the internal regulatorconnection, and ground the negative field connection. But if the alternator's internal regulator hasn't been disabled, the Balmar won't give a proper 4-step charge cycle, it can only increase the voltage set by the internal regulator"

I am not so concerned about step charging.

However,
I am guessing by this comment that unless I defeat the internal regulator I won't be able to switch the alternator off.

Balmar and Xantrex are one in the same external regulator.

Obviously these were sold for a good reason on sailboats.

Is it possible for me to just go with option 2 and not connect the external regulator until I know more?

If the new alt has an internal regulator it needs to be correctly converted to external regulation before it can be used as an externally regulated alternator. Some of those larger LN alts use the stator tap as a way to "excite" the internal regulator. This wire is often blue but it's NOT field. A model number from the alt would help. Do not connect the ext reg until the alt has been properly converted to ext regulation..

Over time (storage) these alts can loose magnetism and may not "self excite" and by wiring the ext reg to the blue wire you likely gave it the boost it needed to excite itself. The internal reg will not drop to float. It's not what they do..

[roland stockham]

Internal regulators have no place on cruising sailboats. The are for cars or motorboats that have the engine running most of the time. To charge batteries you must have a 3 step external regulator. The possible exception is a cat with a massive solar rig as the primary battery charger.

[a64pilot]

That is a little strong, but I will say if offered the choice that a good external regulator is better.

[roland stockham]

Maybe 'a little strong' but any fixed voltage regulator either cannot fully charge batteries because the voltage is too low or will overcharge them when you run for a long period because the voltage is to high.

The required voltage is 14.6 - 14.8v for charge and 13.8v float. You can compromise at 14.2 but charge time will be 6hr+ so they almost never get a full charge. Any higher and you will boil them dry.

Correctly charged good FLA's give a service life of 10yrs +. The main reason for short battery life is incorrect charging.
Sealed batteries will be destroyed even more rapidly without a proper regulator due to water loss
This only applies to cruising boats that do not run a gen-set and are not able to rely on shore power or other sources to ensure the batteries are regularly brought up to full charge

[pbmaise]

Originally Posted by Maine Sail

If the new alt has an internal regulator it needs to be correctly converted to external regulation before it can be used as an externally regulated alternator. Some of those larger LN alts use the stator tap as a way to "excite" the internal regulator. This wire is often blue but it's NOT field. A model number from the alt would help. Do not connect the ext reg until the alt has been properly converted to ext regulation..

Over time (storage) these alts can loose magnetism and may not "self excite" and by wiring the ext reg to the blue wire you likely gave it the boost it needed to excite itself. The internal reg will not drop to float. It's not what they do..

Thanks this is a good explanation of what occurred. I will heed advice and disconnect blue wire until I have time to properly bypass internal controller.

I do indeed normally charge using my 900 watt solar bank and do reach the 14.5 Volts for my FLA bank often.
Therefore, I thing short term on internal controller will not be an issue.


I have a passage coming up and will monitor voltage to prevent overcharging, until I have more time to bypass internal control. Today's project is sewing trampoline. Always something to do.