Help with alternator repair

pablosgirl · August 10, 2016, 04:10:05 PM

Hi,
After 8 months our new Leece-Neville 90 amp alternator failed this morning in Marsh Harbpur, Bahamas. About 45 min into charging the batteries a strong burnt electrical smel occurred and the volt meter dropped from about 14v to around 13 v. The tack kept working. I think the internal voltage regulator fried? I ran the engine to move the boat and it looked like the alternator was working again until I reached 13.5 v and the voltmeter then dropped to 12.5 v. I am going to swap in the old Motorola 55 amp with the Spa-Creek regulator and have the new one tested. Being in the Bahamas, not sure on parts avalinility. I called ASC Supply where I bought it, but the only way to get it repaired under warinty is to send it in. Trying to make it back to Texas by mid Sept and can't wait that long here.

Anyone have any experience with repairing voltage regulators? I am assuming one or more of the diodes in the regulators bridge circuit has failed? Any help would be greatly appreciated.

Ken Juul · August 10, 2016, 05:12:16 PM

Diodes are diodes. It won't be under warrenty, but I'm sure there is a shop in one of the more populated islands that can fix it. Ask the locals and any marina's you are near.

Ron Hill · August 11, 2016, 02:28:34 PM

Paul : I believe that your putting back on the old 55amp Motorola is your best bet.

As I recall a gallon of RO water was more than a gallon of diesel!! I hope things have gotten better, but doubt it!

A thought

pablosgirl · October 07, 2016, 11:28:16 AM

We are back in Texas and I sent the bad alternator in to see if it was covered under warranty. I am confused by their answer:

"I have inspected your alternator and it has blown diodes and bad stator which is caused by overcharging and is not a manufacture defect. This is not covered under warranty and suggest possibly bad batteries."

I explained what my set up was and they said that this alternator was only meant to charge "starting" batteries and not deep cycle batteries. But yet Mainsail uses this alternator in some applications which I have tried to duplicate on my boat minus the external regulator. Am I getting the run around or am I missing something here?

I bought 4 new GC2 190AH golf cart batteries when I purchased this alternator and never let the batteries get bellow %50. So I have a theoretical usable capacity or 190 x .8 or 152Ah and my energy budget is 120Ah peak usage. so the bank size should be right. I am using the internal regulator of the alternator to control charging. I ran the engine 1hr in the morning and 1 hr in the evening to keep the batteries up. So I am confused as to why an alternator "marine grade" is burning itself up. When charging I would watch the voltage go from just over 12v to 14v in about 15 -20 minuets. I thought this would be the point where the internal regulator would hold the voltage constant and dial back the amperage as the battery charges through the absorption phase.

I am trying to understand if I am being taken here or do I need to do something else to avoid burning up the replacement alternator.

Paul

Stu Jackson · October 07, 2016, 12:13:11 PM

Quote from: pablosgirl on October 07, 2016, 11:28:16 AM
.................................................But yet Mainsail uses this alternator in some applications which I have tried to duplicate on my boat minus the external regulator. Am I getting the run around or am I missing something here?

Paul,

What you're missing is what Maine Sail & I have been "preaching" for the past decade or more.

He uses amp/belt manager AND temperature compensation with external regulators. I choose to use manual Small Engine Mode. Both of these are covered in the Electrical Systems 101 topic in great detail.

Using that alternator on a 50% SOC large house bank WITHOUT an external regulator (and its controls) will, and did, result in your situation.

Either have them fix it or find a local alternator repair shop (as I did and recommend to everyone).

And invest in a Balmar MC-614.

Ron Hill · October 08, 2016, 12:12:16 PM

Paul : I agree with Stu.
What I got out of the answer from your warrantee query, is that you should have had an external voltage regulator which would have protected the alternator!!

A thought

mark_53 · October 08, 2016, 02:33:41 PM

Just curious as to how the 55 amp Motorola worked out. I assume no issues with that internal regulator. The reason I ask is I am still using the 55amp Motorola to charge both my house and start battery through an ACR. Is this a problem only with higher output alternators?

Stu Jackson · October 08, 2016, 03:43:41 PM

Quote from: mark_53 on October 08, 2016, 02:33:41 PM
Just curious as to how the 55 amp Motorola worked out. I assume no issues with that internal regulator. The reason I ask is I am still using the 55amp Motorola to charge both my house and start battery through an ACR. Is this a problem only with higher output alternators?

The issue is a high output alternator on a LARGE house bank that is (deeply) discharged, thus requiring the high output WITHOUT amp/belt manager or Small Engine Mode. This ends up overheating the alternator and burning up diodes and stators.

How big is your house bank and what kind of batteries? How deeply do you discharge the bank? Do you marina-hop or anchor out?

From this link below is this:

Automotive Alternators vs. Deep Cycle Battery banks (by Maine Sail) (NEW March 2016)

http://www.pbase.com/mainecruising/automotive_alternators_vs_deep_cycle_batteries

Dumb Regulator - (Non thermistor model) This can do fine provided you have minimal voltage drop in the system and it regulates to around 14.4V or so and matches the absorption set point of your batteries. While a single absorption voltage is arguably less than ideal if you are not a full time cruiser an arrangement like this can work perfectly fine. Be aware that with a large bank you can literally burn up a "dumb regulated" alternator because it has no self protective features.

mark_53 · October 08, 2016, 05:50:25 PM

Quote from: Stu Jackson on October 08, 2016, 03:43:41 PM
Quote from: mark_53 on October 08, 2016, 02:33:41 PM
Just curious as to how the 55 amp Motorola worked out. I assume no issues with that internal regulator. The reason I ask is I am still using the 55amp Motorola to charge both my house and start battery through an ACR. Is this a problem only with higher output alternators?

The issue is a high output alternator on a LARGE house bank that is (deeply) discharged, thus requiring the high output WITHOUT amp/belt manager or Small Engine Mode. This ends up overheating the alternator and burning up diodes and stators.

How big is your house bank and what kind of batteries? How deeply do you discharge the bank? Do you marina-hop or anchor out?

From this link below is this:

Automotive Alternators vs. Deep Cycle Battery banks (by Maine Sail) (NEW March 2016)

http://www.pbase.com/mainecruising/automotive_alternators_vs_deep_cycle_batteries

Dumb Regulator - (Non thermistor model) This can do fine provided you have minimal voltage drop in the system and it regulates to around 14.4V or so and matches the absorption set point of your batteries. While a single absorption voltage is arguably less than ideal if you are not a full time cruiser an arrangement like this can work perfectly fine. Be aware that with a large bank you can literally burn up a "dumb regulated" alternator because it has no self protective features.

Stu:
My house batteries are 2 group 27 marine FLA batteries (DiHard?). My start is a group 24 FLA. I do anchor out for a week or so at the most. Don't typically go below 50% SOC but may hit that occasionally. Use the engine to give a recharge and warm up the hot water every other day.

Stu Jackson · October 08, 2016, 05:57:55 PM

Quote from: mark_53 on October 08, 2016, 05:50:25 PM
Stu:
My house batteries are 2 group 27 marine FLA batteries (DiHard?). My start is a group 24 FLA. I do anchor out for a week or so at the most. Don't typically go below 50% SOC but may hit that occasionally. Use the engine to give a recharge and warm up the hot water every other day.

You should be just fine. A relatively small house bank. FLA batteries (vs. AGM which can draw much higher current). If it ain't broke... I ran our OEM Motorola for many years with a Spa Creek AutoMac and did just fine before I upgraded to a 100A alternator with the external MC-612.

In your case, and not covered by Maine Sail, is that between the dumb regulator and the low battery acceptance, you're fine. It's between the lines in his writeup: he does a good job of explaining the difference between alternator and battery wants & needs.