Alternator "Hunting"

[Administrator]

I just replaced the house batteries, and now my charging system "hunts" (if that is the expression) when the engine is running and the batteries are fully charged. The system has a Balmar Max Charge MC-512 regulator.

By hunting, I mean that the system is charging, and then not charging, at somewhere around one-second intervals. It's "Yes, I do, No, I don't need to be charging."

Prior to replacing these batteries, I didn't have this issue, but the batteries were in such poor shape that they couldn't be fully charged, no matter what. At the dock, the battery charger ran constantly.

I vaguely remember sporadically having this problem years ago, and making it go away by turning on several lights in the cabin to apply a load.

I don't like the stress this is putting on the system, and I sometimes hear a bit of a squeal oscillating in time with the hunting.

Any thoughts?

Bill

[ndutton]

Can you list the parameters you have programmed into the MC-512?

[Administrator]

PRG-2.

BTW, the new batteries are the exact same make and model as the old ones.

Bill

[joe_db]

This used to drive us nuts with alternator-driven tachs. Back in the day we would wire an "engine room light" as a load to keep the alternator going. Some newer regulators have a "tach keep alive" setting to prevent this issue.

[ndutton]

Understood, same brand, size and model batteries. Something that catches my eye, can you tweak the parameters within a preset program? I'd try changing Volt Analysis/Switches from Volt Sensitive to Average and see if it makes a difference. Being an old school flooded battery guy I can't say if changing that parameter affects Gels adversely however. Except for minor voltage differences within the programming the Volt Analysis setting is the only one I see dramatically different from the rest.

Joe's experience means much more than my speculation though.

[joe_db]

A battery with a bad cell will always load the alternator up some, so this may be why the issue was not apparent before. Note this is just esthetics - you don't like seeing the regulator cycling - and not harmful.

[Administrator]

This used to drive us nuts with alternator-driven tachs. Back in the day we would wire an "engine room light" as a load to keep the alternator going. Some newer regulators have a "tach keep alive" setting to prevent this issue.

It is an alternator-drive tach. The regulator itself is now 18 years old. Certainly, a back-in-the-day system, and the engine room light comment fits with my vague recollection of turning on lights.

Tnx for these comments.

Bill

[Administrator]

I got this amazingly prompt response from the tech support guy at Balmar:

The problem occurs when the batteries are fully charged and in good condition. The regulator regulates at its set point but there is enough AC pulse that gets through which the battery sees. With very little load the battery keeps the voltage above set point for just enough time for the regulator to turn off for a moment. Adding load does keep the alternator turned on. The solution I recommend on our newer digital regulators is to increase the float voltage. The MC-512 was only produced for a short time and the persons that knew the ins and out of it have retired. I have a call into one of those persons to tell me if it is possible to do that on the 512. If you should want to upgrade the replacement for the 512 is either the ARS-5-H or the MC-614-H. If I hear back from Steve I will email you what I find out.

Bill

[Van_Isle]

Not many companies out there that go to that kind of effort (or any!) to support legacy products.

[ndutton]

May I ask the age of your gels that were replaced?

[Administrator]

Gulp....

The batteries were Deka's and were installed in 1999. They were kept fully charged when on the hard over the winter months.

Not the best example of my passion for preventive maintenance.

I am unable to find the paperwork to determine what warranty coverage I might have.

Bill

[ndutton]

Wow, 18 years. Very impressive.

[sastanley]

Yeah...+1 if you got 18 years..I mis-read your post and was thinking 2009, so I said to myself, "hmm, 8 years out of gels isn't too bad", until I read Neil's post with the correct math, and then I said, ""

[joe_db]

Yeah...+1 if you got 18 years..I mis-read your post and was thinking 2009, so I said to myself, "hmm, 8 years out of gels isn't too bad", until I read Neil's post with the correct math, and then I said, ""

The gel starting battery I used for many years was dumped in our battery recycle pile. I charged it up and it worked fine

[ndutton]

What's good to know is if you're spending twice as much as an equivalent lead acid batt it ought to last twice as long.