Balmar over voltage question

[2atsea]

On our catamaran we have a pair of Balmar, 6 Series, Alternators with Balmar MC-612 regulators joined by a centerfield. No problems for 7 years. Recently, we have experienced a short duration (2-5 sec) voltage spike of more than 16 volts at the battery. Our VHF sounds an alarm if the voltage exceeds ~ 15.5 volts. If I’m quick I can see the analog volt meter pegged at max; greater than 16 volts. We’ve had 3 events in the past 3 days seemingly at random and hard to diagnosis. Next trip out I’ll run mostly with one engine and see if it still occurs. Any thoughts or comments would be appreciated.

Jim
s/v Imagine

[DeepFrz]

Check your sense wire connections.

[David M]

I agree. It sounds like a loose voltage sensor wire. I would check that before you do anything. Don't wait for a 16 volt voltage spike to possibly cause damage to your electronics.

[2atsea]

Thanks guys.

The connections visually look ok. But when I wiggle one the resistance changes a bit. So I replaced that connector. I'll know more next week when we do some motoring.

Jim

[David M]

With all of your boats electronics turned off, start your engine dockside and try wiggling all of the wires at your alternator. Does the system voltage spike? I think the chances are pretty good that you will isolate the problem down to one wire....if you have not fixed the problem already by changing out that connector.

[sailalibi]

Same type of problem with my 612...the spade conn(male) at the regulator was corroded. The 612 is located under the galley sink and got a little "moist" over the years.

[cwyckham]

I had a similar problem. It wasn't the sense wire, it was the 612 ground wire. You need both to be solid to get a true reading.

[hellosailor]

Could be worth temporarily rigging a large digital voltmeter where it can be watched. If anything in the regulation goes nuts, an alternator can burn itself out in 30 seconds. If it only goes a little crazy, 16 or 17 volts on the system can eat a lot of electronics and lighting.


Very much worth some immediate & thorough testing, and if it is something as easy to fix as a corroded or loose wire...MUCH cheaper to fix the wire.


We diddle the clocks an hour this weekend: Consider it well spent on your alternator.(G)