Beeps when battery turned on

[Laneman25]

2000 Volvo 5.0 GL. Today at the launch ramp I turned on the battery switch and a beeping sound started. Turned key on and voltage was at 10. Strange thing is it cranked fine so I launched. Ran fine all day but kept beeping for an hour straight, then slowly went away. Every now and then beeping would start and stop. When I put it on the trailer and turned engine off it beeped steady till I turned the battery switch off. Voltage did come up to 12.5 while driving.

 

[cyclops222]

Sounds like a tired battery that charged up. What ran the battery down ? Something left on ? Like a Bilge Pump and Float switch ? Some are very quiet. If covered by a engine or floor boards. Radio with volume way down.
I have done those and a lot more. Fish Finder & Bow lights. Several times.

 

[Laneman25]

Yeah, I noticed the bilge switch and lights were on today. Must have had it on last outing. While parked battery switch is always off.

 

[Donald0039]

There are several things that can drain the battery. CO detector. VP Active Corrosion Protection. Refrig. Stereo on but turned down, cabin lights.

 

[Laneman25]

I wish the indicator lights in the switches were brighter so I can tell in daylight that they are on. Is there a way to add a brighter LED to replace the faint glow of the existing switch light?

 

[Laneman25]

Following up, 7 weeks parked, battery at 12.6 volts. I'm taking it and alternator to be tested. Seems like battery is okay. If alternator tests bad can I use an automotive rebuild kit?

 

[Donald0039]

Following up, 7 weeks parked, battery at 12.6 volts. I'm taking it and alternator to be tested. Seems like battery is okay. If alternator tests bad can I use an automotive rebuild kit?

The battery should be checked with a load tester, not a voltmeter.

If you can, bring the alternator to a starter/alternator rebuild shop that would be best. The problem with the alternator (if there is one) is probably either brushes or a diode. There are 6 diodes in the full wave bridge. And more as part of the voltage regulator. A starter/rebuild shop will have an oscilloscope.

Also some boats wire a few things like bilge pump so they get get power regardless of battery switch.

 

[ESGWheel]

From your initial post you stated the voltage was 12.5 while driving. I assume this is from a helm gauge. Also, I assume that it seemed low to you, i.e., that you normally experience a higher voltage when driving, like 13.8 to 14.2 (which is what you should be seeing when driving). While a helm gauge is no substitute for a good multimeter, if my description is correct, you are correct in thinking you have an issue with your alternator.

• This assumes all connections are good, clean and tight.

While I am unsure what unique features makes a marine alternator SAE J1171 compliant I strongly suspect an ‘automotive’ rebuild kit will work. When you take it in, talk to the folks about this and (assuming they are also doing the repairs) ask them to let you know if anything was ‘different’. Base your next steps on that > ie if they do the repair and mention was a little odd but the repaired alt now works > great, can temporarily use it while you pursue getting a proper marine one. Here is a good source for marine alternators: link. Others exist as well.

Please post how it goes.

 

[Donald0039]

From your initial post you stated the voltage was 12.5 while driving. I assume this is from a helm gauge. Also, I assume that it seemed low to you, i.e., that you normally experience a higher voltage when driving, like 13.8 to 14.2 (which is what you should be seeing when driving). While a helm gauge is no substitute for a good multimeter, if my description is correct, you are correct in thinking you have an issue with your alternator.

• This assumes all connections are good, clean and tight.

While I am unsure what unique features makes a marine alternator SAE J1171 compliant I strongly suspect an ‘automotive’ rebuild kit will work. When you take it in, talk to the folks about this and (assuming they are also doing the repairs) ask them to let you know if anything was ‘different’. Base your next steps on that > ie if they do the repair and mention was a little odd but the repaired alt now works > great, can temporarily use it while you pursue getting a proper marine one. Here is a good source for marine alternators: link. Others exist as well.

Please post how it goes.

I would not make decisions based upon a helm gauge. I would use a decent DVM to verify the reading of the helm voltage gauge. A $40 voltmeter will do. You don't need a Fluke.

 

[Laneman25]

I would not make decisions based upon a helm gauge. I would use a decent DVM to verify the reading of the helm voltage gauge. A $40 voltmeter will do. You don't need a Fluke.

I actually have a Fluke. I am confused that the boat was beeping a low battery warning but it started fine and battery voltage is good. Maybe further testing will reveal something

 

[Donald0039]

I actually have a Fluke. I am confused that the boat was beeping a low battery warning but it started fine and battery voltage is good. Maybe further testing will reveal something

The basic test is to charge the battery on a plug in charger. Disconnect and wait overnight to eliminate the surface charge. Retest with a DVM. Full charge is 12.64 V for a normal lead acid flooded cell battery. With the engine running and alternator working properly the voltage should be at least 1 V higher.

These days with EFI, electronic ignition and warm weather, engines turn over and start pretty easily. So slightly low voltage may still allow the engine to start.

 

[racerone]

A " marine " alternator may be " flame arrested " -----But an automotive repair kit should work.

 

[Laneman25]

Alternator tested good at a reputable rebuild shop. Battery load tested good at Autozone. Cables clean and tight. Out of ideas

 

[cyclops222]

You no longer have any electrical problems.......Relax with the boat again.

 

[ESGWheel]

Laneman: can we go back to your original symptoms of 10 and 12.5 volts? How was this measured? Even if it was ‘an unreliable’ helm gauge does not explain the beeping.

Here is a suggestion to determine all is sound on the in-situ battery / alternator front > using your Fluke attach it to the battery POS and NEG with some good alligator clips with long enough leads to have the meter outside the engine compartment where it can be easily read. Careful of routing to avoid spinning parts

With a helper, monitor the meter voltage during the start cycle. Before starting should be about 12.5 or more and during the cranking it will drop to about 11 or so. If drops to 10 or less > battery issue (or some other excessive draw on the battery due to starter issue or connections). Now that its running kick the RPMs up to 1500 or so to ensure alt is getting good and going. Voltage should be about 13.5 to 14.2. If not, issue with the alt. or some abnormal draw or connections.

• And any beeping going on during this test?

And while you are at it compare the helm gauge with what you are seeing on the Fluke > will provide a sense of the accuracy of the gauge.

Please post results and we’ll go from there and hopefully all is good.

 

[Laneman25]

Laneman: can we go back to your original symptoms of 10 and 12.5 volts? How was this measured? Even if it was ‘an unreliable’ helm gauge does not explain the beeping.

Here is a suggestion to determine all is sound on the in-situ battery / alternator front > using your Fluke attach it to the battery POS and NEG with some good alligator clips with long enough leads to have the meter outside the engine compartment where it can be easily read. Careful of routing to avoid spinning parts

With a helper, monitor the meter voltage during the start cycle. Before starting should be about 12.5 or more and during the cranking it will drop to about 11 or so. If drops to 10 or less > battery issue (or some other excessive draw on the battery due to starter issue or connections). Now that its running kick the RPMs up to 1500 or so to ensure alt is getting good and going. Voltage should be about 13.5 to 14.2. If not, issue with the alt. or some abnormal draw or connections.

• And any beeping going on during this test?

And while you are at it compare the helm gauge with what you are seeing on the Fluke > will provide a sense of the accuracy of the gauge.

Please post results and we’ll go from there and hopefully all is good.

Thank you esg, this is good troubleshooting

 

[Laneman25]

I took the boat out today and everything was fine. Didn't really fix anything, just cleaned the alternator wires some, but they were fairly clean. Volt gauge was at 10 volts during start so I think the gauge is faulty. Thanks for the help everyone

 

[dypcdiver]

Just a quick note, when I start my motor it idles at 650rpm the dashboard gauge remains at 10 volts, but as soon as I rev beyond 1000rpm it goes up to just over 13 volts, it has been like that for 25 seasons, so I have stopped worrying about it.