Voltmeter

rukidn

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Apr 23, 2012
160
Catalina 310 258 Sandusky, OH
We just completed a week of long distance motoring, with multiple 60-80 mile legs. (Minimal wind for most of the trip). We noticed that the voltmeter had become "noisy", varying rapidly by about +/- one volt. The tach and other instruments are rock steady. The batteries are charging and we noted the charge voltage reduction as they reached full charge. I opened the instrument pod and checked all connections, which were solid. Voltmeter reads steady with engine off.

Original alternator with 500 hours. I would think if a bad diode, we'd see noise on the tach. Next visit will check belt & tension, plus hook up a scope at the alternator to get a true picture of voltage. Any ideas or suggestions?

Thanks, /Ed
 
Mar 6, 2008
1,078
Catalina 1999 C36 MKII #1787 Coyote Point Marina, CA.
Yes, alternator has a ground post, but not used, it is assumed the engine ground is sufficient. This intermittent ground can cause failure of the alternator. That is what happened to me. Run a #8 cable from alternator ground lug to the battery shunt side and see if the problem goes away. Also check if the alternator bracket is broken or cracked.
 
Oct 3, 2011
825
Anam Cara Catalina 310 Hull #155 155 Lake Erie/Catawba Island
We have replaced a couple of our gauges, but also love the voltmeter in the cabin , checks volts in both batteries, FOR REAL!
 
Nov 16, 2012
1,037
Catalina 310, 2000, #31 31 Santa Cruz
Maybe get a digital volt meter in the cabin. I pay no attention to my analog meter on the panel.
I've looked for a digital meter that could replace the analog one, but no luck finding anything that is a drop in fit. That said, I've got three other meters right there, so it's not a big deal.
 
Feb 17, 2006
5,274
Lancer 27PS MCB Camp Pendleton KF6BL
That, to me, just looks like vibration reaction. Maybe the needle needs to be tightened up.
 
Apr 19, 2020
64
Catalina 310 Kenosha, WI
I've looked for a digital meter that could replace the analog one, but no luck finding anything that is a drop in fit. That said, I've got three other meters right there, so it's not a big deal.
These digital volmeters are handy (although not a drop in replacement) and they have a few mounting options that might work for you. Digital Meters | Powerwerx
 
May 2, 2020
30
Catalina 36 MkII 1778 Venice, FL
Mine has the same problem. I replaced an amp meter with a volt meter and when the key is turned, which activates the fuel pump, the ticking of the fuel pump seems insync with the oscillating volt meter. May be just a coincidence. I need to recheck my wiring to a wiring diagram that includes a volt meter.
 
Nov 16, 2012
1,037
Catalina 310, 2000, #31 31 Santa Cruz
These digital volmeters are handy (although not a drop in replacement) and they have a few mounting options that might work for you. Digital Meters | Powerwerx
I bought the Blue Sea 1733, but still haven’t mounted it. I was thinking of putting it at the helm, to keep track of the house batteries while out sailing. I’ve actually got a Balmer Smart gauge, and a Victron monitor at the nav station, so there’s plenty of voltage displays belowdecks.
 
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Nov 16, 2012
1,037
Catalina 310, 2000, #31 31 Santa Cruz
Mine has the same problem. I replaced an amp meter with a volt meter and when the key is turned, which activates the fuel pump, the ticking of the fuel pump seems insync with the oscillating volt meter. May be just a coincidence. I need to recheck my wiring to a wiring diagram that includes a volt meter.
Sounds like there’s a small voltage drop caused by the fuel pump starting and stopping.