Voltage Meter Issue

[Anon 156829]

Hello,
My Catalina 310 has an ongoing issue related to voltage readings.
My voltage meter pins itself (15-16) from time to time. Usually when a load is introduced.
After replacing battery 1, things seemed to settle down. Then I activated my auto pilot the other day and that sent my volt meter into hyper mode.

I have 2 Interstate SRM 4D batteries. Just replaced Battery 1 as the issue seemed to be isolated to it. Now the issue has reared itself with both batteries. Replaced the alternator as well (regulator is built in to alternator). The issue is intermittent. Sometimes it works fine and sometimes not.

Wondering if the Volt meter is the next swap out.

* Yes the batteries have been load tested resulting in replacement of Battery 1. All connections have been inspected and secured. Don't think its the regulator as it is built in to Alternator and that is brand new.

Any thoughts are appreciated.

 

[kloudie1]

If it pegs out only when the engine is running, probably voltage regulator.. if it pegs out with engine off, then it is the voltmeter.

 

[Ralph Johnstone]

Next time it happens, check your batteries with a digital voltmeter and find out exactly what's going on.

And stop replacing things until you find out exactly what's wrong with your electrical. You're going to go bankrupt .

 

[jssailem]

You're going to go bankrupt

Some boat owners have a bigger boat budget than others. It seems that one can just go to the store and stick a new something into the boat and all will be well. Imagine what would happen to a town if the manager took that approach. Oh there is a pothole on Main Street. Let's replace the street. Not a sustainable approach.

Your volt meter (VM) is trying to tell you something is wrong. Now that said the VM only takes a glimpse at one point in your system. You need to isolate the problem. This involves systematic trouble shooting. Since winter is upon us it is an excellent time to brush up on the electrical system of your boat. Armed with this knowledge you can begin to test the circuits with a DVM (an accurate digital volt meter) and isolate the problem. The you can fix the problem, save money and know you have solved that problem.

It is a boat and other issues will occur, butt you have fixed that problem. It is likely not going to reappear for several years.

 

[Don S/V ILLusion]

V =RI.
Simplistic answer-
as resistance (as in a bad connection) increases intermittently, that is a good indication voltage will follow that intermittent pattern. When did you last open, clean and reconnect all connections? That should be the first thing to try before driving to the store.

 

[Anon 156829]

Next time it happens, check your batteries with a digital voltmeter and find out exactly what's going on.

And stop replacing things until you find out exactly what's wrong with your electrical. You're going to go bankrupt .

Went through the battery test routine along with a load test/recovery and that showed battery 1 was not able to rebound, thus the replacement.

 

[Anon 156829]

V =RI.
Simplistic answer-
as resistance (as in a bad connection) increases intermittently, that is a good indication voltage will follow that intermittent pattern. When did you last open, clean and reconnect all connections? That should be the first thing to try before driving to the store.

Prior to my load test/recovery all connections were inspected and confirmed secure. The load test showed battery 1 was failing - so replaced it. Thx

 

[Stu Jackson]

Went through the battery test routine along with a load test/recovery and that showed battery 1 was not able to rebound, thus the replacement.

Prior to my load test/recovery all connections were inspected and confirmed secure. The load test showed battery 1 was failing - so replaced it. Thx

I think what both Don & Ralph were saying to you was not related to your battery, but rather to the voltmeter itself.
Experience in cockpit panels is that they are a pretty harsh environment and altogether too often overlooked for routine checking of connections to the back of the meters installed in them. Why? Because they are a PITA to open up and check.
So...have you checked the connections at the back of your cockpit panel mounted voltmeter?

 

[Anon 156829]

If it pegs out only when the engine is running, probably voltage regulator.. if it pegs out with engine off, then it is the voltmeter.

I think what both Don & Ralph were saying to you was not related to your battery, but rather to the voltmeter itself.
Experience in cockpit panels is that they are a pretty harsh environment and altogether too often overlooked for routine checking of connections to the back of the meters installed in them. Why? Because they are a PITA to open up and check.
So...have you checked the connections at the back of your cockpit panel mounted voltmeter?

Yes, pulled the panel apart and checked them too. Thanks

 

[Ralph Johnstone]

Super simple answer :

WHAT DO YOUR BATTERY TERMINALS SHOW WHEN THE PANEL VOLT METER SHOWS 16V ?

Good God, this is proving to be more difficult than world peace.
It only requires a grade four reform school education.

Arrrrrrggggggggghhhhhhhhhhhhh

 

[Anon 156829]

Super simple answer :

WHAT DO YOUR BATTERY TERMINALS SHOW WHEN THE PANEL VOLT METER SHOWS 16V ?

Good God, this is proving to be more difficult than world peace.
It only requires a grade four reform school education.

Arrrrrrggggggggghhhhhhhhhhhhh

Super simple answer :

WHAT DO YOUR BATTERY TERMINALS SHOW WHEN THE PANEL VOLT METER SHOWS 16V ?

Good God, this is proving to be more difficult than world peace.
It only requires a grade four reform school education.

Arrrrrrggggggggghhhhhhhhhhhhh

They are normal. Unlike your response. Don't respond if you can't be civil.

 

[Ralph Johnstone]

They are normal.

Why couldn't you have said that in the beginning and saved everyone here from all this head scratching.

I am going to assume here that "normal" means between 12.2V when not charging (engine off) and anywhere up to 14.2V when charging. You have an internal reg. on your alt. so it would not be much more.

- please post actual numbers you have seen on the battery terminals with a DVM when the panel shows 15 - 16V.
- are you charging at that time ?
- what is your electrical load (appliances) at that time ?

 

[Tin Kicker]

Check for resistance to both ends of the regulator sense wire or use a jumper to bypass it, then try flipping loads on and off.

 

[JoeWhite]

If your regulator ground lug has no wire connected, then install a stranded #8 wire to the shunt.

 

[Leeward Rail]

Don't think its the regulator as it is built in to Alternator and that is brand new.

That means nothing. If I had a £ for every brand new alternator, regulator, whatever, that died within days of replacing it for a customer, I would be well off. (that said we made money replacing components that had been previously been replaced by a customer and failed. The response was always... "But.. I replaced it a week ago")

Inspect all connections, Check wiring for resistance, confirm good grounds, check voltage at the battery and at the panel volt meter and see if they match, test the panel meter for accuracy, check each component. Assume nothing, and you will find the problem.

So you tested the batteries, found 1 faulty.. Voltages at the battery were OK..

Post everything you tested, how it was tested, in what order, and what were the results?

 

[dlochner]

Prior to my load test/recovery all connections were inspected and confirmed secure. The load test showed battery 1 was failing - so replaced it. Thx

How did you test the battery? Did you do a 20 hour load test or use one of the unreliable capacitance testers?

 

[PlaneTom]

Our 310 has a bum voltmeter in the engine panel, it shows 14.0 volts with just battery power, 15.5 - 16V when the engine is running. The small voltmeter down below at the electrical panel is normal.
Checking at the terminals on the back of the meter with a calibrated DMM shows normal voltage in both cases.
Shopping now for a replacement meter.
The point is, the meter can easily go bad with age, step one is confirm what it is telling you before changing other parts.
Ours isn't an intermittent problem, it's constant.

 

[Tin Kicker]

If replacing a voltmeter, consider changing to a digital display because you really can't tell state of charge with a sweep needle. The difference between 12.7V for a fully charged battery and 60% at 12.2V is somewhere around a needle width for a meter like shown in the OP. Roughly. Perhaps.

The meter at the nav station where the battery test switch is has a narrow needle but accuracy is still a guess so when I replaced it I changed to a digital meter. (The big square old meter simply covers a round hole so just measure the hole diameter before ordering the new small round display.) Then I used the Demo label maker to make a small list from a chart like above and stuck it to the top of the panel. It's a small white font on clear tape so is hardly noticeable along the white line at the top of the breaker panel. When I check the batteries it's now easy to refer the digital number to the label and actually know the state of charge for each battery.

 

[dlochner]

If replacing a voltmeter, consider changing to a digital display because you really can't tell state of charge with a sweep needle. The difference between 12.7V for a fully charged battery and 60% at 12.2V is somewhere around a needle width for a meter like shown in the OP. Roughly. Perhaps.

The meter at the nav station where the battery test switch is has a narrow needle but accuracy is still a guess so when I replaced it I changed to a digital meter. (The big square old meter simply covers a round hole so just measure the hole diameter before ordering the new small round display.) Then I used the Demo label maker to make a small list from a chart like above and stuck it to the top of the panel. It's a small white font on clear tape so is hardly noticeable along the white line at the top of the breaker panel. When I check the batteries it's now easy to refer the digital number to the label and actually know the state of charge for each battery.

Bear in mind the voltage does indicate the SOC, but tells you nothing about the batteries capacity. An old battery that has lost much of its capacity can still have voltage readings indicating it is fully charged, it will be fully charged but may have only a small portion of its initial capacity, amphours, left.

 

[Tin Kicker]

Of course.