Any reason to use a vintage ammeter?

[Marco Flamingo]

My prior owner put in a nice 100A Balmer alternator with an external regulator. I just put in a battery monitor that shows in/out down to 100ths of an amp. PO put in all new engine gauges except for the original 60A analog ammeters at both helms. The originals were then too small, kind of crusty looking, and didn't match, so I bought new 100A gauges.

The install seems pretty straight forward. The PO had disconnected the lead to the alternator and simply wrapped the connector with electrical tape. But in looking at how the old-school analog gauges work, I'm not sure about connecting my new gauges. The original gauges still have the hot from the house connected. My understanding is that I will have a hot, fairly large gauge wire running around the boat up to the gauges all so that I can see a little needled move if I'm not charging.

My concern is that I already have a more accurate ammeter that doesn't require the house feed current to run all over the boat (but it can't be seen from the flying bridge). Maybe just install the new gauges for cosmetic reasons and don't connect them? Pull out the hot wire that is there and does nothing? That's the plan unless there is some good reason to have an analog gauge.

 

[High Wire]

Do you have a voltmeter at the helm? If not I would suggest adding a digital readout there and leave the not-heavy-enough ammeter wire disconnected. A decent voltmeter will tell you big picture what's going on with your alternator with a simple glance.

 

[catalinajack]

Many folks similarity situated replace those 60-amp ammeters with voltmeters. If you choose to do that, be certain to wire them directly to your battery bank for an accurate reading.

My prior owner put in a nice 100A Balmer alternator with an external regulator. I just put in a battery monitor that shows in/out down to 100ths of an amp. PO put in all new engine gauges except for the original 60A analog ammeters at both helms. The originals were then too small, kind of crusty looking, and didn't match, so I bought new 100A gauges.

The install seems pretty straight forward. The PO had disconnected the lead to the alternator and simply wrapped the connector with electrical tape. But in looking at how the old-school analog gauges work, I'm not sure about connecting my new gauges. The original gauges still have the hot from the house connected. My understanding is that I will have a hot, fairly large gauge wire running around the boat up to the gauges all so that I can see a little needled move if I'm not charging.

My concern is that I already have a more accurate ammeter that doesn't require the house feed current to run all over the boat (but it can't be seen from the flying bridge). Maybe just install the new gauges for cosmetic reasons and don't connect them? Pull out the hot wire that is there and does nothing? That's the plan unless there is some good reason to have an analog gauge.

 

[Comodave]

I would get rid of those old style ammeters. No way I would run that big a cable up to the helm and back, too much voltage loss and potential for a short with a large current carrying cable. If you want an ammeter then go with a shunt type. Small wires to bridge and no voltage loss and also the potential for shorting of a large current carrying cable is gone. No down sides just upsides.

 

[CharlieJ]

I am fairly certain that analog ammeters up to 50A have internal shunts.

100A meters require an external shunt in the B+ conductor. Small gauge wire, shunt high and shunt low, are then routed to the meter at the helm.

You might want to check before proceeding.

 

[Marco Flamingo]

No way I would run that big a cable up to the helm and back, too much voltage loss and potential for a short with a large current carrying cable. If you want an ammeter then go with a shunt type.

That's sort of what I was thinking. My new ammeters are not the shunt style. Neither were the originals. Which brings up another problem that I hadn't thought about. The 6 gauge wire was enough for the 50A ammeter but not for the new 100A meters. Looks like I may install them just for cosmetics. Beats the ugly old ones or an empty 2 inch hole. But I could have bought these voltage meters to match the other gauges.

My new battery monitor also has a very accurate voltage readout, but it's not in the instrument cluster. It's by the circuit panel a few feet away.

 

[FF]

A good digital Volt meter at the instrument panel connected to the starter motor has many uses.

On cranking the engine start seeing at least 9.5V assures the diesel engine should spin fast enough to fire off.

A glance will show if the alt. is operating and watching the Voltage climb to 14+ volts then eventually drop back that the V regulator is working.

 

[Nomad Willy]

The young bucks have a saying TMI that applies here.

As long as you’ve got the information you need why use anything else? The answer is that there may be things you should know that you don’t know .. as in post #7 by FF.

But of course if you’ve got a 1952 CC bull nosed Cruiser that’s mint you probably think the quivering needle thing is good enough.

I like digital when seeing a slow change is important. Whereas a fuel tank gauge the approximate reading is good. Any more is TMI.

 

[bglad]

Last full current ammeter setup I saw on a Defever 44 was turning 14.7 volt alternator output into 12.2 at the batteries. Too long a run and too many series connections for a low voltage circuit. Best to run alternator charge current shortest path possible to batteries.

My prior owner put in a nice 100A Balmer alternator with an external regulator. I just put in a battery monitor that shows in/out down to 100ths of an amp. PO put in all new engine gauges except for the original 60A analog ammeters at both helms. The originals were then too small, kind of crusty looking, and didn't match, so I bought new 100A gauges.

The install seems pretty straight forward. The PO had disconnected the lead to the alternator and simply wrapped the connector with electrical tape. But in looking at how the old-school analog gauges work, I'm not sure about connecting my new gauges. The original gauges still have the hot from the house connected. My understanding is that I will have a hot, fairly large gauge wire running around the boat up to the gauges all so that I can see a little needled move if I'm not charging.

My concern is that I already have a more accurate ammeter that doesn't require the house feed current to run all over the boat (but it can't be seen from the flying bridge). Maybe just install the new gauges for cosmetic reasons and don't connect them? Pull out the hot wire that is there and does nothing? That's the plan unless there is some good reason to have an analog gauge.

 

[bayview]

i dont see any reason for ammeters. The voltage readings tell you all you need.

 

[psneeld]

i dont see any reason for ammeters. The voltage readings tell you all you need.

I think there is some further discussion that others may not agree with that.

Some power sources register voltage, yet are pushing almost no amps.

Dash ammeters...... to that I will agree though.

 

[Nomad Willy]

bayview,
I hadn’t thought about it but I think you’re right.