Ammeter wiring revisited

[interalian]

My very over-gauged boat has a +/-15A ammeter on the dash. Whoever originally wired it only wired accessory loads to it, so it's essentially useless as it only shows discharge when the running lights or lighter are in use and never charge. I'm going to re-wire it so it shows whether or not the alternator is charging.

Since it's only a 9A alternator (or is it 6?), I'm going to lift the red rectifier wire off the terminal block, run it to the gauge, and run a wire back to the terminal block to complete the circuit. That way I'll know if and how much the thing is charging. #14 wire should be plenty but that cheap #12 stuff you can get for outdoor lighting might be better as it's paired.

This will be part of my hard water (winter) project along with full re-wire and a proper fuse panel for all the accessories.

Idle hands and all that...

 

[jakedaawg]

Never mind

 

[jakedaawg]

Never mind

 

[Chris1956]

Obviously you will not want the wire to short to ground. You might put it into some plastic sleeve to protect it's insulation.

 

[interalian]

Obviously you will not want the wire to short to ground. You might put it into some plastic sleeve to protect it's insulation.

Indeed. Combine a positive indicator for charge with the voltmeter and I'll have a gauge that actually means something. I'd once considered running the entire load circuit the same way, but changed my mind. Who knows, it may change again.

 

[gm280]

I would not use a zip cord type wire for that, and here is why. The typical low voltage wire you are referencing is not tinned wire. It will not hold up under typical marine applications. I would forgo that type wire and buy some quality 10 gauge that is marine certified. That way you are covered in the current situation and the tinned wire will hold up a lot longer to a boating environment. But that is just me!

 

[interalian]

Good idea. But I'd only worry about non-tinned wires if the boat was ever going to the salt again, and since OMC used non-tinned wires on the TnT power and gauge leads they set the precedent.

 

[Chris1956]

Of course, if you just used a simple voltmeter in the dash, and the voltage was 12.5VDC+, the alternator is charging. But it doesn't tell you how much..

 

[interalian]

I have a voltmeter on the dash too. Dad went a bit overboard when setting this boat up. I have temp, water pressure, tach, speedo, volts and ammeter. Gauge setup more in line with a small ocean liner than a 16' runabout.

 

[gm280]

I have a voltmeter on the dash too. Dad went a bit overboard when setting this boat up. I have temp, water pressure, tach, speedo, volts and ammeter. Gauge setup more in line with a small ocean liner than a 16' runabout.

Yea, I have to admit, my first Bass Boat, I wanted gauges everywhere. You know, eye candy. But after the newness wore off, most of the gauges were rarely looked at much. I learned from that lesson. The bare minimum will always be the better choice and least possible worries about wiring and/or gauge failures as well. JMHO

 

[interalian]

Agreed but since I already have all the gauges and holes in the dash they might as well work. Really though, I'd consider this as a minimum complement:

Tach
Temp
Pressure
Volts

If I could scrounge up a matching gauge, I'd put two temp gauges in and ditch the ammeter. But realistically, where am I going to find a 1983 vintage OMC temp gauge?

 

[Derrick Fronckowiak]

interalian, these older ammeters require a very large gage wire run to them, right? I mean doesn't the entire charging current go through them? My understanding is the newer ones are scaled and use a shunt near the source (alternator and battery) so you can run much smaller gage wires through the boat, up through the console and into the ammeter (a safety, reliability and practicality thing). Of course if you are trying to stick with the old original gages there may not be a work around. Am I off on this?

 

[interalian]

No, you're spot on. The gauge takes the full current and the shunt is inside it. I'm not concerned about running it this way.

 

[oldboat1]

A low brow alternative is one of those state-of-charge meters hooked up to the battery. Even with low amp alternators, I find they move up solidly into the fully charged range if the system is working. My batteries don't usually show that at rest, unless I've just finished with a charger and they still show a flash charge.