replacing amp gauge with volt gauge ?

[gulfvet]

got a new set of gauges for my 1978 sea sprite and the install went well except for the volt gauge. wired the volt gauge like the old amp gauge was wired and nothing, motor wont turn over and no acc. work. wired the amp gauge back in, and all is well. My question is what is the difference in the way the volt gauge is wired vs. how the amp gauge is wired. The leads on that were connected to the amp gauge are.....one from the ign.switch,orange lead and red lead from the harness. My boat uses the motorola alternator,i think this is where the orange lead is coming from,but not sure. any help would ne appreciated. Thanks.

 

[GA_Boater]

Re: replaceing amp gauge with volt gauge ?

Re: replaceing amp gauge with volt gauge ?

You can't replace an ammeter with a voltmeter with wiring changes. An ammeter measures current (amps) while the voltmeter measures .. er um, volts. Wire the voltmeter to switched 12 volts. It should work as long as your first try didn't blow-up the voltmeter.

The ammeter shows current charge/discharge. In other words, all battery loads (except for the starter) and alternator charging circuit are through the ammeter. Wiring the voltmeter as a direct replacement for the ammeter may have cooked it.

Hope this all makes sense.

 

[Don S]

Re: replaceing amp gauge with volt gauge ?

Re: replaceing amp gauge with volt gauge ?

What engine and drive combination do you have? There will need to be changes at the engine and at the helm to make the changeover work.

 

[Grandad]

Re: replaceing amp gauge with volt gauge ?

Re: replaceing amp gauge with volt gauge ?

You can't replace an ammeter with a voltmeter with wiring changes. An ammeter measures current (amps) while the voltmeter measures .. er um, volts. Wire the voltmeter to switched 12 volts. It should work as long as your first try didn't blow-up the voltmeter.

The ammeter shows current charge/discharge. In other words, all battery loads (except for the starter) and alternator charging circuit are through the ammeter. Wiring the voltmeter as a direct replacement for the ammeter may have cooked it.

You can't destroy a voltmeter by connecting it incorrectly. It inherently has a high impedance (resistance) to current flow. That's the reason why nothing worked when you installed it where the ammeter was connected before in series with all your loads. The ammeter has a low resistance so that it does not significantly impede the flow of current, only measures it. A voltmeter is intended to be connected directly in parallel with the 12 volt supply, so it must have a high resistance to current flow for it to survive. - Grandad

 

[Don S]

Re: replaceing amp gauge with volt gauge ?

Re: replaceing amp gauge with volt gauge ?

You can't destroy a voltmeter by connecting it incorrectly.

Put a volt meter in place of an ammeter by just hooking up the two wires going to the ammeter directly to the two terminals on a voltmeter and let me know how well the voltmeter works after you find the engine won't start.

 

[dennis461]

Re: replaceing amp gauge with volt gauge ?

Re: replaceing amp gauge with volt gauge ?

You can't destroy a voltmeter by connecting it incorrectly...... - Grandad

I can

Dennis Schiller P.E.
Hope Creek System Engineering
Public Service Electric and Gas
Hancocks Bridge, NJ

 

[Silvertip]

Re: replaceing amp gauge with volt gauge ?

Re: replaceing amp gauge with volt gauge ?

Didn't we just cover all of this in a post earlier today???????????????????????????

 

[Grandad]

Re: replaceing amp gauge with volt gauge ?

Re: replaceing amp gauge with volt gauge ?

Put a volt meter in place of an ammeter by just hooking up the two wires going to the ammeter directly to the two terminals on a voltmeter and let me know how well the voltmeter works after you find the engine won't start.

Don, The voltmeter, the engine and and anything else downstream of the voltmeter won't function, but the voltmeter won't be broken. It just won't work properly in that configuration.- Grandad

 

[Grandad]

Re: replaceing amp gauge with volt gauge ?

Re: replaceing amp gauge with volt gauge ?

I can

Dennis Schiller P.E.
Hope Creek System Engineering
Public Service Electric and Gas
Hancocks Bridge, NJ

Dennis - I suppose you could reverse the polarity and possibly bend the needle, but unlikely. Or you might connect to high voltage off your spark circuit. Otherwise you can't hurt it with 12 volts. Grandad

 

[gulfvet]

Re: replaceing amp gauge with volt gauge ?

Re: replaceing amp gauge with volt gauge ?

It is a mercruiser 898 w/motorola alternator. but after reading all the replys, i think i will stick with the amp gauge, Thanks for all the info people.