correct gauge application

[monk-monk]

i have a '72 1150 Merc outboard and im wondering what the difference is between a "battery" gauge that monitors Voltage and an "ammeter" gauge? is the ammeter only for "Alternator" equipped engines or will it work with this 1150's magnito charging system?

 

[mthieme]

Re: correct gauge application

An ammeter measures amperage...or speaking loosely - the rate of charge.
An ammeter will work with a magneto.

 

[monk-monk]

Re: correct gauge application

thanks mthieme, SO... with that in mind, which way would you prefer to monitor battery charge, plain battery voltage or amp input to battery...it seems logical to me that the amp input would be a more accurate reading of just what and how much charge is going to the battery! Your thoughts?

 

[Chris1956]

Re: correct gauge application

An ammeter will show if the battery is being discharged or charged. They read -30A to +30A. They are wired in series with the alternator. You would need to pull two heavy wires from the rectifier to the ammeter and back, to hook one up.

A voltmeter shows the battery voltage. If the battery reads 12.5-13V or more it is being charged. If it reads less than 12V it is being discharged. You may connect a voltmeter to the thin wire that runs your tach and gas gauge.

From a practical standpoint, the voltmeter is the best thing to have. You can determine if the motor is charging by looking at it. You cannot tell the rate of charge however.

BTW - your motor doesn't charge very much anyway (<10A at WOT)