ammeter vs voltmeter

itsaboattime

Senior Chief Petty Officer
Joined
Jul 4, 2007
Messages
791
Hey guys, I have an '83 Johnson 50 horse. I'm wondering if I should install a Voltmeter or an Ammeter to keep track of my charge on my battery. I have a few lights and a stereo installed in addition to my depth finder and running lights. I fish for cats quite often at night and the x-tra light is really handy when landing a big cat. I guess I'm just wondering which will give a more accurate account of how much draw I am putting on my charging system.
 

F_R

Supreme Mariner
Joined
Jul 7, 2006
Messages
28,226
Re: ammeter vs voltmeter

An ammeter, properly installed, will show whether current is being put into or drawn out of the battery at any particular moment.

A voltmeter will show if the overall charge rate is enough to offset the overall draw. In other words, if the voltmeter reads higher with the motor running than it does with the motor stopped, you are putting more juice into the battery than you are drawing out.

Neither one will show the state of the battery (full charge, half charge, etc.) Before somebody yells at me, I am speaking of a common dash-mount voltmeter which is far from being precise enough.
 

itsaboattime

Senior Chief Petty Officer
Joined
Jul 4, 2007
Messages
791
Re: ammeter vs voltmeter

I'm just speaking of an in dash myself. all I need to know is if I am pulling more than I'm putting into the battery and by how much.
 

kenmyfam

Supreme Mariner
Joined
Aug 10, 2006
Messages
14,392
Re: ammeter vs voltmeter

Theres nothing quite like the warm and fuzzy feeling of 2 batteries or one of those booster packs on board either.
 

ebry710

Ensign
Joined
Jan 29, 2008
Messages
981
Re: ammeter vs voltmeter

An ammeter, properly installed, will show whether current is being put into or drawn out of the battery at any particular moment.

A voltmeter will show if the overall charge rate is enough to offset the overall draw. In other words, if the voltmeter reads higher with the motor running than it does with the motor stopped, you are putting more juice into the battery than you are drawing out.

Neither one will show the state of the battery (full charge, half charge, etc.) Before somebody yells at me, I am speaking of a common dash-mount voltmeter which is far from being precise enough.

I like both on the dash.

The amp meter I used for the charging system with the engine is on and battery discharging when the engine is off.

The voltmeter tells me power in the system. If engine is running I will monitor how high and how steady the voltage. When the engine is off I will monitor how the battery maintains that voltage.
 
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