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I would like to know how much deflection of the needle is normally indicated.

I have a new gauge that I connected one lead to the battery and the other to the horn relay. When the battery is being at charged at 14.5 volts, the needle barely moves off of the center mark. I turned on the headlights and fan to load the system to force more alternator output, but no real change. When starting the the engine, the needle drops about a quarter of the discharge portion of the scale.

Do you see half of the full charging range, more, or less when the engine is running?

It acts the same as the gauge already in the dash, which I thought was bad.

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Brian TC#1092, ACES#4374
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1964 Malibu SS Convertible (Garage Queen) Before Restoration
1965 El Camino (Daily Driver) Before Restoration
1981 Corvette (Sidelined for repairs)
 

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Brian,
If the battery is good & is already pretty well charged, you won't see much charge side deflection of the meter when the engine is running. The ampmeter measures current into (charging) & out(discharge) of the battery.

If everything is working correctly, what I would expect to see is very noticable deflection while cranking. Then after the engine starts, you'll see some very short lived charging deflection. Once the battery has been "rejuiced" from the agony of cranking the engine, there will not be hardly any draw from or charge to the battery while running.

If the alternator & regulator are working properly, most all of the juice to run the car's electrics will come from that. The battery acts more like a capacitor while the engine is running, filtering and only augmenting the power from the alternator when quick, high current demand items are enabled (i.e. horn). You still won't see much activity on the ampmeter though.

Phil

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Phil Wise
67 SS Convertible
(now on the down slope of the resto curve)
ACES # 834, TC # 231
Photos of a work in progress

[This message has been edited by Phil Wise (edited 11-16-2001).]
 

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Phil's right Brian! You won't see very much needle movement on a properly charged system. If I put my hi-beams on and turn the flashers on (without the car running) my needle moves about 1/8" into the discharge side of the gauge. If I haven't started the car for a while it only shows slightly into the charge side for a very short time, then mostly remains in the center of the gauge while running. Mike, M22
 
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