[RC 70]

I started my 70 SS LS5 tonight for the first time in 8 months. During the resto process I converted from idiot lights to full gauges and was wondering what the amp gauge should read? It is reading below 40, or in the negative. Does this mean my alternator isn't charging my battery?

 

[Steve S]

You shouldn't be reading negative 40 amps just idling so I suspect you have the wires to the amp gauge backwards and it is actually charging. Especially if the current increases with throttle then falls off at idle. Did the amp gauge ever work right?

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Steve Strasemeier (70SS 396, Fathom Blue/White Stripes)
My 70SS

 

[RC 70]

I don't know if the gauge worked right or not. I bought the restored gauge set from a CA supplier and just put them in the car.
Which wires are you talking about?

 

[RC 70]

Wait a minute. If I have a 37 amp alternator, wouldn't it read 37 amps or just below or to the left of 40 on my amp gauge?

What does everybody elses amp gauges read on a 70 BB?

 

[John_Muha]

<BLOCKQUOTE>quote:</font><HR>Originally posted by RC 70:
Wait a minute. If I have a 37 amp alternator, wouldn't it read 37 amps or just below or to the left of 40 on my amp gauge?

What does everybody elses amp gauges read on a 70 BB?<HR></BLOCKQUOTE>
RC
Sounds like you are mistaking amps for volts. A lot of people do. Volts are considered "pressure" while amps are the amount. Voltage should stay the same while amperage goes up and down, depending on what the car needs.
If you really have a 37 amp alternator (yours is bigger than that) and the car wants 37 amps to runs, the alternator would be too small. You always want an alternator bigger than what you need.
Confusing things a little is that a lot of car amp meters are really volt meters, even though they say amps on them. They don't really measure amps that the car wants. They only show an indication that the voltage is going up. When the car is off you measure 12 volts from the battery. When the alternator is working, now you are reading higher, around 14.75 volts, so the meter goes up. Maybe that helped?

 

[m22chevy]

A properly charged battery in a car running with no major load should be reading around zero. If you left your lights on (by mistake of course) for a couple of hours and were able to start your car you would see the amp gauge indicating a + amps reading telling you that it is trying to bring the battery voltage back up to snuff! Turn your lights on with the car off and you should see the amp gauge indicating - amps. Hard to say what the exact amp readings should be but typically you don't see much of an amp swing with a good battery and good charging system.

 

[jlone]

im not sure what the problem could be but mine reads zero..then when the car is off it goes a little into the - area..at first i thought 0 was bad..i guess i was wrong

 

[DaveK]

Jlone,

Mine reads the same way. I can barely see the needle deflect either way ... but if you look close it does move. I thought something could be wrong with the meter but I tested it with a ohm meter and it checks out ok.

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Dave Knapp
TC #388
ACES #3474
SCCCC #310
'70 SS 396
L34

 

[RC 70]

Boy, some people (Me). I checked my gauge yesterday and it reads just to the left of zero, or in the negative with the car running. Is this OK.

 

[m22chevy]

Running in the negative with the engine running would be showing a discharge condition on your battery! Maybe your wires on the amp gauge are backwards! Try turning on all your lights with the car off and you should see a negative reading.
Mike M22