Carnut67
Senior Member
Posts: 551
Loc: Tyler, Texas
Reg: 06-03-03
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08-05-12 02:02 PM - Post#2256062
67 Camaro with stock factory guage package. I dont understand electrical systems so need to know if I have a problem. My ammeter guage reads about 3/4 during normal driving conditions, but when I stop at idle it reads around 1/2. I dont recall it reading so high in the past. Is it showing a problem?
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 acardon
"9th Year" Silver Supporting Member
Posts: 9454
Loc: DFW TEXAS
Reg: 03-25-05
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08-05-12 02:17 PM - Post#2256069
In response to Carnut67
The condition of the battery can affect the output of the alternator. Do you have an electric fan? It could be coming on more than usual, calling for more output from the alternator.
Don
66 Corvair (driving)
57 2dr HT (restoring)
56 2dr HT (waiting to be restored)
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bobb
Super Senior Member
Posts: 4626
Loc: paradise
Reg: 09-05-03
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08-05-12 05:00 PM - Post#2256132
In response to Carnut67
i would get a volt meter and see what comes out of it. it could be a dozen things. volts at the battery while running should be no lower than 13.8 in my book. some books say 13.6. fast idle should not be above 14.4. these numbers will differ with the amount of amps flowing. higher amps-lower volts. lower amps higher volts. i like my amp meter hooked up only to the battery so i know what the battery is getting. clean battery connections and good cables are mandatory for good electrical performance. got pics?
| 70 L camino 350 all forged,174 baby blower, g-force 5 spd, road rage suspension. Pray first before all else fails. |
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 Vaughn
"11th Year" Gold Supporting Member
Posts: 13553
Loc: Colorado Springs, CO
Reg: 08-08-04
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08-08-12 07:26 PM - Post#2257317
In response to bobb
If it is drawing that much current, you have a short somewhere. Even fans won't draw that much current. You need to find the short and fix it - assuming that the gauge is reading right.
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65_Impala
Very Senior Member
Posts: 1593
Reg: 12-29-02
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08-10-12 05:42 PM - Post#2257960
In response to Carnut67
Ammeters actually measure voltage, not current. I believe most if not all factory GM ammeters measure the voltage across part of the wire coming from the battery to the horn relay and then to the firewall. I'm not sure where the 2 wires connected exactly, maybe the horn relay and a terminal by the battery? At any rate, if that wiring is developing a poor connection you can get a higher voltage drop which would cause a higher reading on the ammeter.
Other ammeters (aftermarket) measure the voltage across a shunt resistor on the back of the meter. They could show a higher reading if the shunt is having issues or suffering a bad connection.
Overall, this measure voltage drop and display it as current is one of the reasons ammeters aren't as good as voltmeters.
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