Ammeter or Volt meter question?
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Drifting
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From: Dandridge TN
Ammeter or Volt meter question?
Do 69's have ammeters or volt meters for the gauge? My gauge reads -14 to +14 and it stays between 0 and +14 all the time with the car off and while its running and I don't see any movement, is this normal? I checked the charging with my hand held volt meter at the battery and every thing seems is normal. I may have a faulty gauge.
Drifting
Joined: Oct 2001
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From: Westampton NJ
Re: Ammeter or Volt meter question? (Steve Adkins)
A 1969 should have an ammeter, marked -40 to +40. It should point to the + side until the battery is recharged from starting the car. After that, it should point at 0 for the rest of the drive.
It sounds like you have a voltmeter and if so (and it's wired correctly), it should sit at around 12-14 volts.
It sounds like you have a voltmeter and if so (and it's wired correctly), it should sit at around 12-14 volts.
Melting Slicks
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From: Tucson AZ
Re: Ammeter or Volt meter question? (rainman69)
Based on your guage numbers, you have a voltmeter. In that case, it should read close to the 13 area all the time. (13 volts put out from the battery)
If you had an ammeter, the range would be -40 to +40 and would indicate the rate of charge the battery is receiving and that will vary.
I thought the 69s had ammeters originally.
If you had an ammeter, the range would be -40 to +40 and would indicate the rate of charge the battery is receiving and that will vary.
I thought the 69s had ammeters originally.
Thread Starter
Drifting
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From: Dandridge TN
Re: Ammeter or Volt meter question? (Robert N)
Sorry for my lousy info, you guys are correct, it does read -40 to +40. It stays between 0 and +40 all of the time. It doesn't make a difference if I have every thing on in the car.
Melting Slicks
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From: Tucson AZ
Re: Ammeter or Volt meter question? (Steve Adkins)
Mine reads '0' most of the time. It is rare that it jumps towards +40 and I have only seen it move towards -40 when the starter went and turning the key put a draw on the battery. A good battery will hold its charge.
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Drifting
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From: Dandridge TN
Re: Ammeter or Volt meter question? (Robert N)
Mine reads '0' most of the time. It is rare that it jumps towards +40 and I have only seen it move towards -40 when the starter went and turning the key put a draw on the battery. A good battery will hold its charge.
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From: Rolla MO
Re: Ammeter or Volt meter question? (Steve Adkins)
A quick test is to turn the car off and leave your headlights on... then if you have an ammeter it should go left of zero (to the negative side) to indicate that the battery is discharging. If it stays positive, around 12-13 volts, then you have a voltmeter.
Hank
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From: Virginia USA
Re: Ammeter or Volt meter question? (rollavette71)
If you have the ammeter and it says that your alternator is charging the battery all the time (needle above the 0 mark all the time) then the first thing I’d check is the battery ground cable at both ends. Clean it up and make sure it has a good connection to the battery and the frame. Then check the engine block to frame ground connection; again it should have good contact to the block and frame. I had a similar problem with my 71 and this cured it. It is normal for you needle to jump to the + side a bit when you turn on electrical stuff in the car. Take a look at your needle when your turn signals are flashing and you'll see what I mean. Hope this helps.
John
:thumbs:
[Modified by theandies, 9:40 AM 2/18/2003]
John
:thumbs:
[Modified by theandies, 9:40 AM 2/18/2003]
Thread Starter
Drifting
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From: Dandridge TN
Re: Ammeter or Volt meter question? (theandies)
Thanks John, I will check the grounds when I get home. The thing that has me puzzeled is when I turn the lights on or when I push the brake pedal the gauge does not move. :confused:
Pro
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From: Morinville Alberta
Re: Ammeter or Volt meter question? (Steve Adkins)
While we are on this topic maybe you guys can help me out.
I am installing new gauges in my car and replacing the ampmeter with a voltmeter. Can I just connect the two leads that went to the ampmeter and tap off this connection for the voltmeter or should I wire it different.
Thanks.
:steering:
I am installing new gauges in my car and replacing the ampmeter with a voltmeter. Can I just connect the two leads that went to the ampmeter and tap off this connection for the voltmeter or should I wire it different.
Thanks.
:steering:
Safety Car
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From: South Central Louisiana
St. Jude Contributor
Re: Ammeter or Volt meter question? (theandies)
If you have the ammeter and it says that your alternator is charging the battery all the time (needle above the 0 mark all the time) then the first thing I’d check is the battery ground cable at both ends. Clean it up and make sure it has a good connection to the battery and the frame. Then check the engine block to frame ground connection; again it should have good contact to the block and frame. I had a similar problem with my 71 and this cured it. It is normal for you needle to jump to the + side a bit when you turn on electrical stuff in the car. Take a look at your needle when your turn signals are flashing and you'll see what I mean. Hope this helps.
John
:thumbs:
[Modified by theandies, 9:40 AM 2/18/2003]
John
:thumbs:
[Modified by theandies, 9:40 AM 2/18/2003]
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Re: Ammeter or Volt meter question? (71,454,4spd)
When you first start your car, you use the starter which is the single biggest draw your battery faces. After starting, your voltage reg. should put your alternator into the high charge rate. You should see max + amp reading for the first couple of minutes. After a few minutes the amp reading should drop back close to zero. Most factory ammeters are not particularly accurate near zero. The needle may show 1-2 amps discharge or 1-2 amps charge at low charge levels. That is why you want to check your charging circuit right after start up when the v.r. is calling for high charge rate. If you have a volt-ohm meter you can also check your battery voltage before start up, then check it again with the engine running. Before starting the car, it should read between 12.5-13.5 volts. With the engine running you should get a voltage reading of 13.5-14.5, but it should be higher with the car running. If the off voltage read 12.5, then 13.5 with the engine running is ok. If you had a 13.5 reading with the engine off, you want to see 14-14.5 with the engine running after a few minutes of run time.
Thread Starter
Drifting
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From: Dandridge TN
Re: Ammeter or Volt meter question? (theandies)
Let me know how it turns out.
John
John
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From: Niedernhausen, Germany
Re: Ammeter or Volt meter question? (Steve Adkins)
Steve,
these Ammeter tend to break a lot. As a matter of fact, I checked mine (it is easily possible to open it by bending some sheet metal tabs of the housing) and found a little (hair-thick) copper wire melted. Took me half an hour to get it soldered (well, I am not too good at soldering) and the thing worked OK.
BTW, these Ammeters actually measure a voltage and by a calibrated resistor they convert that into Amps - that's what car developers also do when they analyze an eletctrical system in a new car: They install big, calibrated resistors (called 'shunts') e.g. parallel to the line between alternator and battery and convert the volt-reading in amps. This way, they do not have to cut into wiring harnesses (as they would have to to measure amps directly). Of course it is also far less expensive to run two tiny wires to a indirect ammeter rather than to install a real one with heavy gauge wire.
The amp-number itself is not so important anyway, but the direction in which the current runs (indicating wether the alternator charges or current is drawn from the battery) is what that guage is for.
Regards,
Thomas
these Ammeter tend to break a lot. As a matter of fact, I checked mine (it is easily possible to open it by bending some sheet metal tabs of the housing) and found a little (hair-thick) copper wire melted. Took me half an hour to get it soldered (well, I am not too good at soldering) and the thing worked OK.
BTW, these Ammeters actually measure a voltage and by a calibrated resistor they convert that into Amps - that's what car developers also do when they analyze an eletctrical system in a new car: They install big, calibrated resistors (called 'shunts') e.g. parallel to the line between alternator and battery and convert the volt-reading in amps. This way, they do not have to cut into wiring harnesses (as they would have to to measure amps directly). Of course it is also far less expensive to run two tiny wires to a indirect ammeter rather than to install a real one with heavy gauge wire.
The amp-number itself is not so important anyway, but the direction in which the current runs (indicating wether the alternator charges or current is drawn from the battery) is what that guage is for.
Regards,
Thomas
