 Amp meter vs Volt meter, Which one to use? |
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| nola914 |
 Jun 28 2007, 10:26 PM
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Member  Group: Members Posts: 77 Joined: 19-January 06 From: New Orleans, LA Member No.: 5,440  |
I'm close to starting up my 2.0L out-of-body. I'm going to plug in a few basic guages to keep an eye on what's going on. In my parts bin I have an old Amp meter (old - but never been used). But I got to thinking... the 914's use a volt meter, as do newer cars. I suppose that there is a reason for that.
Seems to me, and this is a very simplified way of looking at it, the amp meter is providing info about the alternator's operating efficency, while a voltmeter is showing the battery's condition. Am I thinking correctly? In my case, with a new battery, but an old alternator that hasn't been turned in 4 years, to get a reading on the system, should I use the amp meter or look around for a volt meter? Or both? |
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| marks914 |
Jun 29 2007, 10:33 AM
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Senior Member Group: Members Posts: 845 Joined: 9-October 04 From: the motor city Member No.: 2,912 Region Association: None |
I prefer the voltmeter, but I would get one of these
mark (IMG:http://inlinethumb06.webshots.com/4997/2831499580057582025S500x500Q85.jpg) |
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| skips |
Jun 29 2007, 09:25 PM
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#3
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Newbie Group: Members Posts: 7 Joined: 20-May 06 Member No.: 6,035 |
You can use an ammeter "shunt" to use an ammeter without using big wires to the meter, shunt and meter need to be a matched set. Google experimental aircraft electric systems, lots of discussions on preference of voltmeter vs. ammeter.
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| Bartlett 914 |
Jun 30 2007, 10:05 AM
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#4
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Advanced Member Group: Members Posts: 2,216 Joined: 30-August 05 From: South Elgin IL Member No.: 4,707 Region Association: Upper MidWest |
QUOTE(skips @ Jun 29 2007, 07:25 PM)  You can use an ammeter "shunt" to use an ammeter without using big wires to the meter, shunt and meter need to be a matched set. Google experimental aircraft electric systems, lots of discussions on preference of voltmeter vs. ammeter. (IMG:style_emoticons/default/agree.gif) Amp meters work by measuring a voltage across a very small resistor referred to here as a shunt. This resistor is very low in value in ohms and is high in wattage. This can be in the meter or remote mounted. I would never run large wires for this. It would be best using a remote shunt and small wires across the shunt to the volt meter (calibrated to read amps) Not real useful in out cars IMHO. |
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Posts in this topic
nola914 Amp meter vs Volt meter Jun 28 2007, 10:26 PM
SirAndy if you use the amp meter, make sure you use the bi... Jun 28 2007, 10:35 PM chris914 A battery always has a voltage difference that can... Jun 29 2007, 01:53 AM Dave_Darling I think Chris may be overstating things, but he is... Jun 29 2007, 02:35 AM
914-8
The voltmeter gives you an indication of the cur... Jun 29 2007, 10:14 AM Joe Owensby The voltmeter is by far the better instrument. It... Jun 29 2007, 09:46 AM Air_Cooled_Nut
The voltmeter is by far the better instrument. I... Jun 30 2007, 08:27 PM ruddyboys Not to steal this thread, should my volt meter be ... Jun 29 2007, 10:11 AM nola914 Thanks for all of the replys. I was away from the... Jul 2 2007, 08:51 PM |
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