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I have a triple gauge but have not wired up the voltmeter. It will have a ground, but where do I hook the positive? Somewhere on the alternator?
Thanks
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it will do the job hooked up to a switched hot wire at the ignition switch, which will be more convienent than running the wire all the way back into the engine compartment.
Z.
'66 Galaxie 500
'65 K code Mustang
Last edited by zray (January 20, 2013 10:50 pm)
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zray wrote:
it will do the job hooked up to a switched hot wire at the ignition switch, which will be more convienent than running the wire all the way back into the engine compartment.
Z.
'66 Galaxie 500
'65 K code Mustang
Please don't think I'm being argumentative. I need an education on auto electronics. I'm thinking that a properly functioning alternator supplies around 14V to the battery and keeps it charged. Whereas a properly functioning voltage regulator allows current drawing devices such as instruments and bulbs to draw and even 12V with very little fluctuation. I want my voltmeter to tell me if my alternator is not charging the battery. If I hook it up to an ignition switch that draws 12V, I will still see the 12V being drawn from the battery, even if the alternator is bad. Am I correct?
Last edited by Jayz66 (January 21, 2013 3:14 pm)
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no you are not correct. The ignition switch will get whatever voltage the battery is getting, not just 12 volts. If the aternator & regulator are working correctly, the battery voltage will never drop below 12.7 - 12.9. And thats the voltage your voltmeter will show if you put it either directly on the battery, or on the switched hot post of the ignition switch. Your regulator will regulate the alternator output to 12.9 to 14.5 volts depending on the system needs. For example, if you have to crank the engine for a while before it starts, the voltage will show 14+ volts for a while after the car starts until the battery gets back to 100%, after which the voltage will drop down to 12.9 or so.
Z.
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OK, like I said, I need an education in automotive electronics. I remember a Camaro I had that kept burning up headlights. All I remember is that the voltage reg was bad (correct or not, that's what I remember). Come to think of it, I recently learned that newer alternators have internal voltage regs, so now it makes sense for that too.
That brings up a question. For instance, if my alternator goes bad, what will my voltage reg show?
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Hey Z, thanks for that straightforward explanation. Wiring is not one of my strengths also, I appreciate stuff explained that is easy to understand the way you did.
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to clarify, the voltmeter, placed on any switched hot lead, will show whatever REGULATED VOLTAGE the battery is getting. The regulated voltage will very from 12.7 - 12.9 on the low end, and as high as 14.5+ if the battery is low for any reason. Your regulator does not keep the ignition, lights, etc from getting more than exactly 12 volts. These parts function fine with voltages from 12.7 to 14.5 which is what the regulator allows to pass from the alternator to the battery. I'm not an engineer, so my descriptions are not very consise, just based on pracical experience. when I'm not under the hood of an old Ford I'm at work fixing motorcycles.
Z.
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Z, Sorry I forgot, but I shoulda said thanks for the explanation. I appreciate it.
What about my other question?
That brings up a question. For instance, if my alternator goes bad, what will my voltage reg show?
I guess it will tell me if voltage is too high or low if my VOLTAGE REG goes bad, or if my battery is beginning to drain? Did I get it right this time?
Last edited by Jayz66 (January 21, 2013 6:37 pm)
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if alternator is bad, the charging light should come on. If you have a voltage gauge, then it won't show normal back and forth movement, only a steady decline. you can go quite a ways on battery power alone IF the lights are off.
Z.
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Jay also keep in mind that your gauge will fluctuate based on draw. In other words if you fire the car up and all accessories are off it will show a higher voltage, then turn on your lights, heater blower, stereo, and any other accessories you have on and the voltage will drop. Have you ever sean an old car with original alternator and a loud stereo system at night??? every time the music thumps the headlights will dim because the draw of the stereo amp is lowering the over all voltage in the system, dimming the lights.
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