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On our trip this past week, while I was scrolling thru the info center, I noticed the amps was reading 13.5. Other times it was up around 14.5.
Do these cars have a system to cut the amps down to save "energy"?
 

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The Bacon Hauler (‘12 Cop Charger)
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The charging system’s voltage regulation duties are handled by the PCM, which uses inputs from various sensors to make sure the alternator is only putting out enough volts to cover car’s electrical needs and also keep the battery charged.

This keeps the load that the alternator is under to the absolute minimum at all times (while still meeting car’s needs), thereby preventing the alternator from wearing out prematurely. It also reduces the amount of parasitic loss the charging system inflicts upon the engine’s output, which is helpful for MPGs and such.

That is my understanding of it all anyway...
 

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Mine almost always reports 14.0v-14.1v - at least with the headlights off. When the headlights are on, I think it usually reports 13.8v-13.9v....

Also - the value reported is volts, not amps. Just FYI.
 

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The Bacon Hauler (‘12 Cop Charger)
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Mine almost always reports 14.0v-14.1v - at least with the headlights off. When the headlights are on, I think it usually reports 13.8v-13.9v....

Also - the value reported is volts, not amps. Just FYI.
Pop Quiz: Given the voltage drop you just noted, do you know how to quickly calculate the amperage draw of the headlights being operated?

Hint: if you know how to calculate the true RMS wattage capability of a given amplifier, you can do this....

Tick tock ! What’s your answer?!?
 

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The Bacon Hauler (‘12 Cop Charger)
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Oh man you get to learn a helli-useful piece of math today then...useful for audio upgrades mostly, but still.

Commit this formula to memory:
Volts x Amps == Watts

Now let's say your friend just bought a nice 1200w Crunch amp to push those two old Sony X-plod subs you gave him. The subs need a total of 800w RMS to really sing, but your buddy can't get them to sound good. It's almost as if they aren't getting enough power, but that can't be with an amp that says it delivers 1200w, can it?

Never trust the advertised numbers! Verify for yourself.

Add up all the amp's onboard fuses' amperage ratings, and that is your total Amps number for above equation. (Assume amp has one 25A fuse onboard).

You already know the Volts number - it's the same for every car (pretty much): 14.4.

14.4 x 25 == 360

There you go, the subs need 800w, but the amp cannot possibly deliver even 50% of their RMS wattage. Air go, will sound like crappola.

Now that's a simplified method for estimating max output. In reality you should use 13.8 or 13.4 for volts and multiply the final watts by another fraction dependent upon amp class to get REAL max wattage possible.

But those extra steps aren't necessary to mess with when you're just trying to figure out the true capabilities of an amp that has been falsely advertised to put out more power than it possibly can.


Now, given all that, it should be easy to calculate amps that headlights are pulling, right?

Assume you have the standard 55w/65w halogen headlamps, and they cause a 0.2v - 0.3v voltage drop when operated like you noted. So about how many amps are the two bulbs pulling when you turn them on (low beam versus high; always only 2 at a time)?

(if you get it right, you can have all the beers in my cooler right now!)
 

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The Bacon Hauler (‘12 Cop Charger)
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you better hurry if you want to win my beer...there ain't but one left


WP_20190720_18_59_25_Pro.jpg WP_20190720_18_55_18_Pro.jpg
 

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on my '16 - every certain # of Key On, Engine Running cycles (can't recall if every 5 or 6...) the system voltage will read 13.3V and on the next Key On, Engine Running it will revert back to 14.1 - 14.5V

I've noted this when I've had multiple stops or for example doing a rallye /drive with the car club.

when its in 13.3V mode, you can turn on anything (I've done heated seats, rear defog, headlights and fog lights all at once) and it will hold @ 13.3V, so its maintaining the battery, not discharging it.

So I'm lead to think that it does a charging cycle variation every so many Ignition On events by design. I've had my car over 3 1/2 years (original battery) and it has done this since new.

I had posted in another thread some years back about this observation when I first took delivery of the '16
 

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I made it a point to leave my car on the Battery Voltage gauge while I drove it the other day. It never varied from 14.1-14.3. I did have my stereo at max most of that time :D

A Guy
 

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The Bacon Hauler (‘12 Cop Charger)
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on my '16 - every certain # of Key On, Engine Running cycles (can't recall if every 5 or 6...) the system voltage will read 13.3V and on the next Key On, Engine Running it will revert back to 14.1 - 14.5V

I've noted this when I've had multiple stops or for example doing a rallye /drive with the car club.

when its in 13.3V mode, you can turn on anything (I've done heated seats, rear defog, headlights and fog lights all at once) and it will hold @ 13.3V, so its maintaining the battery, not discharging it.

So I'm lead to think that it does a charging cycle variation every so many Ignition On events by design. I've had my car over 3 1/2 years (original battery) and it has done this since new.

I had posted in another thread some years back about this observation when I first took delivery of the '16
Interesting...possibly some sort of de-sulfation process, or maybe even meant to prevent sulfation from occurring in the first place?

Does anyone know the location in the circuit where that voltage reading is collected? Does that represent the voltage at the beginning of the circuit or the end? If it was from the end, we could surmise the extra current was being consumed by task or piece of hardware that doesn’t run but once so often. But if it’s the voltage before anything in the circuit has done its work, we can’t really know if the extra voltage is meant for the battery’s charge or to do work somewhere along the circuit. Right?

IDK, that may not make any sense to someone who knows the difference between resistance and impedance. It’s likely sprinkled with a little gibberish either way, as I’m still trying to educate myself on the finer points of electron mass transit, but that’s the best my electrically challenged mind can express itself at this point.

Nuke, ZAPP, errr I mean OUT!

P. S. I do know that there is a difference between impedance and resistance (one applies to AC only and other is DC only, right??), but I will still use them interchangeably most of the time when engaging in high level convos with other electronically superior members lurking among us.

I’m sure it irks them to no end, but as a testament to their patience with me while I learn, no one calls me out on it...yet. (Pretty sure @ChallyTatum is fed up with how fast-and-loose I am with my electrical terminology though, so if I suddenly go MIA from the forum, check HIS trunk for my decomposing body!)
 

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Correct, Resistance is DC , Impedance is AC

A Guy
 

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The Bacon Hauler (‘12 Cop Charger)
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Correct, Resistance is DC , Impedance is AC

A Guy
Alright, now to figure out a way to keep them straight...

Let’s see...
<thinking>
<thinking>
I got it!

(Washington) DC (invites) Resistance (from opposing party)
(No) AC (is an) Impedance (for working in garage)

Resistance - DC
Impedance - AC
DC - Resistance
AC - Impedance

Easy peezy, hooker sleezy !!
 

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OK! Now

OHMs Law

Imagine a great, grass covered plain in the early days of our nation...

There's an Eagle (EMF or voltage), an Indian (I or current), and a Rabbit (R for resistance).

The Indian sees the Eagle flying over the Rabbit: I = E/R
The Rabbit sees the Eagle flying over the Indian: R = E/R
The Eagle sees the Rabbit and the Indian at the same time: E = IR

The resistance chart

Bad Boys Rape Our Young Girls But Violet Goes Willingly (Get Some Now )
Black, Brown Red Orange Yellow Green Blue Violet Gray White (Get Some Now Tolerance bands Gold, Silver or None)


A Guy
 

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The Bacon Hauler (‘12 Cop Charger)
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OK! Now

OHMs Law

Imagine a great, grass covered plain in the early days of our nation...

There's an Eagle (EMF or voltage), an Indian (I or current), and a Rabbit (R for resistance).

The Indian sees the Eagle flying over the Rabbit: I = E/R
The Rabbit sees the Eagle flying over the Indian: R = E/R
The Eagle sees the Rabbit and the Indian at the same time: E = IR

The resistance chart

Bad Boys Rape Our Young Girls But Violet Goes Willingly (Get Some Now )
Black, Brown Red Orange Yellow Green Blue Violet Gray White (Get Some Now Tolerance bands Gold, Silver or None)


A Guy
I can probably commit all that to memory, but the problem is my brain is currently full.

So if I memorize that chunk of info, it’s going to push some other chunk out. Leaving me in situation where I might be able to wire up a light fixture without fear of setting fire to house, but I’ll have lost the ability to do something else as a result.

What if I lose something really important, like how to wrestle a seized wheel hub off a spindle without the use of a slide-hammer?? (scissor jack BTW)

Or gosh forbid, even something more important, like how to tune out Mrs. Nuke’s incessant nagging while appearing to be paying attention and thus avoiding any further scream-talks (my word for conversations with her)???

I don’t know man, it’s a risky preposition, I’d better think it over before trying to learn this Omla law or Oom Bop or whatever it is....
 

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bit.ly/1lOUflp

A Guy
 

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(Pretty sure @ChallyTatum is fed up with how fast-and-loose I am with my electrical terminology though, so if I suddenly go MIA from the forum, check HIS trunk for my decomposing body!)
I think you give me too much credit, I have a hard time disciplining my dog...so having decomposing body in my trunk is a bit of a stretch. :p
 

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The Bacon Hauler (‘12 Cop Charger)
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I think you give me too much credit, I have a hard time disciplining my dog...so having decomposing body in my trunk is a bit of a stretch. :p
I used to have a neighbor that had a dog...danged thing was always telling me to do things I didn't want to do...like kidnap prostitutes and make them redemptive for their transgressions...or shoot all the squirrels in the neighborhood...weird dog man, weird dog...

I never followed any of this orders of course...I mean, his plans were so poorly thought out, none of them would have worked I bet...I'd have been in jail faster than you could have said Son of Sam!
 
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