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Discussion Starter · #1 ·
I was wondering if anyone else monitors their voltage while daily driving. I have a voltmeter built into my Passport 8500 X50 so I just leave it to display volts. Sometimes when I'm driving around, no real reason, I just drop to 12.2 volts for a few minutes, with no music or anything on.

This doesn't change if I'm in neutral or in gear, or what my RPM's are at. It seems to happen all by itself, as there is no pattern when the voltage drops to 12.xx so I was just wondering if it's the ECU just cutting the alt. off to conserve energy or something and I'm just running on battery.

Does this happen to anyone else? My battery is fine and my alt. seems to be functioning fine. I got my alt. tested at Autozone and he said it is fine, diodes and Voltage Reg. are fine...

If I use a DMM on my alt while my car sits still, I've never actually seen it drop to 12.xx volts with nothing on, so it's possible just the radar detector is getting voltage drop somehow but I'm not really sure how...

Any ideas?
 

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I noticed the same thing after installing my headunit and observing the voltage on that. I went to the dealer a couple times and they just told me there was no problem, but wouldn't explain why the voltage would drop. After I got my HO alt, the voltage would still randomly drop for no apparent reason. I asked Dominick Iraggi about it and he told me that many Hondas do this and it is meant to give the car more power while driving under loads.

Seems stupid to me since a 200amp alt at 14.4v will pull less than 5hp. Dropping the voltage to 12v doesn't seem like a significant enough gain to bother with, but whatever, not much can be done about it.
 

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Phlipcyde said:
I noticed the same thing after installing my headunit and observing the voltage on that. I went to the dealer a couple times and they just told me there was no problem, but wouldn't explain why the voltage would drop. After I got my HO alt, the voltage would still randomly drop for no apparent reason. I asked Dominick Iraggi about it and he told me that many Hondas do this and it is meant to give the car more power while driving under loads.

Seems stupid to me since a 200amp alt at 14.4v will pull less than 5hp. Dropping the voltage to 12v doesn't seem like a significant enough gain to bother with, but whatever, not much can be done about it.
Ohhh that explains a lot, I get random voltage drops as well shown on my Pioneer Premier Headunit
 

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Discussion Starter · #6 ·
quality_sound said:
You guys sure it's not the A/C compressor cycling? And before you ask, yes it'll cycle even with the A/C off.
Possibly, is there any way to know while driving if that's what it is? I noticed that if it drops, and I turn the AC on and off real quick it'll kick it back up to 14.xx.
 

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See this post on how to disable the AC when YOU want to, and force the light to light up when it's been turned on via the 'defrost' button or by the normal means.

this will indicate when the AC unit is operational, not just when the compressor is running. fyi

whenever you put the fans to the windshield position, the AC will kick in and not tell you it's on.

http://www.8thcivic.com/forums/showthread.php?t=42325&referrerid=8713
 

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Discussion Starter · #10 ·
Just for anyone looking at this thread in the future:

This is the ELD (Electronic Load Detector) at work, which is a part of our ECU. According to my thorough research, currently the only way to disable this feature is using Hondata FlashPro which is quite expensive.

Please advise if anyone has figured out another or different way to disable the ELD besides getting the ECU re-flashed.
 

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:think:

how would the ECU limit the altenators mechanical functioning ? its belt driven.

my guess is its the fans kicking on, civics dont have that fancy altenator that new 5series come with to be able to go on and off at will.

what I said can be completely wrong, and probably is. take it for face value, $0.00
 

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Discussion Starter · #14 ·
:think:

how would the ECU limit the altenators mechanical functioning ? its belt driven.

my guess is its the fans kicking on, civics dont have that fancy altenator that new 5series come with to be able to go on and off at will.

what I said can be completely wrong, and probably is. take it for face value, $0.00
Yes, what you said is, indeed, completely wrong. But thanks for the input, anyways.
 

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A lot of times it is the voltage regulator.

My last vehicle with an HO alt did the same thing as your alt generates the power but your regulator decides how much and when, well at least thats what I remember....

Copy+Pasta

When upgrading to a high output alternator you rarely need to change your voltage regulator. The voltage regulator controls the alternator output by sending power to the rotor (field). The rotor spins inside of the stator, the reaction between the rotor and stator is how power is induced within the stator. The voltage regulator senses the battery voltage, if the battery needs more power the voltage regulator sends power to the rotor coil turning the alternator on. If the regulator senses that the battery or system needs a lot of power it sends maximum voltage to the rotor making it a big electro magnet thus causing the alternator to produce maximum power. If the regulator senses a small need at the battery it will send minimal power to the rotor causing the alternator to produce little power.
 

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Discussion Starter · #16 ·
A lot of times it is the voltage regulator.

My last vehicle with an HO alt did the same thing as your alt generates the power but your regulator decides how much and when, well at least thats what I remember....

Copy+Pasta

When upgrading to a high output alternator you rarely need to change your voltage regulator. The voltage regulator controls the alternator output by sending power to the rotor (field). The rotor spins inside of the stator, the reaction between the rotor and stator is how power is induced within the stator. The voltage regulator senses the battery voltage, if the battery needs more power the voltage regulator sends power to the rotor coil turning the alternator on. If the regulator senses that the battery or system needs a lot of power it sends maximum voltage to the rotor making it a big electro magnet thus causing the alternator to produce maximum power. If the regulator senses a small need at the battery it will send minimal power to the rotor causing the alternator to produce little power.
No, this is not a product of the voltage regulator, but rather the Electronic Load Detector.

The voltage regulator could certainly cause problems such as this, but not in this case.
 
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