Visionzwp21

I plugged up my BEL RX65 radar detector and have it set to show voltage. I noticed that when I first start up the car, the voltage sometimes is at 14.4V, but at some point, the voltage drops down to 13.3-13.5V. It stays at that voltage for long periods of time and I dont ever see it go above 14 again until sometimes a cold start.

The car is 3 years old so I was thinking it could be the factory battery. Since I just got the car im not sure if the battery has been replaced. What model was the factory battery? I went ahead and purchased an Optima Yellowtop because I use those in all of my cars.

I have been looking through the manual and I was wondering if it could be the Variable Voltage Control System? Can anybody shed some light on this?

Ghozt

Hmm good question. I noticed my battery operates at 13.4 volts when off, and 14.3 when on. Never checked it after driving for a while with it still on though. Usually low voltage can indicate low charge; my last battery that had problems holding a charge used to give my Viper low battery voltage alerts if it sat for over a day without being started. Replaced with a new battery that can hold a charge, and no more issue on that front.

Visionzwp21

I installed the Optima YellowTop about 4 days ago and still noticed the same problem. Im guessing it could be the alternator, but it charges the system well based on the fact I can always start the car (no battery drain). I was thinking about doing the Big 3/Grounding Kit upgrade. When the car is off, I have a voltage reading of about 12.7 V

Ghozt

The battery I had a problem with was my last Optima Yellowtop. Dunno if it was a dud or what, but it sucked at holding a charge. I also have a grounding kit. Curious though why the voltage would drop while driving, yet start at the 14.3 as is expected.

1996blackmax

iTrader: (2)

Mine does the same thing. Starts out at over 14 then goes down to to around 13.4. When off, it goes around 12.7. I have no issues with starting the car, even after several days. I also have no dimming lights, such as my dash lights when I have my system on the louder side.

Visionzwp21

At least im not alone. I started to notice that when the car is around 13.5 or below, the passenger window and rear windows will start to stutter. Do you have that issue? Trying pushing them all down (or up) at once

1996blackmax

iTrader: (2)

I haven't noticed that, or any other issues associated with it. I thought about doing the big three, but didn't feel it was necessary.

Visionzwp21

I found this explanation of what the Variable Voltage Control System searching Google. I didn't see the explanation on here so I wanted to share it with everyone

"Looking through the FSM for the current value of the alternator, I discovered a detailed explanation of the power generation variable voltage control system. By varying the voltage to the generator, engine load due to power generation of the generator is reduced and fuel consumption is decreased.
"The battery current sensor is installed on the battery cable at the negative terminal. The battery current sensor detects the charging/discharging current of the battery and sends a voltage signal to the ECM according to the current value detected." This tells me that any aftermarket load connected directly to the negative battery terminal (vice body ground) will not be accurately detected and the system will not fully compensate for that devices current draw. A hyperground system may also cause load detection errors because the current sensor has been bypassed.
"When there is no PWM command signal, the generator performs the normal power generation according to the characteristic of the IC regulator." If we disconnect this system, it appears to provide maximum electrical power (based on RPM) full time."





http://www.clubfrontier.org/forums/f...-system-79813/

Visionzwp21

Another interesting article

http://www.redarc.com.au/images/uplo...-sept_2012.pdf