High rev electrical issue

[BDSCRPN]

Okay I've searched and searched this one out but no answers yet.

Car:
2000 v6 3.8L
5 speed
optima red top battery
GT MAF with GT cold air tube
Factory stereo with after market add on rca amplified with 600w jensen 4 channel bridged to 2 with 2 12" subs 1.5 micro farad cap (this may not be important but just in case)
Also I've owned the car since was still under factory warranty, one prior owner no mods done till I got it. Even then nothing major.

Problem:
Under load and in the higher rev range 4k plus, battery light shows. Then radio and instrument cluster blank out. Meaning completely dead for about 2-3 seconds. Then at some point the cluster comes to life all dials read make then drop dead and come back to life where they should be. battery light remains for about 10-15 seconds and engine is still running during this entire time. never misses or loses power at all. First time this happened it would only happen even with car stopped in parking lot at 4k +. Granted with car stopped and out of gear maxes at 4k then limiter kicks in anyway. but even in neutral rev to 4k and bat light comes on stays on for about 2-3 seconds then goes off. Newest electrical item in the car is the cap. I did install correctly been working with electronics and electrical all my life. Did pull the amp fuse under hood and didn't seem to have same issue at 4k. However has been disconnected for a while now and problem keeps rearing its head every so often. Amp and cap have remained disconnected so not the problem. Thought maybe cap was causing the issue cause never had any electrical issues before. Cap was installed for about 2 months never had any issues at all. I know lot of info but figured might help.

Anyway any suggestions or ideas would be appreciated. I'm to the point I don't care how wild as long as they are realistic.

 

[BDSCRPN]

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[BDSCRPN]

well think I've got it figured out. After reviewing multiple circuits seems it is my tach craping out. Which is fine since I planned on pulling factory gauges and putting in some that actually work
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[wmburns]

I would have thought this problem would be related to over loading the alternator. Or weak alternator B+ or ground.

The dash battery light simply comes on when ever the voltage drops above/below a pre-determined voltage level.

So unless you are trying to say the tach is messed up and your actually RPM's are MUCH higher, I fail to see how a tach signal can make a battery light come on.

 

[Aeroman]

The battery light (or charge light indicator) can come on if the field circuit wire (which is the wire the bulb is connected to) goes to 0v, which would mean you have a NO Charge condition. When there is 12v on both sides of the bulb it goes out since no current can flow through the bulb, which is the normal condition with KOER. Cause could be bad Voltage regulator, burnt field coils, failed rectifiers etc.

You can check if the battery is charging simply by measuring the voltage across the battery posts with the engine running . It should read between 14-15v if all is well. If not you do have a charging problem & need to have the alternator/ rectifiers checked or there is a chance the Voltage regulator has failed ($20 item).

Aeroman.

 

[38stang]

You need a alternator. the bulb comes on if the voltage from the alt. gose lower than 12 volts or higher than 15 volts. your battery voltage with the engine running shoud be between 13.6 to 14.8 if not then you need a alternator.

In your case the light is coming on at high RPM. that usually means the voltage reguator is bad in the alternator and it is leting the alternator over charge the system. meaning the voltage is going up in the 15-18 volt range at high rpm which will the kill electronics in the car.

 

[Aeroman]

Having thought about this again, it sounds like your carbon brushes are getting close to their lifes end. Install a new voltage regulator it comes with the brushes/ springs as part of the unit. I dont think you can buy just the brushes.