Hey guys and gals, I have looked everywhere, and can not find this issue. I just replaced my alternator, the old one had bad bearings, and to top it all off someone had stripped the threads on the top mount AND bent the bolt (got a new bolt from Honda the day before I did the install of the new alternator). The new alternator seems to work great, however, at 6,000+ RPM, I noticed that the battery light comes on. I have no idea if maybe I have too much or too little tension on the belt, or maybe if I have a grounding issue that the old alternator didn't bring out, or if I just got an alternator that is toast (it is a brand new alternator, not a reman.). Any insight would be welcome, and if I am just blind and did not see a thread about this issue, I want to apologize now.

 

Start simple. Belt slipping?

 

That is one of the things I am going to be checking, going to go by a friend's house as soon as he is off work so we can both look things over.

 

I had this problem one time and discovered that I forgotten to tighten the upper mount bracket bolt.

 

Well, I will double check the tension and make sure the upper mount bolt is good and tight. I do need to replace my belts as well, so for all my luck, it is just the belt itself causing the issue. Thank you for the quick response.

 

Well, I checked the tension in the belt, everything is fine and it still has the charge light come on at high RPM, I am stumped.

 

Well, I can try that this evening.

 

I had this problem in my 97 civic hatch. There is probably a faulty diode in the bridge or a bad voltage regulator. This is often overlooked when alternators are remanufactured. Generally it's the coils, or the bearings that fail first.

I doubt its a slipping belt unless it happens when you punch the throttle. An easy way to check whether or not it's the bridge is to rev the engine in neutral and maintain rpm at 1k, 2k, 3k, etc until the light comes on. Let say it comes on at 5k but goes off when you lower it to 4k or so then it's very likely the diode bridge or rectifier.

The voltage regulator limits the amount of voltage being sent to the battery/car since the voltage varies with the rpm of the car.

The diode bridge ensures the current only flows one way since the alternator generators AC and the battery is DC. If one of the diodes in the bridge becomes faulty (usually 6-8 diodes in the bridge) it may cause the power output to be reduced which could cause the battery light to come on in a certain rpm range.

 

6000 rpm.. are you fing kidding me..

 

What? you don't drive your car hard once in awhile? Yes, I open my car up from time to time to get on the highway, and can enjoy it more while using less fuel than my Grand Prix used..... Is there an issue with me pushing my car to it's 6,500 RPM red line?

 

Oh, wait, you drive a VX, if I remember correctly it doesn't turn more than 5,800 RPM. If you really don't like RPMs, then you should not look at my roommate's 1999 Civic Si.....8,250 RPM fuel cut off stock....

 

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