I think some of these guys just make this stuff up and say it. Regardless of whether it has any basis in truth.
To understand the likely problem you have to understand the basics of how batteries work. Nicad and nimh batteries have a normal state of zero charge. What that means is that they are naturally uncharged and suffer no ill consequences from being discharged. In fact they discharge rapidly on their own over time(relative to naturally charged type batteries). Running them to zero charge or letting them sit is fine and they can easily be recharged afterward.
Now what you have in a car is a lead acid based battery. Its natural state is charged. Running a lead acid battery down and leaving it that way for months will destroy the battery cells and they ability for them to hold a charge. It doesnt matter how much you charge it after that. It will not hold the charge for any significant period of time. The thing to remember is that a battery can still work with a very damaged cell. As long as there arent too many of them. But based on everything you said your battery is the likely culprit. Don't ever run a car battery down and leave it that way.
The previous poster was correct. Put a meter on the battery with the car running. If it registers about 14-15 volts it isnt an alternator problem or a regulator. Also correct is that with the car not running it should be lower 12.5-13.2 volts in general as each cell usually generates 2.2 volts and there are 6 of them- 6X2.2=13.2. (when a battery is manufactured).
If youre getting a good charge off the alternator then the problem is the battery isnt ACCEPTING the charge and that means damaged or dead cells.The light is coming on because the problem is on the edge of the sensing system as the battery is taking some charge, so youre getting a ghost light. Keep running the battery and youll get a solid light eventually as the battery gets worse. Replace the battery after you put the meter on to check the charging system. And dont believe everything you read.
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Originally Posted by 94BMW325i  any flickering if you were to turn on your radio, headlights and other accessories? |
