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318 battery chargin light on all the time

1K views 13 replies 6 participants last post by  grant_baker 
#1 ·
I have read several of the posts relating to the battery light being on. I just purchased a 1991 318 and the battery light is on all of the time. It does not seem to have any starting/charging problems. I also had the clicking starter, but I installed the relay kit and this seems to have fixed that problem. I also replaced the ignition switch as someone told me this was the problem. This is what I have measured so far. Voltage at the battery is 12.3V with and without the engine running. Voltage at the center contact on the voltage regulator is reading 17.7V with the lead disconnected at full idle. Is the voltage regulator bad? Thanks.
 
Discussion starter · #3 ·
Dave- Thanks for the response. This is what I checked today. My engine is a P218G spec C.

Stator output = 54.2 VAC
Neither stator lead was open to ground
Stator resistance = .10 ohms

I checked the voltage at the battery without the engine running and at the voltage regulator output. Both were 12.45V. I then check both places with the engine running at full throttle and this was 12.30V. I then removed the lead from the regulator output and at full throttle it measured 18.75V. I did not have access to another multimeter, so I did it with the one that I have. Everything seems to check out, except for the high voltage output. I have not had the battery load tested, but the previous owner said he did. I just replaced the ignition switch and 20A fuse. Thanks for your help. -Andy
 
Discussion starter · #4 ·
Dave-

I was able to borrow an old analog multi-meter yesterday. I measured the stator output with it, it was right around 55 VAC. I did not know how to measure continuity or resistance. I then measured battery voltage at the terminals and at the voltage regulator output. It was consistent with the other meter, about 12.5V. I then measured the voltage at the voltage regulator with the lead disconnected. It only showed about 8V. I think the voltage regulator is the culprit, what are your thoughts? Thanks.
 
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