2004 Citreon C4 Alternator L/DFM wire causing parasitic draw.

[Glen Synt]

I've been having a problem with my car's battery draining overnight, I narrowed it down to the L/DRM wire of my alternator, It draws 80 milliamps while the key is off, I unplugged it overnight and it didn't drain the battery.

Now I don't know why this would happen. Is it the alternator? or something else in the circuit?

 

[James]

The fault is likely to be the battery itself.
A healthy battery should still start the car with that load being drawn for weeks.

 

[Glen Synt]

The fault is likely to be the battery itself.
A healthy battery should still start the car with that load being drawn for weeks.

It's a brand new battery, it was the first thing I replaced when I started having the problem, I'm using a fairly cheap clamp meter to measure the draw I don't know how accurate the 80 milliamps is.
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It's a brand new battery, it was the first thing I replaced when I started having the problem, I'm using a fairly cheap clamp meter to measure the draw I don't know how accurate the 80 milliamps is.
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sorry, my bad I mean 800 milliamps (0.8) amps

 

[James]

Have you ever charged the battery?

Also, I would not be using a clamp meter for measuring currents that small unless it was specifically designed for measuring mA of DC .

 

[Glen Synt]

yes I have charged the battery completely, it drains in about 18 hours or so

 

[James]

Ahh, 800mA is enough to discharge a battery completely within a couple of days.
If it is not being fully charged by the previous days driving then it could easily have discharged enough to be unable to start the car next day.

I would be taking it to a garage who can replace or repair the alternator

 

[Glen Synt]

I would be taking it to a garage who can replace or repair the alternator

yea I'm trying to avoid that if possible as its $350 AUD for a replacement alternator and I'm not completely convinced its the alternator itself

 

[James]

As soon as it is installed you can measure the current drawn at Rest and you will know if it is going to fix the problem.