In article ,
David Hansen wrote:
I would suspect a fault in the car wiring and track this down. More
and more things are being connected directly to the battery,
sometimes without even a fuse, so are able to gently drain the
battery. If one of these has gone wrong then it will be able to
drain the battery more rapidly than designed to do. It may take a
while to track down what it is, but things which are available even
when the ignition is not turned on are where I would start looking.

If it's discharging overnight and nothing is obviously on one possible
cause is a failed diode in the alternator rectifier pack. They can fail
short circuit resulting in a permanent discharge of about 6 amps. Feel if
the alternator back is warm when the engine is cold, if you can't measure
the quiescent current.

--
*Lottery: A tax on people who are bad at math.

Dave Plowman London SW
To e-mail, change noise into sound.