440 Flat battery

  • Thread starter Thread starter Mark121739
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Mark121739

Hi all
I have a 94 440 and every morning
i have a flat battery but i have no idea
what is draining the battery,
any suggestions would be helpful.

(ps its a new battery)
thanks Mark
 
Mark,

Have you or anyone else worked on ANY of the electrics prior to this
happening?
Was this problem the reason you got a new battery?
Has a new radio or alarm just been installed?
Post ignition electrical drains are easy to track down by attaching an
ammeter with the ignition off, and selectively disconnecting stuff (by
removing fuses), until the ammeter reading drops, it's also possible for
faulty rectifiers in the alternator, or faulty central locking controls to
cause this problem, automatic electric aerials, and small lamps such as
boot/bonnet lamps can cause this as well, as can a faulty battery.
Some bad news; if your new battery has discharged so many times, then you
need another, because the plates will have sulphated up already, reducing
it's capacity, find the problem, then replace the battery.

Good luck, Ken 740 gl, moded to gle owner
 
I have a 94 440 and every morning
i have a flat battery but i have no idea
what is draining the battery,
any suggestions would be helpful.
(ps its a new battery)
Click to expand...

Easy: put a current meter in series with the fuses and see if a
current runs when the car is switched off. Measure all. Once you found
the one, disconnect all devices until the currewnt stops.

It id also possible that your battery is not charged correctly.
Measure the battery voltage when the motor is on, it should be about
13.8 to 14 Volts.

Regards,

Pieter Hoeben
 
Don't know where you are or where you got it from - but I'd be tempted to
take it back:-))
Seriously tho - it could be something simple like you internal courtesy
light is on when the doors are shut, or more complex like the others are
suggesting. Check that all lights are off inc glove box, boot etc.
Threaten it with the scrap yard - that works with my 440.
 
Mark121739 said:
Hi all
I have a 94 440 and every morning
i have a flat battery but i have no idea
what is draining the battery,
any suggestions would be helpful.
Click to expand...

One of two things:

Either you have a light stuck on- i.e. glove box, ashtray, or boot light. OR
you have a failed diode in the alternator which is causing the discharge.

A tip with the alternator is with the engine stone cold, place your hand on
it- if it feels above ambient temp then its definately at fault.

Tim..
 
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