heavy battery drain

[beau]

hi guys, my lovely 3200 has decided to come up with a nice little issue...

within 4 hours the battery is drained enough to cause the car not to start, over night its so flat it wont even turn over.

battery- good
alternator- charging fine

its always drained the battery since i got the car, 3 days and it was flat, wasnt an issue, i could deal with this, but 3-4 hours is a bit of an issue... im only really mechanically minded, never touched electrics, where should i start? when i lock it without the alarm, it still goes flat.

 

[2b1ask1]

does it still have a tracker system in there even deactivated? My money would be on that killing the battery as they have their own small battery but when it goes it just draws from the main battery in an attempt to keep it charged... Could be installed in many locations though!

 

[CatmanV2]

You can phone them and ask. Early 4200s were not fitted in the factory.

C

 

[Chrisbassett]

Boot / glovebox lights staying on?
When you say the battery is good, have you had its condition checked, it may just have a weak cell or other issue that causing it to not hold much charge.

I'm sure you can also use a meter to check if there is a drain on the battery when the ignition is off, but I wouldn't know what a normal value would be or what a worrying figure would be...but I'm sure someone here will!

 

[MUC3200GT]

The alarm siren has some NiCD or NimH batteries which could shortcut when getting old, Just plug out the Sirencable (left side-box in the boot).



To drain a 72ah battery in 4h so that it doesnt start one would need 10..15 amps . With a meter one should see the current going down to few mA after car went to sleep mode. A boot light should have around 0.5 A.
After plugging on battery sometimes the parking light is swithed on per default, thsi has some (3..5) A this drains also over night.

 

[Contigo]

Connect multimeter to battery terminal so that you can see it with the boot closed and doors locked. Lock car and see if there is a significant drop in the voltage over say a ten minute period. Open the car and start removing a fuse at a time until you determine the root cause of the battery drain. There really is no easier method than this. Had same issue on my X5 and it was the LCU in the drivers footwell which had got wet due to water ingress and was causing a short circuit which in turn drained the battery.

 

[Gixerboy]

A more concusive test is to measure current draw(amps) when ignition off & key removed & all lights etc off.
Simply connect Multimeter set to Amps in SERIES between the removed negative cable & the Battery terminal.
Whilst undertaking test, remove boot lamp.
The meter with register current flowing through pernenant circuits e.g alarm / clock etc.
Your should only be reading mA anything greater than 1.5 amps suggests a current drain.

Basic ohms law Volts x Amps = Watts
So e.g a 10 watt lamp would register 0.83 amps.

I would check the heated rear window relay first, as these can overheat & melt the contacts together.this would cause a constant draw.

Warning do not switch on any high current items during the test! most multi Meters only have a 10amp internal fuse!

Hope this suggestion helps

 

[beau]

thanks guys, i will check this out some time, having to use a battery pack every morning atm!, iv not had a chance to look at it yet

 

[beau]

despite the battery tested to be ok (on a proper digital battery tester) i replaced the battery anyway, and guess what... so far its been fine!

 

[hodroyd]

Our cars need a good solid battery, so many things rely on it and fail quickly if they don't get it..!!