Strange battery Drain when engine is off

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es300tdi

New Member
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10
Location
Dorset
Hi all!

I have a strange issue with my Disco 300tdi ES.

About two weeks ago the battery appeared completely dead and the motor would not start, there was around 6 volts in the battery.

I purchased a brand new battery and the engine started fine, I checked with a volt meter while the enginer was running and I could see the alternator was charging at approx 13.8 volts.

However, 5 hours later I went to start my motor again and there was only 8.5 volts in the new battery?!?

Any ideas? :confused:

At the moment after everytime I have driven the disco I have to pop the bonnet and disconnect the earth, it appears something is draining the battery at a considerable rate when the engine is turned off. Ive done the usual and check all lights, radio, etc and I'm not having much luck.

I did recently do alot of welding on the chassis (battery was disconnected during this) and a friend suggested I may have melted a wire? however, would this drain the battery when the car is off?

I need help please.

Kind regards,

Andy
 
Hi Daz,

Just a thought, I have purchased this item from Ebay...should be here on Tuesday so I shall let you know.

Will this device be suitable to check both the fuses in the main fuse both underneath the steering unit and the larger fuses in the fuse box under the bonnet?

Kind regards,

Andy.
 
With that amount of currant draining from the battery you could look at the alternator prehaps the diode pack is iffy it's not unknown, to find out fully charge your battery and disconnect the wiring to the alternator overnight if u still have the low battery voltage next day then it's not the diodes, so carry on with plan A.
 
Hi all!

I have a strange issue with my Disco 300tdi ES.

About two weeks ago the battery appeared completely dead and the motor would not start, there was around 6 volts in the battery.

I purchased a brand new battery and the engine started fine, I checked with a volt meter while the enginer was running and I could see the alternator was charging at approx 13.8 volts.

However, 5 hours later I went to start my motor again and there was only 8.5 volts in the new battery?!?

Any ideas? :confused:

At the moment after everytime I have driven the disco I have to pop the bonnet and disconnect the earth, it appears something is draining the battery at a considerable rate when the engine is turned off. Ive done the usual and check all lights, radio, etc and I'm not having much luck.

I did recently do alot of welding on the chassis (battery was disconnected during this) and a friend suggested I may have melted a wire? however, would this drain the battery when the car is off?

I need help please.

Kind regards,

Andy
glow plug timer relay, big black one on the outside of the fuse box, just unplug it.
 
Discool, I'll take a look into the Alternator suggestion...I only replaced it about 5 weeks ago...3 weeks later and this problem has started.

Regards,

Andy
 
glow plug timer relay, big black one on the outside of the fuse box, just unplug it.

Fieldman, Can you explain a little more? Big black what sorry on the outside of the fuse box? do you mean fuse in the car or under the bonnet...Thank you. Have to bear with me Im not fantastic with mechanics.

If I unplug it, what am I looing for? Do I need to replace? is it needed at all?

Thanks again.

Andy
 
If I unplug the glow plug timer relay, is i something that must be replaced? I don't quite follow....Can I get on without it?

Regards,

Andy
 
Fieldman, Can you explain a little more? Big black what sorry on the outside of the fuse box? do you mean fuse in the car or under the bonnet...Thank you. Have to bear with me Im not fantastic with mechanics.

If I unplug it, what am I looing for? Do I need to replace? is it needed at all?

Thanks again.

Andy

Open the bonnet, on the left hand side as you face the vehicle just a bit further back than your ballery you will see a fuse box. At the far and of that fuse box you will see a large Black Relay. see attached photo. unplug that, charge yer battery, check it tomorrow and I bet it's full........
 

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Fieldman, Can you explain a little more? Big black what sorry on the outside of the fuse box? do you mean fuse in the car or under the bonnet...Thank you. Have to bear with me Im not fantastic with mechanics.

If I unplug it, what am I looing for? Do I need to replace? is it needed at all?

Thanks again.

Andy
sorry, had the same problem battery drain would go for weeks and be ok then one day away from home i had to have the rac jump start it, was told it needed a new battery, new battery fitted and it started, 4 hours later whent to start it flat battery again. turned out it was the glow plug relay on my 300 it was screwed on the out side of the under bonnet fuse box i just unpluged it, ran around with out it for 2 month.
 
Fieldman unfortunately it's not the glow plug timer relay...I guess that would have been too easy! :(

Battery was fully charged on Saturday evening when I disconnected the large black plug. Went out half an hour ago and the battery is dead as a dodo :confused:

A friend suggested atleast pulling out fuses and putting them back in, aparently a small spark when the fuse goes back in could mean there is a current being drawn.....I have bought this amp current tested from Ebay which I should have on Tuesday....fingers crossed this tells me a little more.

Thanks for the help so far guys....If anyone has any other suggestions please get in touch,



Andy.
 
I had this just last week with my 300, alternator died, replaced it with a brand new item only for it to be faulty and drain my battery overnight. Replaced the alternator again and my problem has been solved.
 
Hi chaps,

Think we might be onto a winner!

I have left the vehicle for 4 hours, battery was 13.8 volts and now is 6.5 volts.

Engine is stone cold and Alternator is very warm.

Alternator was recently replaced and there for still in waranty :clap2:

I shall keep you posted!

Cheers
 
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