BMW 120d - dead as a dodo - flat battery?

[MitchT]

The OH's E87 (Feb 2005) 1 Series appears to be dead. Press the button on the fob to unlock the car and nothing happens, though there is a strange muffled ratting noise coming from somewhere deep within the car. Use the key to unlock it, open the door, and the window controls inside the driver's door appear dimly lit, but nothing else is illuminated. Put the key in and try to start the car and nothing happens at all. Is this the battery?

[SebringMan]

it does sound like it.

If you have access to a multimeter check it via that first. Another choice is to go to Halfords and to get them to test it. A £40 battery tester from Foxwell (BT-100) can save you the trip to Halfords however.

[RizzoTheRat]

If the reason is similar to my wife's cars recent flat battery, jump start it and then turn off the interior light.

If it's been flattened due to something left on you might get away with just charging it back up again, but it could be the battery is knackered and needs replacing. After spending several days flat my wife's one could just about start the car from a full charge but not if it had been left a couple of days.

[helix402]

If you try and jump start it use the terminals in the engine bay, not straight on the battery.

[MitchT]

Most likely a knackered battery. The car is 13 years old and the battery is the original one!

I don't know if leaving an interior light on would flatten the battery on a 120d as nothing seems to be "live" when the car is turned off. I once flattened the battery on my E36 by leaving an interior light on, but on my E36 I can charge my phone with the ignition off. On my OH's 120d my phone will only charge with the engine running so I guess nothing is powered with the ignition off.

I have a CTEK MXS 5.0 so I might try to give it a boost with that so it can at least be driven to get a new battery. Can that be attached to the terminals in the engine bay like jump leads can?

Finally, does anyone know if this car should have stop/start? In all the years the OH has had it there has been no evidence of this feature, yet when she phoned our local BMW indy for advice they were adamant that this car does have stop/start. The battery price seems to be £100 less for a non-stop/start model but we don't want to get the wrong one it it turns out the car does have this feature and it's somehow been disabled the whole time she's had it!

[Elliot2000]

Start stop didn’t come in till 2007 so you should be fine with a normal battery. Have you checked that the battery is at fault tho?

[MitchT]

Elliot2000 said:

Have you checked that the battery is at fault tho?

I'm trying to get some charge into it so it can be taken to the garage where the problem can be diagnosed. I wouldn't know where to start.

I've attached the CTEK via the terminals under the bonnet and there's now an interesting and fairly loud clicking noise coming from just under the windscreen. You can hear it through the glove box too - it's like it's under the bonnet but right behind the glove box. I don't know if that's simply a symptom of a flat battery or if it's something electric trying to do something when it shouldn't, which might be what drained the battery. The same noise was evident when I tried to unlock the car with the fob a couple of days ago.

[Elliot2000]

It could be the engine ecu relay clicking- that’s where it sits, does it start now it’s charged up?

[MitchT]

Elliot2000 said:

It could be the engine ecu relay clicking- that’s where it sits, does it start now it’s charged up?

I've only just started charging it so too early to say. Not even responding to the fob yet.

ECU relay clicking - is that going to be expensive?

[MitchT]

Had the CTEK on it overnight and it's still dead. The red light on the CTEK had come on which I believe indicates that the battery's not playing ball. Most likely going to get it recovered to the indy that the OH uses as there's nothing more I can do with it.