Help - Electricity Drain

[bertiejaffa]

Hi all,

As you will know I have recently bought a Z4MC which I am thoroughly enjoying, however I have noticed that there is a large power drain somewhere when the car is parked up. I have checked for the usual things that I can think of such as ensuring the courtesy lights are off when the boot is closed and making sure that there are no auxillaries plugged into the cig lighter etc.

Any ideas what this could be? Has anyone experienced similar?

I did wonder if there is a way to disable to alarm/immobiliser using a particular set of key presses when locking the car?

Open to any suggestions as it is currently losing around 1v per day!!

I have checked the battery and it is fine and I have put my spare one on and that has the same issue - the alternator seems good - charging at 14v when the engine is running.

 

[colb]

Testing Parasitic Draw via Fuse Voltage Drop

Using This Method Prevents the Vehicle From Waking During Testing

us.autologic.com

 

[NZ00Z3]

The Z4 is based on the E46. The E46 has a habit of the blower fan Final Stage Resistor (FSR) failing where it becomes a parasitic load.

RealOEM.com shows that the Z4 does not use the same FSR as the E46, but it looks to be very similar in design.

The usual test is to unplug it and see if the parasitic draw is still there.

 

[GazHyde]

Have you checked the light in the rear storage bin between the seats? The switch that turns it off commonly fails, and I had a small drain until I removed the bulb.

 

[bertiejaffa]

The Z4 is based on the E46. The E46 has a habit of the blower fan Final Stage Resistor (FSR) failing where it becomes a parasitic load.

RealOEM.com shows that the Z4 does not use the same FSR as the E46, but it looks to be very similar in design.

The usual test is to unplug it and see if the parasitic draw is still there.

can you advise where it is please as I’ve no idea so I can unplug it. The fan does work fine though?

 

[bertiejaffa]

Have you checked the light in the rear storage bin between the seats? The switch that turns it off commonly fails, and I had a small drain until I removed the bulb.

I’ll have a check, didn’t think of that one

 

[Pingu]

I recommend a clamp ammeter with bluetooth. Mine cost about £40.

Something like this...

Digital Clamp Meter AC DC Bluetooth APP Control Multimeter Tester Auto Range | eBay

Phone APP Connection Yes. AC/DC current, resistance, capacitance, temperature, frequency, diode Test. DC Current Range Accuracy Resolution. Resistance Range Accuracy Resolution. AC Current Range Accuracy Resolution.

www.ebay.co.uk

Connect to the app via bluetooth and clamp it around either of the battery cables - I usually use the earth.
Test for parasitic drain. I usually do it by removing fuses one at a time, but you have to eliminate any circuits that are live when the fusebox is accessed (such as the bonnet alarm switch on the Z3).

 

[bertiejaffa]

I recommend a clamp ammeter with bluetooth. Mine cost about £40.

Something like this...

Digital Clamp Meter AC DC Bluetooth APP Control Multimeter Tester Auto Range | eBay

Phone APP Connection Yes. AC/DC current, resistance, capacitance, temperature, frequency, diode Test. DC Current Range Accuracy Resolution. Resistance Range Accuracy Resolution. AC Current Range Accuracy Resolution.

www.ebay.co.uk

Connect to the app via bluetooth and clamp it around either of the battery cables - I usually use the earth.
Test for parasitic drain. I usually do it by removing fuses one at a time, but you have to eliminate any circuits that are live when the fusebox is accessed (such as the bonnet alarm switch on the Z3).

Thanks Gary - that takes me back to my electrician days !