Thread: Battery Monitor

My P38A couldn't be locked/unlocked with the keyfob when parked at St Marys railway station when I worked in the signal box there. I didn't use the public parking spot but in the staff parking next to a hut that had radio transceivers in there.

Hi Laurie and my apologies, I have just had a Triple Bypass and a Pacemaker inserted in my chest and they are filling me up with drugs, morning, noon and night, so my head is still off with the fairies.


If my head had been with it, going on your BM2 graph, it actually confirms your BM2 is NOT activating the Bluetooth in your D5 and your Bluetooth is NOT turning on at all.

If the D5 Bluetooth was being continually activated, the graph would be of a saw tooth shape. Where the voltage would drop as the D5’s Bluetooth activated and then the voltage would rise slightly again when the D5’s Bluetooth turned off.

You have something that is applying a HUGE current draw from the instant you turn your ignition off.


In one of our phone conversations, you stated you could hear a buzzing or clicking sound.

What you need to do is start pulling fuses. One at a time, until you stop the buzzing, which should then help you find the problem.

That is exactly what I thought too Tim.

They have done a software update also. Perhaps that might fix the issues. I will have to look at it pretty closely when I pick the car up in a week or so. Might have to set up my multi-meter and check voltage hourly and record what is happening. Surely they wont be able to say that is waking the car up like they have with the BM2. Also bought myself a clamp meter so I can see what kind of draws are occurring in an attempt to find out what is normal.

I also thought that if the car was being woken every 45 minutes by the BM2 and that was the cause of the battery drain then it would not be a consistent curve being shown but a jagged line as the power goes on/off. The BM2 is indicating a consistent draw.

Put a few more graphs up also.

Look after yourself Tim.

Hi Laurie, your last graph is the most interesting.

It clearly shows you have lost at least 50% of your battery's capacity in just 12 hours.

Forget all the pulses, the main loss occurs without any interruptions and that sort of battery capacity loss is being caused by at least a 5 amp continuous load applied to the battery.

That is not the D5 waking up. It is a continuous load being applied.

Check for mV across fuses. Any reading shows a parasitic draw.

I pick the car up tomorrow. They have done a software update and reset it for a new battery. They tell me that there is no battery drain but have removed my battery monitor. They also tell me that the battery monitor was pulling 35mA about 20x what it should but will test it myself when I get it home. That was obviously not the issue.

Tim, I had a similar number in mind for the draw so should be easy to test for. I assume they removed the battery monitor so it is totally standard for their testing.

Now trying to find out if there is a threshold draw where the car is woken up.

For my own peace of mind I am going to test the draw from stopping the car & locking till it goes to sleep to see what it is pulling and for how long. Lock myself in the boot and watch the meter.

Well I got the car today and they said it was fixed. No sound coming from it they told me. Too noisy to check. They told me they had the car parked in their shed over xmas and new year and no low battery warning. They reported no battery drain.

Got it home (110 Km) and parked it (double locked) about 1pm. Out to the car at 7.30pm open the door and low battery warning. 11.9 volts. I knew that was going to happen as I could hear the electrical whirring sound when I went out. Lot quieter environment. Guess what I said.

Locked myself in the back of the car and put the amp clamp on and took readings. Double locked the car and the clamp showed 4.3 amps. 15 minutes later still basically the same. That is a good drain. Jumped to 7.5 when I unlocked the car.

Dealer sent email. Wonder if they will call tomorrow?

Might not be of help but....

I've recently.had a fix on a not loandrover with a similar issue,

Turned out to be a bad connection one of the environmental.control flaps, similar symptoms and the humming noise was the flap stepper trying to wind the external air flap closed but the becm wasn't getting the position signals.back so it just kept cycling the stepper from limit to limit.

Turning the ac off before shutting down the engine seemed to fix it temporarily and a simple disconnect reconnect the harness for the vent motor/position sensors.fixed it.

Hope it's something similar and nothing exotic.