I thought I would let you know about an issue I had with the car draining the 12v Battery and Hybrid battery at the same time. I had a call from Land Rover after a theft alert on low battery. It had been stood on the drive for three days, not plugged in, as we have been driving in my wifes car.

The car was totally dead with no power. I called Land Rover Assist, 4 hour wait.

I accessed the car with the emergeny key, opened the bonnet and attempted a jump start off our 2007 Defender, left it connected for 10 minutes using the jump leads on to the dedicated posts in the engine bay. It would not wake up. My jump pack was locked in the boot, no power, no access to the boot.

Land Rover asssit turned up (not the AA fortunately) immediately got the P440E started with a jump pack (POWER START PS700 12V BOOSTER PACK - £300). Apparently its important to jump start with the correct voltage as a protective relay can isolate the 12v battery which can only be changed by Land Rover on a ramp, as its under the drivers seat.

Land Rover Assist diagnosed a faulty Battery Energy Control Module (BECM), this took 70% charge out of the main drive battery and discharged the 12v battery in three days. They did a software update on the BECM and the main drive battery appears to be holding its charge when not plugged in. Fingers crossed this issue does not arise again and it was a software glitch.

The Land Rover Asssit chap was fantastic and very reassuring. RRS Autobiography P440e

Thanks for letting us know, its an iteresting fault, I will take my jump starter out of the boot now.  2022 P510e RRS AB Frenze Red
2021 BMW i3