The activation of the energy economy mode depends on the factors below for example:
- Duration of the "engine running" status
- Battery charge status
- Battery temperature
- Estimated battery charge at the next start-up of the internal combustion engine
- Duration of immobilisation of the vehicle
Each time the vehicle switches to engine running, the BSI resets the internal counter which ranges from 5 to 35 minutes depending on the vehicle parameters and status.
When the engine is switched off, the countdown timer commences for as long as the low speed CAN is active or parking lamps are on.
The counter stops either when the counter reaches 0 or when the low speed CAN becomes dormant.
The battery charge status unit also plays a large role in monitoring the battery health and on vehicles with this system can tell the BSI when to shut off power.
I rarely got 5 minutes with my X7, regardless of battery condition, so put it down to all the electrics (welcome function - electric seats moving back and forward without engine running when entering or leaving car), the TPMS monitoring when the car is stationary, the head unit fan cooling the system after switching off the car, the mirrors folding / unfolding when locking / unlocking, the locking and deadlocking, the EGR self-cleaning etc. etc. and then the alarm and the RCD circuit waiting for a remote unlocking request, then the ECUs writing their data back after ignition off, the suspension pump and height correction when unlocking loading / unloading the car with the engine off.
So I just ignored it - and rarely used the telematics with the engine off anyway.
I put it down to the system on the X7 as many people seemed to suffer similar issues. But 5 years seems to be about your lot with modern cars - but the correct battery is also key. I won't be getting any more Bosch AGM batteries that's for sure, having had 2 of these brand new on several C5s, they're not really up to much. YUASA seem to be rock steady and I will be replacing our Aircross battery with one as the supplied OEM battery fails to work with Stop Start from the outset - or if fully charged, maybe for 2 stop / start cycles then it won't operate any more. What does that say!