[MrM83]

I’m conscious I’m posting similar info on my issue which is touched upon in a number of threads. By posting I always hope that it might be useful for someone in the future who has a similar problem.

To summarise and update on some findings:

- post 12v system service message I connected my CTEK trickle charger via front terminal points under bonnet of my 21 XC90 T8. Indicated state of charge was low and overnight my CTEK was showing a full charge.

- that day I drove ~30 miles mostly in AWF and PE modes and received constant 12v system service requirement messages every few minutes.

- on getting home I plugged my CTEK charger directly to the rear battery and to my surprise was showing as low. Again I left it charging overnight and was showing fully charged by this morning.

- I’ve not received any more error messages all day since directly charging the rear 12v unit. I have purchased an eyelet adapter for my charger with the traffic light system to show state of charge. Curiously after fitting it was showing as amber “in need of a charge”. I got my multimeter out and measured the voltage on the rear battery at 12.54v. 10 mins later it was 12.24v and registering as red on the adapter (in desperate need of charge) which seems really weird, given the car was off, only the boot was open.

- after driving the car in PE mode (deliberately to engage the ICE) for another 20 miles or so the adapter shows green and the multimeter is reading 13.40v across the battery.

I’ve no clue what is going on here, I’ll need to speak to Volvo about it I guess. On the face of it it appears I’m suffering huge battery drain for some unknown reason, enough to go from fully charged via CTEK to ~12.2v in the same day.

If anyone has any ideas I’m all ears.

Thanks