XC90 T8 Start Battery Failures...

[carlhunt]

Hi,

I have a curious situation on going with start battery failures in my T8. In December during the cold snap I came to the car to find it dead. Opened the doors, jump started, start battery health looked suspect. Cold weather & 8 year old battery so I assumed it's time was up and purchased a replacement AGM battery.

Two weeks later came out to the car and it was dead again. Charged the battery and all good.

Car went in to the local dealer to have the sunroof fixed two weeks later and at the same time I asked them if they could check the battery/charging system due to what I had seen. They said check on battery fine, all ok. I went to collect the car, paid and they said they would bring the car round to the front. Service manager then appears, embarrassed, as car won't start. Test the battery again, condition poor so this was replaced. I was still concerned but needed to follow the process so took the car home and five days later having sat locked & charging when I went to use it - dead again. Now struggling to charge that new battery.

My belief is that the start battery is charged from the hybrid battery. The only change that occurred about the time that this started was fitment of a new wall charger at home (which has charged the hybrid battery in the T8 and other cars).

So, good people - my questions are

Does the hybrid battery charge the start battery?
Any experience of this hybrid-start battery process failing?
Any ideas of what else could kill off the start battery?
Any possibility that a wall charger (in this instance a Hypervolt Home 3 Pro) could interfere with the start battery (I think I'm clutching at straws with this one)?

Thanks in advance......