I've got a 2017 Malibu LT 1.5 with 45000 on it. with the same factory battery. I've had no problems with it but I'm wondering when I should replace it. I read some posts where owners post the voltage readings but I can't find any way to get them on the cars info system. Is there a way to get them or do I need to check the battery with a meter or should I just replace the 6 year old battery? Thanks...Tony S