I have a 2015 GLA 4matic that I bought a year ago and has always lived in cold New England. Current mileage is 45k. I have the Auxiliary battery warning. Going to get a new one. Should I go ahead and switch out the main one also while I’m at it. The car is going on 7 years old with the original batteries and feel like that might be the best thing to do. What do you think?