I got this 2018 GC Limited Sterling edition about 3 months ago, I bought extended warranty on it but I keep seeing the message "stop/start not ready, battery charging" it's been that way for about 3 weeks now. I'm thinking the battery is fried. Anyone know if I can just do a basic aux battery swap without worrying about the ECU and all that? If so...what battery will I need? I know there's a couple different types.