If you want to know if the battery is good, just look at the serial number on the battery. Is there any after-sales or spare label on it? Some have stickers on it. If so, it is not new. For the battery, you still need to look at the production date. Look for a set of numbers on the battery. As long as the date on the battery is not different from the date you bought the car by one month, it will be fine. When it comes to battery after-sales, all batteries are guaranteed for 15 months