How do I change the battery in my 2011 Acura RDX key? (video)
What kind of battery do I need to replace key fob?
Gently insert a flathead screwdriver into the small slot on the side of the key fob. Twist it to open the key fob. Before you remove the battery, make note of which direction the positive and negative sides face. Carefully slide out the current battery, and replace it with a fresh CR2032 button cell battery. via
How do you change the battery in a 2015 Acura RDX key? (video)
How do I replace my car key fob? (video)