The Action Trackchair uses and comes equipped with two 12 volt AGM wheelchair batteries because they excel in high current, high power and in extremely cold environments. Replacement batteries can be purchased at a local Batteries Plus store. Model Numbers are found on the top of each battery. The life of the batteries typically ranges from 18 months to 3 years, but varies from user to user. **TIPS** – Make sure you purchase the exact same batteries, with the posts in the same place. Take pictures of how the batteries are hooked up BEFORE removing.