i have 2015 EZGO TXT with original flooded lead acid batteries. In last 2 months it has less get up and go. And needs to be recharged more often. Water is evaporating faster too but it has been a hot summer in garage. Last recharge there was acid spill onto the garage floor even though water levels were at or below 1/4 inch. Checked spec gravity - all but one cell were in the white. One cell was right at border of red. Can Cells be replaced individually or do I need all new battery pack?