2nd Concord battery. Have a check done to ensure no parasitic drains in aircraft electric sys. First start of day with ext cart whenever possible. If on 3rd start attempt get ext cart--on average after two attempts lead acid batteries can become permanently tweaked. Don't fiddle with GPS after shutdown, plus any extended drain (eg. fuel valve left on, etc.) will reduce useful battery life. 70 starts in 27 months is not a lot, but that's a long time for a batt to sit without use and installed/connected. Good luck. W1