Battery drain

This morning I went to go meet Jim Gruneiesen, one of the BPPP instructors for some training.  I went to fire her up and the left engine fired up right away, but when I engaged the starter on the right engine the blade basically moved a little bit and then stopped. It was as if the battery was low or dead, but I had the battery tender on and it should have been fine... grrr.  I had been juggling with Jim for weeks and had to cancel. Turns out the batteries had just hit their limit.  This afternoon Chris and Alan from MaintenanceExpress flew over in their 172 from LVK with two new batteries.  They showed me how to change out the batteries and then I fired her up.  She fired up so fast it surprised me. I've never had a plane start so fast, faster than my car.  Back to squawk free for now (knock on wood)!