I have a Hubin/Brodak set up and I get in two flights, one right after the other. Land change batteries and go. The first flight gives me 5 or so laps after the pattern, as it should, the second maybe a lap or two. It's the same each time out. Should I wait longer between flights or is the esc crapping out?

Are the lap speed the same on both flights? 

It's a little late but it's been raining here in Denham Springs, La.  I took the two batteries, they are numbered, and charged them by switching charging stations. #3 in station 4 and #4 in station 3. At the field this morning I flew the #4 battery first, which I always flew second, and got 5 min. 42 sec. from pushing the start button to motor stop. Enough for the pattern and 6 or 7 laps extra. Then I flew the #3 battery and got exactly the same time with extra laps. Changing charging stations seemed to do the trick.The batteries could be still forming also.