I have two EP 4200 sets from pro match. I treat them the same as the IB, keep them charged up during storage, over 1 week full charge.
I spintec discharge them. then equalize them on a novak smart tray then charge them up for racing.
the instructions said you can charge them twice after they cool for a couple of hours.
I tested charging the pack twice on the spintec discharger and it indicated the pack had more voltage on the second charge. this varied but generally the second charge produce more voltage than the first upon discharge.
I tested the first pack during practice last week end and it was ballistic. from my estimation the second charge had even more punch. The second charge felt faster, however I don't have print outs to prove that lap times were any faster.
so far I really like the EP's
however I am waiting until next year, I wll go to lipo, it seams that is the direction or then again I will get the next EP4600's I hope they will fit into my car. I had to dremel my tA05 to get the 4200's to fit!!!