I haven't seen a bump box used for a while. Ideally, a single charge peaked right before you go out to race is the best. Keep in mind how long it takes to get through tech when calculating charge time. Re-peaking batteries is not ideal, but if a race drags out and your cells peaked, may be necessary. Re-peaking at a high rate will drive up the voltage. However, the first turn you severely hammer the pack (wall hit, or even hard on the throttle) that peak will be lost.
Most times, especially at club races, people will perfect peak, then drive the car around the track to trim in the car. This will take the top off a peak, although usually doesn't hurt the duration of the race perceptibly.
Speed Merchant Rev7, Tekin, TQ Racing (wire), Team Tamale
RC Excitement - Buy where you race, support your local tracks.