Yes as above - using the batteries in the car is the quickest (and most fun) way to drop them down, a lot of the time they will be below storage voltage so when putting them on the charger in "storage" they will actually be charging back to 3.8V per cell, rather than discharging.
After a race meeting when I get home I set the charger up and sort all my packs out back to storage.
I charge at least one of mine up late at night the night before a race, as sometimes we have a 2hr drive at 6.30am to get to the track, and I ain't getting up at 4am to charge my packs up!
