If there's a charge in your account that you don't recognize, it might be one of the following:
If you purchased a Single Ride, Day Pass, or Annual Membership, a set length of time is covered with the pass price. If you keep a bike out for longer than 30 minutes at a time on a single ride. With the Day Pass, you can have a single ride continue for up to 3 hours. For Annual Members, the first 45 minutes of each ride is included. For all pass and ride types, there is an extra usage fee of $3 per additional half hour.
Lost bike charge
If you have kept a bike out for more than 24 consecutive hours, it is considered lost or stolen and there is a fee of $1,200 (plus tax). This can also happen if you did not dock your bike properly, so your ride stayed open, and someone else took the bike and has not returned it.