help. can anyone suggest a smart, fully automatic car battery charger?

- can charge the battery without removal from the engine bay
- must be able to switch to "trickle charge" mode when battery is fully charged
- can kept plugged into the AC outlet for a long time (24 hours or more) without damaging the car battery
- must support maintenance-free batteries among others
- have safety provisions, e.g. over-current, over-power, over-voltage, over-charge, etc.

please share brand, model, price and store/seller where you got it.