Microprocessor controlled battery chargers are the latest

IC Timer Controlled Battery Chargers: IC just stands for Integrated Circuit, in which timing is monitored by a silicon chip. Timer batter chargers has the same output similar to simple chargers but they charge in less than half the time of manual chargers and output is ceased after a pre-determined time. However, they are not suitable for top-up charging and they may overcharge because they can't determine the initial of batteries. This means that if a battery has already been fully or partially charged, IC timer controlled battery chargers will still try and charge batteries for the full duration of its timer. In order to combat this complication, some of them have "overcharge protection" sensors.
Intelligent or Microprocessor Controlled Battery Chargers: When a specific voltage is reached, a microprocessor controlled battery charger is able to determine when to stop fast charging and then "trickle charges" the battery. Not only that, it also monitors temperature and time under charge to determine the optimum charge current at that instant. This implies that batteries in any charge state can be fully charged in less then about 3 hours without risk of overcharging, because termination of the charging is based on the combination of the voltage, temperature and time indication.
Microprocessor controlled battery chargers are the latest, safest and most efficient battery chargers today."Fast charging" refers to the rapid charging of batteries fully, usually within one to three hours. This may result in shortened life or reduced capacity if current is not controlled. "Top up charging" means charging a re-chargeable battery before it has been completely discharged.