Battery-powered tools may include battery 1 or battery pack BP and a drive source (e.g., motor M) for generating power using current supplied from the battery. A switch 3 may electrically connect the battery to the drive source. A voltage detector may dete...

When rechargeable batteries have been discharged to a selected voltage reference level, LED 29 (and/or buzzer BZ) and controller 32 may warn the operator that the rechargeable batteries should be recharged. Controller 32 may change the selected reference v...

A plurality of charging devices 30 may be connected to a computer 10, 110 via a network 60. When computer 10 receives charging information from a charging device 30 before performing a charging operation, computer 10 may compute the optimal charging period...

Connecting to a home page via the Internet, selecting the mode of use of the battery desired by the user, downloading the charging characteristics which match the selected mode of use, and reading the charging characteristics into a EEPROM of charging devi...

In a battery charging device(10)capable of detecting abnormalities in cells comprising batteries through a simple arrangement and terminating charge accordingly, cell temperature information Ta and cell temperature information Tb in charging operation with...

Charge is performed while restricting rises in temperature of batteries by maintaining the rise in temperature constant, and charge is terminated when the current value becomes not more than a specified value indicating completion of charge, when the tempe...

Hysteresis is stored when charge has been started in a condition in which the battery temperature is high and the capacity is large; upon judging whether such charge has been frequently performed, if it has been judged that the frequency is high, a pattern...

The battery charging device obtains an open-circuit voltage at the time of 70% capacity based on information stored in a ROM of a battery package prior to the charge, and upon measuring an open-circuit voltage of the battery package by a voltage measuring ...

Rotation of an air-blowing motor is continued also upon completion of charge; by retrieving a presumed temperature for cooling and upon detecting that a measured temperature is higher than the presumed temperature for cooling by not less than a specified v...