Abstract: A battery charger for charging one or more rechargeable batteries. One or more rechargeable batteries are placed into one or more charging areas of the battery charger. Each of the one or more charging areas has a positive charging plate and a negative charging plate and is configured to receive a battery. The battery charger includes a charging circuit coupled to the positive charging plate and the negative charging plate of each charging area, the charging circuit configured to provide a charging current through the positive charging plate and the negative charging plate of each charging area, the charging circuit further including a microcontroller configured to receive a detection signal and adjust the charging current in response to the detection signal. In one embodiment, the battery charger detects the presence of an AAA size battery and adjusts the charging current.

Abstract: A battery charger includes a housing for accommodating batteries to be recharged, and a plurality of charging channels, each configured to charge batteries of different sizes. Electrical connectors are located within the housing for receiving one or more batteries in each of the charging channels. A battery size detector detects the size of battery inserted in each channel. The charger further includes electronic circuitry for applying, independently to each channel, charging power appropriate to the battery size detected for the channel.

Abstract: A battery charger having a plurality of series connected sections for serially charging a plurality of rechargeable batteries, for example rechargeable batteries of AA or AAA size. Each charging section includes a charging path for a battery and a parallel bypass path for bypassing a battery when it is fully charged. The charging path and the bypass path of each charging section each include an electrically operable switching device, which devices are preferably MOSFETs. Control circuitry is included to ensure one switching device is off when the other is on. MOSFET switching devices are connected into the circuit in directions to ensure they are not burnt out by the charging currents. A discharge circuit may be included for the batteries to discharge briefly between pulses of charging current thereby providing for “negative pulse charging” of the batteries. The charger provides for improved efficiency of charging in that very little power is consumed by the switching devices in the charging paths.