Abstract: A universal interface plate has a predetermined and universal configuration suitable for connecting any one of a plurality of types of rechargeable batteries to the circuitry of a charging device. The universal plate is adapted to any type of rechargeable battery using an appropriate bay adapter, the bay adapter including a first interface for mounting the bay adapter to the universal interface plate and a second interface for accommodating a particular type of battery. The charging device utilizes a ramping charge method whereby batteries are initially charged at a low charging rate, thereby allowing safe charging of low and high capacity batteries utilizing a single charging algorithm. The charging rate is increased incrementally after determining whether the incremental current increase would cause the power to the battery to exceed the maximum power that can be handled by the bay.