US Patent 7872450 Adaptive battery charging

A system includes an input configured to connect to a power source providing an input voltage, an output configured to connect to a load and to transfer power from the power source to the load, a battery selectively coupled to the input to receive current from the power source, a detector configured to indicate whether the input voltage drops more than a threshold amount, and a processor configured to regulate the selective coupling of the battery to the input to regulate a charging current supplied to the battery, the processor configured to regulate the selective coupling such that if a first charge current induces a drop in the input voltage beyond the threshold amount, then the processor will change the charging current to a second charge current that is lower than the first charge current.