A balancing circuits and methods for hybrid batteries having two different rechargeable batteries that are coupled in series includes coupling a fuel gauge to each battery to determine the state of charge of each battery, comparing the state of charge of the two batteries, and if the state of charge of the two batteries is more than a predetermined difference, then enabling a switching converter to source current to a node between the batteries or to sink current from the node between the batteries, as required to tend to equalize the state of charge of the two batteries. Otherwise, if the state of charge of the two batteries is equal within a predetermined allowance, then disabling the switching converter.