Abstract: A power supply is provided with a predetermined nonlinear temperature coefficient for float charging sealed lead-acid batteries and providing power to a load. A temperature compensation network in the power supply provides the predetermined nonlinear temperature coefficient by using a linear temperature coefficient element (forward biased silicon diode) and a nonlinear temperature coefficient element (thermistor) in combination. Additionally, an over-voltage protection circuit, to disable the power supply should the output voltage exceed a predetermined value, is disclosed having a second temperature compensation network to compensate for the output voltage variation with temperature of the power supply.