An electronic device, such as a radiotelephone, is connectable to a variable-level power source. The electronic device includes a rechargeable power source which is repowered responsive to application of operative power generated by the variable-level power source. The electronic device provides a constant charge current regulator for converting operative power of a constant voltage into operative power of a constant current to be applied to the rechargeable power source to recharge the rechargeable power source. The constant charge current regulator is made up of a series connected diode and resistor pair. According to a further aspect of the invention, when the rechargeable power source becomes fully recharged, application of the operative power can be reduced.