The present invention provides a power converter for recreational vehicle (RV) batteries that uses time and ambient temperature to control output voltage. By employing a remote temperature sensor attached to the battery post, temperature information is sent to an output voltage control circuit in the power converter. When the power converter is powered up an internal timing circuit increases the output voltage by a preset amount for a timed period for rapid charging but is also adjusted to predetermined temperature curve controlled by the remote temperature sensor to prevent overcharge. The output voltage is held at the increased value until the internal timing circuit times out and the output voltage is reduced (setback) to the float voltage determined by the remote temperature sensor.