Power management system

A power management system for managing the power to operate a biomedical device from a rechargeable battery and from an external power source, the biomedical device having power requirements that vary depending on the mode of operation selected, the system comprising:

• connection means for powering the biomedical device from an external power source when said source is connected to the power management system and for powering the biomedical device from the battery when an external power source is not connected to the power management system;
• a charger connected to the battery to provide charge to the battery and to deep discharge the battery in response to charge control signals;
• a processor having a memory having a value for the charge capacity of the battery stored in the memory that:
• provides a charge control signal to the charger to cause the charger to provide charge to the battery when an external power source is connected to the power management system;
• automatically adjusts the value for the charge capacity of the battery stored in the memory based on the number of discharge/charge cycles undergone by the battery;
• automatically monitors battery usage to power the biomedical device;
• automatically calculates a value for the amount of charge in the battery based on the value for the charge capacity of the battery stored in the memory and automatically updates said value for the amount of charge in the battery based on battery usage;
• automatically calculates the run time of the battery based on the calculated value for the amount of charge in the battery and the present power requirement of the biomedical device in the selected mode of operation and automatically updates that run time as the value for the amount of charge and the power requirement of the biomedical device change;
• provides a display signal representative of said run time;
• and
• a display that displays the determined run time in response to the display signal.

A method of managing the power for a biomedical device that is connectable to an external power source and which has an internal rechargeable battery, the biomedical device having a power requirement for operation, the method comprising the steps of:

• powering the biomedical device from the external power source when the external power source is connected;
• powering the biomedical device from the internal battery when the external power source is not connected;
• recharging the battery to full charge when the external power source is connected;
• automatically determining the charge capacity of the battery based on the number of discharge/charge cycles undergone by the battery;
• automatically determining a value for the amount of charge in the battery based on the determined charge capacity of the battery;
• automatically determining the run time of the battery based on the determined value of the amount of charge in the battery and the power requirement of the biomedical device;
• and
• displaying the amount of run time for the battery.

A power management system for managing the power to operate a biomedical device form a rechargeable battery and from an external power source, the biomedical device having a power requirement for operation, the system comprising:

• a charger connected to the battery to provide charge to the battery in response to charge control signals;
• an ambient temperature sensor providing an ambient temperature signal;
• a processor that automatically controls the charger to charge the battery:
• in a fast charge cycle in which charge is applied to the battery at a rate that will cause battery damage unless the cycle is limited in time;
• in a top-up charge cycle following the fast charge cycle;
• in a float charge cycle in which charge lost due to self discharge of the battery is replaced;
• and
• in a hot charge cycle when the ambient temperature signal indicates that the ambient temperature exceeds a first predetermined threshold, wherein the hot charge cycle comprises applying charge to the battery at a reduced level and for an increased period of time in comparison to the fast charge cycle.