Method and system for charging a NiMH or NiCd battery

A power supply system comprising:

• a power input configured to receive input power from a power source;
• a power output configured to provide power output to at least one of a Nickel Metal Hydride battery and a Nickel Cadmium battery;
• a charger coupled to the power input and the at least one battery, and configured to convert input power to output power to charge the at least one battery;
• and
• a controller, coupled to the charger, configured to control the power output from the charger to the at least one battery based on a measurement of heat generated in the at least one battery, wherein the controller is configured to vary a flow of charging current into the battery proportional to the measurement.

A computer readable medium having stored thereon sequences of instruction including instructions that will cause a processor to:

• receive an indication of a first temperature detected at a point proximal to a battery pack in a power supply system;
• receive an indication of a second temperature detected at a point distal to the battery pack;
• determine a difference between the first temperature and the second temperature;
• and
• vary a flow of charging current into the battery pack proportional to the difference between the first temperature and the second temperature.

A system for charging a battery comprising:

• an uninterruptible power supply having a battery;
• a first sensor configured to detect a first temperature at a point proximal to the battery;
• a second sensor configured to detect a second temperature at a point distal to battery;
• and
• a controller configured to vary a flow of charging current into the battery proportional to a difference between the first temperature and the second temperature.