US 9,851,407 B2 · Self heating heater

Abstract

The invention relates to a power management system for supplying backup DC power to peak and/or high current demand battery applications, such as motor starting or an uninterruptible power supply (UPS) used to power a critical load, such as, a data bus or other critical load, after an event, such as loss of primary AC or DC input, during relatively cold ambient temperatures. Two or more heaters can be provided; for example, a low power heater and a high-power heater. In a maintenance mode, the low power heater is used to maintain batteries at a predetermined temperature. In this mode, a battery charger is used to power the low power heater. In a boost mode, after the primary AC or DC input is restored, and battery temperature is too low to back up the critical load, the battery charger supplies power to one or both of the heaters. Since capacity of the battery charger is normally insufficient to heat the batteries to an acceptable operating temperature in a relatively short period of time, a portion of residual power from the batteries is used to boost power to the heaters in order to speed up the time to get each battery of said batteries to its rated operating temperature.

Claims10

Dependent claims

A power management circuit for providing backup power to a critical load during various conditions, the power management circuit comprising:

one or more batteries connected in parallel across a pair of load terminals;
a first switch selectively connectable between said load terminals and said one or more batteries to selectively connect said one or more batteries to said load terminals;
a current sensing resistor connected between said one or more batteries and said load terminals for sensing the charging current and discharging current provided to said one or more batteries;
a battery charger for charging said one or more batteries;
a primary power input terminal connected to said battery charger;
a second switch connected between said battery charger and said batteries to allow said battery charger to selectively be connected to said one or more batteries;
one or more heaters selectively connectable to said battery charger for enabling said battery charger to power said one or more heaters;
a temperature sensor for sensing ambient temperature of the batteries;
and
a computing device for determining the state of charge of the batteries from the charging current, the discharging current and battery voltage, and controlling said first switch as a function of the state of charge of said batteries, said power management circuit configured to enable said battery charger to charge the batteries and power a heater at a same time.

7 more elements

Dependencies are inferred from the claim text.

Self heating heater

Life of this patent

Self heating heater

Life of this patent

Abstract

Claims10