Resources Contact Us Home
Battery charge monitor and fuel gauge

Image Number 7 for United States Patent #5315228.

A battery charge controller and fuel gauge which accurately monitors the voltage, temperature, and charge and discharge current of a rechargeable battery, and calculates the battery's charge capacity and charge level. Each time the battery is fully discharged, any calculated charge level remaining is divided by two and subtracted from the previously calculated charge capacity. When the battery is fully charged, the charge level is set equal to the charge capacity. During subsequent charge and discharge, the current is converted to a coulomb count and added or subtracted from the charge level to maintain an accurate charge level. Fast charge inefficiency due to temperature is considered by subtracting a temperature proportional factor before the charge level of the battery is updated. The charge level, voltage and temperature are used to determine the optimal fast charge termination point to achieve full charge and prevent temperature abuse and overcharge. A fast charge is applied only if the battery is within proper voltage and temperature ranges. The charge controller includes a microcontroller circuit within the same battery pack as the battery, which is powered by the battery when AC power is unavailable. The microcontroller circuit consumes very little power, measures circuit errors to assure data accuracy, times periods of self-discharge and updates the charge level accordingly. The microcontroller circuit also includes memory to store the battery charge information and a communication port to provide the charge information to a computer system connected to the battery pack.

  Recently Added Patents
Dual use photovoltaic system
Liquid dispensing apparatus
Information storage medium, reproducing method, and recording method
Processing abstract derived entities defined in a data abstraction model
Eyeglass component
Vehicle inertial sensor systems
Malicious attack detection and analysis
  Randomly Featured Patents
Dense trench MOSFET with decreased etch sensitivity to deposition and etch processing
Terrestrial concentrator solar cell module
Oil shale extraction process
Data card and method of manufacturing same
Light emitting device and illumination apparatus including same
Methods and apparatus for conducting electronic transactions
Fencing tape with electrically conducting wires
Current supply release system for magnetic mechanism
Method for screening restriction endonucleases
Memory cell that employs a selectively fabricated carbon nano-tube reversible resistance-switching element formed over a bottom conductor and methods of forming the same