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
Electric vehicle supply equipment having a socket and a method of charging an electric vehicle
Cell reselection and handover with multimedia broadcast/multicast service
Edge alphas for image translation
Use of LPA for encouraging pregnancy, and fertility agent
Method and apparatus for compensating QoS during handover by base station in wireless broadband access system
Spin transition material
  Randomly Featured Patents
Sink bowl
Multicompartmentalized transdermal patch for administering drugs to the skin
Tone canceller for QAM demodulator
Gallium-containing zeolite MCM-22
Treatment of water-containing coal
Antimicrobial fiberglass reinforced plastic composite
Synergistic mixture of three pyrethroid series insecticidal compounds
Management of protocol information in PNNI hierarchical networks
Method and apparatus for importing data into program code
Pesticidal toxins