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Electrical scooter having an equalization circuit for charging multiple batteries

  • US 5,965,996 A
  • Filed: 12/11/1997
  • Issued: 10/12/1999
  • Est. Priority Date: 12/11/1997
  • Status: Expired due to Term
First Claim
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1. An electric scooter comprising:

  • a plurality of series connected batteries, each battery having a first and a second terminal and a battery voltage across said terminals;

    an equalization circuit arranged to distribute current among said plurality series connected batteries during a constant current charging phase, said equalization circuit comprising;

    a plurality of cell circuits, each cell circuit being connected across the terminals of a corresponding one of said plurality of batteries, each cell circuit havinga first detector circuit arranged to detect a low voltage condition wherein the battery voltage is lower than a first predetermined value,a second detector circuit arranged to detect a high voltage condition wherein a detected voltage is higher than a second predetermined value, said second predetermined value being greater than said first predetermined value;

    a first switch arranged to enable both of said first and second detectors in response to an external signal;

    bypass circuitry arranged to bypass a charging current around the corresponding battery after detection of said high voltage condition; and

    a second switch arranged to output a status signal signifying detection of either a low voltage condition or existence of a current bypass condition wherein a current flowing through said bypass circuitry exceeds a predetermined amperage;

    a first logic circuit having an output providing a first signal when any one of said second switches outputs a status signal signifying a low voltage condition; and

    a second logic circuit having an output providing a second signal when all of said second switches output a status signal signifying existence of said current bypass condition; and

    a controller electrically connected to each of said first switches to selectively provide said external signal, wherein said controller provides said external signal in a first mode to detect a low voltage condition, when said scooter is being operated,said controller provides said external signal in a second mode to detect the existence of said current bypass condition, when said series-connected batteries of said scooter are being charged, andwhen the controller is in the first mode, the controller intermittently provides said external signal.

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