A LOW-BATTERY ALARM FOR 13.6 VOLT LEAD-ACID BATTERIES


Posted on Feb 4, 2014

[The following circuit is adapted from battery monitors and testers published in The Smith-Kettlewell Technical File (SKTF). The first appearance of this system was `The Smith-Kettlewell Battery Tester, Where Silence is Golden`, SKTF, Volume 11, No. 1, Winter 1990. ] The application here was inspired by a request from a visually impaired ham-radio


A LOW-BATTERY ALARM FOR 13.6 VOLT LEAD-ACID BATTERIES
Click here to download the full size of the above Circuit.

operator whose "rig" (transceiver) specifically requires that its supply voltage be above 12 volts under load. When powered by a storage battery (as in emergency operation), his unit would malfunction on transmit, which could not be detected by the operator. Thus, he suggested that a sensitive warning system be devised (other than a multi-digit meter) by which the operator would be alerted to an impending low battery condition. Since the time of that request, we have become interested in providing an alarm for riders of motorized wheelchairs - an audible indicator that would warn the user that he should put a charge on the battery before "deep discharge" damages it. Thus, the values and adjustments shown here are for voltages below 11. 66 volts. Smith-Kettlewell`s "Rehabilitation Engineering Research Center", funded by the National Institute on Disability and Rehabilitation Research, devised a battery-checking scheme which has found its way into several of our designs - a vibratory hearing-aid button-cell tester for the deaf-blind, an auditory adaptation of the Radio Shack "Handy Checker" (see the above byline), and a test instrument for servicing "talking book" players. The principle of our readout is to generate bursts (audio "beeps", or vibratory "buzzes" for those who cannot hear audio signals); their duration indicates battery voltage. (In this implementation, the output is auditory. ) Specifically, an exhausted...




Leave Comment

characters left:

Related Circuits

  • New Circuits

    .

     


    Popular Circuits

    Wireless LCD Display (AT90S2313)
    Robot Beacon with PIC12C508A
    Pulse-width modulator
    Portable Nicad Charger
    Tunable Bandpass Filter
    Android talks to Arduino board
    AVR Interrupts and binary counter
    Home-Built Dye Laser
    lighting leds
    mercury v8 monterey 1963 wiring diagram
    ELECTRONIC COMBINATION LOCK
    DIY Circuit Car Battery Charger
    Electronic energy-saving lamp circuit 3



    Top