Low Power LED Battery Voltmeter


Posted on Feb 5, 2014

This is a low power voltmeter circuit that can be used with alternative energy systems that run on 12 and 24 volt batteries. The voltmeter is an expanded scale type that indicates small voltage steps over the 10 to 16 volt range for 12 volt batteries and over the 22 to 32 volt range for 24 volt batteries. Power consumption can be as low as 14mw wh


Low Power LED Battery Voltmeter
Click here to download the full size of the above Circuit.

en operated from 12V and 160mw when operated from 24V. It is possible to set the meter to read equal steps across a variety of upper and lower voltages. The meter saves power by operating in a low duty-cycle blinking mode where the LED indicators are only on and consuming power briefly during a repeating 2 second cycle. The circuit may be switched to a high power mode where the active LED stays on at all times. Different colored LEDs may be used for the voltage level indicators, this allows the battery state to be read in the dark. With the new blue LEDs, it is possible to have a nice looking rainbow of colors using two each of red, amber, yellow, green, and blue LEDs. The circuit will also work with inexpensive and common red LEDs. If the circuit is to be used in sunlight, ultra-bright LEDs should be used, although even those may be hard to read without some kind of sun shield. The heart of the circuit is the LM3914N dot-bar volt meter IC, U2. This chip is operated in the expanded-scale mode so that the circuit responds in the 10-16V range. U2 outputs a steady voltage on pin 7 from the internal voltage reference. This is fed via voltage dividers VR2 and R5 to the internal reference input pins to set the range that the meter is sensitive to. The measured voltage is fed in on pin 5 via the voltage divider consisting of R4 and VR1. This divider scales the input voltage down to a range that is useful to the IC. The U2 positive...




Leave Comment

characters left:

Related Circuits

  • New Circuits

    .

     


    Popular Circuits

    Digital weight scale
    10M Dsb Qrp Transmitter With Vfo Circuit
    15W Inverter Circuit 12VDC to 120VAC
    33v and 5v dual tracking regulator using lt3692 dc converter
    USB powered device with multiple Decoupling Capacitors
    Microphone Mute circuit
    50hz accurate oscillator circuit
    central locking interface
    dvi to par digital video interface with lcd
    Four phase stepper motor drive system
    Nickel-cadmium battery fast charger temperature control circuit



    Top