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DIY Hobby projects, diagram, schematic

Electronic Circuits

DIY Hobby projects, diagram, schematic

LM3914 12V Battery Monitor Circuit

electronicecircuits, August 5, 2010August 15, 2023
LM3914 12V Battery Monitor

LM3914 12V Battery Monitor Circuit

This bar graph LED battery level indicator circuit is based on LM3914 monolithic IC from National Semiconductor that senses the voltage levels of the battery and drives the 10 light emitting diodes based on the voltage level that is detected.

LM3914 12V Battery Monitor Circuit

PARTS LIST
R156kΩ
R218kΩ
R33.9kΩ
VR110k Preset
D1 – D10LED
IC1LM3914

To calibrate the circuit it must be connected to an adjustable regulated power supply.
Connect an input voltage of 15 volt between the positive and negative poles and adjust the 10K preset until Led 10 lights up. Lower the voltage and in sequence all other Led’s will light up. Check that Led 1 lights up at approximately 10 volts.

This circuit to your own needs by making small modifications. The circuits above is set for ‘DOT’ mode, meaning only one Led at a time will be lit. If you wish to use the ‘BAR’ mode, then connect pin 9 to the positive supply rail, but obviously with increased current consumption.

The LED brightness can be adjusted up- or down by choosing a different value for the 3K9 resistor connected at pin 6 and 7.

You can also change the to monitoring voltage level.

For example, let’s say you wanted to change to 12 – 15 volt,
Remove the R2 resistor and connect 15volt to the input (+ and -) and adjust the 10K potentiometer until Led 10 lights up. Connect  200 Kilo-ohm potentiometer at pin 4 and -. Reconnect a voltage from 12 Volt to the input. Now adjust the 200K potentiometer until Led 1 lights up. When you are satisfied with the adjustment, feel free to exchange the 200K potentiometer with resistors again.(after measuring the resistance from the pot, obviously).

LM3914 12V Battery Monitor test circuitLM3914 12V Battery IndicatorLM3914 12V Battery indicator test circuit

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Comments (40)

  1. WP Themes says:
    August 10, 2010 at 12:57 am

    Genial post and this mail helped me alot in my college assignement. Say thank you you as your information.

    Reply
  2. Potentiometer says:
    August 10, 2010 at 9:20 am

    Thanks for posting, i learn more knowledge on electronics equipment and their uses. As i plan to set up mine but don’t have enough knowledge. At this time i do research more and more to learn everything. Good thing you have posted it. Have a great day! 🙂

    Reply
  3. NitroNick says:
    October 29, 2010 at 11:35 pm

    Just want to say thanks for this circuit! I have a Radio Controlled Boat that I use for fishing and wanted a way of monitoring the battery and this little baby was spot on. Brought parts from Maplins for around a tenner.

    Reply
  4. jim says:
    January 30, 2011 at 12:28 am

    hi , thanks a lot for this circuit it’s very useful ,
    I just want to know if I can modify it for my 24Vdc
    I have a 24Vdc and 12Vdc cigarette lighter in my CAB truck SCANIA , but I use a ( 0-30Vdc , 10A ) regulator
    for my LAPTOP so I need the 24Vdc plug , that’s why
    I need a 24Vdc discharge battery warner
    thanks nice time

    Reply
  5. Mustra says:
    March 11, 2011 at 12:56 am

    Hi, im a newbie at this and i need a monitor for my 4.6V dc battery from my cellullar that now has a different use. is there something special i should do for that circuit to work with my battery?

    Reply
  6. khaled says:
    May 18, 2011 at 9:24 am

    i made this cercuit. But four Red LED could not light up……..why?

    Reply
  7. khalid says:
    May 19, 2011 at 9:47 am

    i made this circuit but four Red LED could not light up……….why?

    Reply
  8. peter says:
    May 23, 2011 at 12:54 am

    Thanx for the circuit,i needed it for a baitboat i made and i want to check the 12v battery i am using.

    Reply
  9. Irfan says:
    June 13, 2011 at 8:37 pm

    Hey – Thanks for the diagram. I’ve made this up and working perfectly for my 12v and 6v battery monitering.

    Its pretty simple and well elaborated by the Author. GOOK WORK!!!

    Reply
  10. Ankit says:
    October 11, 2011 at 7:14 pm

    I have used R1=56K ohm,R2=33K ohm & R3=1.2K ohm.
    Whenever I test a battery either 9 V or 3.7 V , then it always glows 9th LED.Why so?

    Please feel free to tell me

    Please if any one knows the answer,tell.

    Reply
  11. lanre says:
    March 22, 2012 at 8:34 pm

    Please,
    Can you build the types that can use 7 segment display instead of leds.
    Thanks,
    lanre

    Reply
  12. VAMSI says:
    July 25, 2012 at 6:23 pm

    i need equivalent ic for ic LM3914………………..

    Reply
  13. Rob says:
    October 27, 2012 at 5:48 pm

    I would like to make this also for monitoring my baitboat
    Can you tell me the watt of the resistors please
    Many thanks

    Reply
  14. monir101 says:
    December 28, 2012 at 12:36 am

    REALLY IT WORKS . BUT WHY SHOULD RE-QUERIED MORE LED.

    Reply
  15. usama says:
    December 29, 2012 at 8:48 pm

    how to connect the terminals of |VR-1

    Reply
  16. gaz says:
    May 23, 2013 at 12:23 pm

    thank you sir for this information
    please can you help me to realize this project with 120V??
    all my regards sir

    Reply
  17. jcruze057 says:
    October 3, 2013 at 6:30 pm

    hi, I am planning to build this to monitor my battery bank 12v 170ah, is it possible?

    Reply
  18. Marco says:
    October 16, 2013 at 5:23 am

    Hi i cant find the lm3914. Cut be posible use the lm393n?

    Reply
    1. admin says:
      October 16, 2013 at 7:30 am

      You can’t use lm393n. It is a Dual Differential Comparator. Actually this type circuit can build up using comparators. But the circuit is more complicated. You can use this LM3915, LM3916, NTE1508 or NTE1549 alternative ICs. But circuit must slightly change.

      Reply
      1. Marco says:
        October 16, 2013 at 5:05 pm

        Thanks!!!

        Reply
      2. Marco says:
        October 16, 2013 at 5:09 pm

        Could you help me, I’m not electronic but I need this indicator for my battery bank
        Thanks

        Reply
      3. Phil says:
        May 8, 2015 at 11:30 pm

        Hey Admin, thx for your nice work, I really appreciate it!!
        Could you tell, what in the circuit has to change, when it comes to LM3915?

        And what about the potentiometer, is there a way to skip the calibrating part and directly use a resistor instead? How many Ωs would it need?

        Thanks for your work, man!

        Reply
        1. Phil says:
          May 8, 2015 at 11:35 pm

          And one more question: what do you need the R1 for? What would happen, if there was no connection between pole 3 and – …and only a resistor between pole 5 & 3 ?

          Cheers!

          Reply
  19. leela sai madhav says:
    March 23, 2014 at 3:01 pm

    i want to monitor the voltage level of a 24v battery its peak voltage is 27.2 and lowest voltage may be 22.5volts please give me resistance & variable resistance values please

    Reply
  20. ashraf awad says:
    July 14, 2014 at 6:58 am

    i am really happy by this circuit, its very sample and useful for my project . i am thank for your .

    Reply
  21. Rob s says:
    November 20, 2014 at 8:59 am

    a 12v battery has a Maximum operational voltage of 13.6v – 13.8v with a minimum of 10.5v. if you tell the circuit to read a max of 15v and a min of 10v you’ll get wrong info on the batterys health.

    Reply
  22. Rob Sherwood says:
    February 11, 2015 at 11:53 am

    Just a small note about “12Volt” batterys. The typical lead acid battery which includes the traditional flodded and the various gell types. I am not including the more expotics like Li-on and its different fmilies because they require different charging regiment.
    A 12 volt battery is NOT 12volts. It has a voltage range from 10.5v to 13.8v.
    any voltage outside these ranges do nothing but damage them through sulfation and overcharging. Both of which can be easily spotted. Sulfation will appear like a growth on the plates, while overcharging will boil off the electrolyte creating hazardous hydrogen gas. Having a lead battery freeze is no fun either. When that happens you basically have a paper weight with a bulged, and, or, cracked case.

    Lead acid batterys M U S T be kept at full charge at all times. period!

    Lead acid batteries creat sulfate crystals during dishcharge and they attach them selves to the plates increasing their resistance and directly reducing their capacity.
    Removing these crystals can be time consuming and mildly epxensive.
    The simplest way to prevent them from premature death is to get a Proper 4-stage charger, that will charge them properly and keep them full and healthy.

    Thanks
    Rob

    Reply
  23. Rob Sherwood says:
    February 11, 2015 at 11:55 am

    the reason i came here is because i am looking to hook up a 3914 so i can monitor my 36v battery pack (30-42v actually), but the pdf data sheets are terribly vague.

    any thoughts ?
    thanks
    rob

    Reply
  24. darrian says:
    March 16, 2015 at 3:08 am

    can this circuit be edited to handle 24 volts

    Reply
  25. xyzzyx says:
    March 22, 2015 at 6:59 pm

    Hi.How to do it for 48V battery?

    Reply
  26. Kamas Gratuit says:
    March 28, 2015 at 8:54 pm

    Everything is very open with a precise clarification of the issues.
    It was definitely informative. Your site is very useful. Many thanks for sharing!

    Reply
  27. hera gsm says:
    March 30, 2015 at 12:29 am

    i like it.& i love you.

    Reply
  28. aditya says:
    April 22, 2015 at 8:03 pm

    hey can u plz explain me the proper working principle of this circuit using IC lm3194

    Reply
  29. ANTHONY says:
    April 24, 2015 at 8:01 pm

    I made this and it turned out fine. I have calibrated using my solar batteries when fully charged. I will adjust to 15v when I get my variable power supply working. I like that this circuit not only gives me an indication of my battery status but also a visual indication when I am using something that draws a lot of current like a squirrel cage fan.

    Reply
  30. Tran says:
    April 28, 2015 at 5:54 pm

    Hello! if I used 6v/4.5Ah battery, do I need to change anything in the circuit?
    Thank you!

    Reply
  31. Mohammad says:
    May 1, 2015 at 10:53 pm

    Hifirends.thanksfor circuit

    Reply
  32. ANTHONY says:
    May 4, 2015 at 7:19 pm

    I made this. I find it is extremely sensitive and that it gives me a good indication of voltage drop, especially on heavy battery loads.

    I use it in place of the voltmeter I made to show me solar power input and battery voltage.

    Now all I need is a box to put it in.

    Reply
  33. zelyn says:
    May 8, 2015 at 10:16 pm

    hi. can i ask a question? if it works at 24v sir? asap .. just for my thesis

    Reply
  34. imam farid says:
    May 25, 2015 at 9:02 am

    asa,you don’t show any where the wattage of resister.confussion.

    Reply
    1. admin says:
      May 25, 2015 at 9:30 am

      All resistors should be 1/4 Watts.

      Reply

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