Car / Truck battery checker.

Discussion in 'The Projects Forum' started by ngaiseng, Nov 13, 2008.

  1. ngaiseng

    Thread Starter New Member

    Oct 20, 2008
    8
    0
    Hi,

    Greeting to all,

    With your help and guidance, I would like to build a 12v/24v lead acid on board monitoring circuit that manages the heath of our vehicle batteries.

    The idea is that the device should regularly check the health of the battery and the vehicle alternator everytime the engine is cranked and after something like 30 seconds or so, go back into sleep mode only drawing minimum current. Should an error be detected ie. Alternator not working it would make an audible sound to inform the driver that a failure is detected.

    A separate switch should be present to monitor the battery health when the car is not started.

    Are there any schematic that does a similar function around as I have not seen anything like this yet.

    Hope to hear from you.

    Thanks.
     
  2. beenthere

    Retired Moderator

    Apr 20, 2004
    15,815
    282
    A voltmeter will show you if the alternator is producing enough voltage to force a charge into the battery. An automotive ammeter that deflects positive and negative away from 0 will establish if the alternator is able to keep up with demand. Neither instrument loads the electrical system, especially is you remember to place the voltmeter across a switched portion of the electrical wiring so it's out of circuit with the key off. It may be 1920's technology, but it works.
     
  3. ngaiseng

    Thread Starter New Member

    Oct 20, 2008
    8
    0
    Hi beenthere

    A voltmeter would work fine no doubt, but I was thinking of a dedicated circuit inside the vehicle that actually warns the driver when the alternator or battery is getting weak.

    Gadgets like this saves people time, money and more important save the embaressment of a breakdown.

    Actually, my idea would be something like a circuit that detects a sudden drop of voltage when the engine is being cranked, take the reading starting from the point the voltage drops and getting the alternator reading for 30 seconds or so using a 555 timer ic. Then a separate button to check the battery power when the car is in stand still. All this warnings will be done using LED's and buzzer.

    Then, comes the hard part..... I have no hoot on how the schematic will come out : (

    Best Regards.
     
  4. ngaiseng

    Thread Starter New Member

    Oct 20, 2008
    8
    0
  5. thingmaker3

    Retired Moderator

    May 16, 2005
    5,072
    6
    I've owned cars with said meters in the dashboard. They had red areas on them to warn me if/when the readings were out of spec.
     
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