Acid Lead Battery Charging

Discussion in 'The Projects Forum' started by cametolearn, Nov 18, 2008.

  1. cametolearn

    Thread Starter New Member

    Nov 18, 2008
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    Hi...can any one please help me with this problem?...I have a battery in consideration..It is an DC Acid Lead Sealed Gel battery..12V DC..the amps per hour is 4Ah....what i want to do is when the battery is being charged..how can i find that out using a comparator when the battery is fully charged and when it is, switch the incoming supply to a Dump(some load)....If you want more details about the project let me know...thanks in advance mates
     
  2. iONic

    AAC Fanatic!

    Nov 16, 2007
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  3. cametolearn

    Thread Starter New Member

    Nov 18, 2008
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    Hi ionic...thanks for the reply...im confused...sorry ill be more specific...the thing is that Im making a controller, which has two Outputs...the Input is regulated 12V DC....out of the two controller Outputs is a Sealed Lead Acid Battery and the second output is a Dump (12V DC Load)....My primary aim is to charge the battery and when it is fully charged i want the controller to switch the link to the dump and when the battery starts discharging, the controller should switch back to the battery....so im after a controller which will do the above procedures...but as im really interesting in a comparator, can you help me with that....but if you think that comparators wont be suitable can you advise me on other components like mosfets etc....also if you think that micro controllers are useful in that case for directing the voltage to either of the outputs..How can i go about detecting a full battery charge or battery discharge to the microcontroller so it does the operation?...sorry for this long problem...im just a new learner and really confused with this project....and im not so good at electronics...thanks again....
     
  4. SgtWookie

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    Jul 17, 2007
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  5. iONic

    AAC Fanatic!

    Nov 16, 2007
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    First off, I'm not the most reliable source for your electronics learning, but I try anyways and do offer some direction at least.

    Do you already have a charge controller for charging with Solar or Wind energy? Is this how you plan on charging your battery?

    Without knowing I can suggest googleing for "Charge Controller" or "Dump Controller"

    Below are two sites, one for a charge controller(don't think it includes the dump control circuitry, but rather just reverts to a safe float charge to protect battery overcharging), the second is a dump controller, diverting unneeded charge current to another device such as hearing water, operating lights...etc.

    Charge Controller

    Dump Controller

    As far as comparators and micro controllers are concerned I'm sure it can be done with either of them. With respect to micro controllers, if you do not have the programming experience it will be a long road to project completion.



     
  6. cametolearn

    Thread Starter New Member

    Nov 18, 2008
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    Hi again...No I dont have a charge controller at the moment and that is the thing im trying to build and use....Yes im using a wind turbine and a solar panel...but currently using variable power supplies for initial purposes and testing...im using an adjustable voltage regulator which i constructed using an LM7805 CT regulator.....so after combing the two in one point i can get 12V DC....the next thing is the Charge controller which you correctly mentioned along with a battery and a dump...but i think what i might need is a dump controller....what ill do is ill have a read through it and then contact you if i need more directions.....also can you give me an idea or direction to how i might be able to use comparators in this regard....thanks a lot with the help mate
     
  7. cametolearn

    Thread Starter New Member

    Nov 18, 2008
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    thanks for the link mate but i am not up to the standards in programming....
     
  8. SgtWookie

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    Jul 17, 2007
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    The LM7805 is a fixed 5V 1A regulator. It can be adapted to use at higher voltages by adding resistance from it's ground terminal to GND (nominally 200 Ohms per volt increase over 5v) or by giving it a different voltage reference, such as an output from an operational amplifier.

    If this is your first project, you'd be best off by building a kit.

    Attempting to use just a single comparator to control charging would be an over-simplification of what needs to be done. There are several different phases of charging; the bulk charge period, final charge period, float charge, and occasional leveling (overcharge) period to stir the electrolyte. These all require different levels of current for the battery voltage and temperature.

    It's a pretty involved project for a beginner.

    Check out this technical note on temperature compensated battery charging:
    http://rep.mgeups.com/edg/edg/technote/battch.pdf
     
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