Design of 555 timer based wind/solar charge controller

Discussion in 'The Projects Forum' started by Umar27, Dec 8, 2014.

  1. Umar27

    Thread Starter New Member

    Dec 7, 2014
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    hi guys!! i m working on a project POWER GENERATION USING SMALL WIND TURBINE..
    I have done 90% of the work.. I m using the following components

    =>PERMANENT MAGNET DC MOTOR (max voltage=40V, max current=4.4A, RPM=450)
    =>555 timer based Charge Controller from (mdpub.com/555Controller/)
    =>PVC Blades 1meter radius
    =>14 feet high assembly for elevation
    =>12V 20AH lead acid dry battery

    Every
    thing is ready , charge controller is working fine except the following question which is irritating my mind.. PLZ ANYONE CAN HELP ME OUT THIS

    ....IS it compulsory that battery should be charged with uniform current?? because wind power is always varying that produce varying current!!! my biggest problem is to identify the component in my 555 charge controller that regulates the varying current to uniform to charge the my 12v 18AH battery...(I have made 555 timer based charge controller from mdpub.com/555Controller/... furthur more i have noticed that this charge controller is more of a switching device that switches dump load on and off when required rather than a "CHARGE CONTROLLER").... plz respond!
     
  2. Umar27

    Thread Starter New Member

    Dec 7, 2014
    12
    0
    these are some picture files from my project 555ChargeController2.jpg jh.JPG jhh.JPG
     
  3. Umar27

    Thread Starter New Member

    Dec 7, 2014
    12
    0
    more pic files yu.JPG PB210528.JPG
     
  4. Dodgydave

    Distinguished Member

    Jun 22, 2012
    4,969
    744
    dont know why your using a timer, i would use a simple diode and 14v regulator constant voltage charger, and dont need to dump the solar panel excess volts.
     
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  5. alfacliff

    Well-Known Member

    Dec 13, 2013
    2,449
    428
    uniform charge not necessary, just limit the current to less than the battery max and the voltage to less than the battery max from the specs. most small commercial charge controllers are shunt regulators to prevent overcharging.
     
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  6. wayneh

    Expert

    Sep 9, 2010
    12,088
    3,027
    Not at all. A very common method of charging a lead-acid battery is to use a constant voltage, with a limit on the maximum current. With this strategy, a discharged battery might draw up to the current limit, let's say 10A, when it is first attached to the charger. As the voltage rises the current will fall. When it falls below the 10A limit, the voltage controller takes over and holds the voltage constant at, say 13.8V. The current drops gradually as the battery becomes more and more charged. When fully charged, the battery will draw just a trickle and this is fine for a lead acid battery.

    That's a pretty clever use of the 555 as a comparator. But I think one problem with that controller is that it may oscillate and cause the relay to chatter. There will be very little load on the panel when charging an already-charged battery. So the voltage will be high, and the controller will switch to the dummy load. But that may draw quite a bit of current and bring the voltage down, causing the controller to switch back to the battery again.
     
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  7. Umar27

    Thread Starter New Member

    Dec 7, 2014
    12
    0
    Thanks wayneh for your reply but the voltage output from my wind turbine is constantly varying with the varying wind. I used a LM7805 voltage regulator in charge controller circuitry that just power the circuit.. I m still struggling to find how to make the incoming voltage constant!!!Is there a component in my circuit thats doing this job??I dont know bcoz i just followed Mike Davis Concept(mdpub.com/555Controller/ ) and Controller is just working very fine!!!!
     
  8. Umar27

    Thread Starter New Member

    Dec 7, 2014
    12
    0
    Here is the list of components of 555 based charge controller
    IC1 - 7805 5 Volt positive Voltage Regulator
    R3, R4, R5 - 1K Ohm 1/8 Watt 10%
    IC2 - NE555 Timer Chip
    R6 - 330 Ohm 1/8 Watt 10%
    PB1, PB2 - NO Momentary Contact Push Buttons
    R7 - 100 Ohm 1/8 Watt 10%
    LED1 - Green LED
    Q1 - 2N2222 Or Similar NPN Transistor
    LED2 - Yellow LED
    Q2 - IRF540 Or Similar Power MOSFET
    RLY1 - 40 Amp SPDT Automotive Relay
    C1 - 0.33uF 35V 10%
    D1 - 1N4001 or similar
    C2 - 0.1uF 35V 10%
    R1, R2 - 10K Multi-Turn Trim-Pots
    R8*-R9* - Optional 330 Ohm 1/2 W Resistors
     
  9. wayneh

    Expert

    Sep 9, 2010
    12,088
    3,027
    The voltage at the battery terminals is anchored by the battery. Your windmill might have a 30V emf, but when you attach the battery, that voltage will drop to ~14V and current will be driven into the battery. The AMOUNT of current depends on the mill, the battery, and any circuitry in between. As long as the mill cannot overpower (over CURRENT) the battery and/or circuitry, you don't need to worry about the voltage.
     
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