Changing chargers with button

Discussion in 'The Projects Forum' started by liamneeson248, Jan 11, 2016.

  1. liamneeson248

    Thread Starter New Member

    Jan 11, 2016
    14
    1
    i need to charge a lead acid 12vdc battery and for that i need two chargers
    1- 12VDC 4A
    2-12VDC 20A
    first one is for normal charging daily and second one is for fast charging battery once a 4-5 months to maintain its gravity now the problem is that in my setup i need to install both chargers but i dont know how to do switching with a simple switch
    i am attaching diagram which is a rough idea what i need and suggest me any solution
    1111111111111.png
    as you can see in this diagram that i have ofcos one terminal but if i give it 4A it will send it will start charging battery ofcos but on other hand it will give that current back to 20A charger which is also connected to same terminal so what can i do to prevent that or how can i connect these two chargers but also put a button to select my Amperes whenever i want ?
     
  2. mcgyvr

    AAC Fanatic!

    Oct 15, 2009
    4,769
    969
    you could use a DPDT switch
    DPDT=double pole/double throw
     
  3. liamneeson248

    Thread Starter New Member

    Jan 11, 2016
    14
    1
    but the thing is how to stop it from giving that 4a back to other 20a charger ?
    and what if i wanna control it with arduino what will i do then ? i mean in arduino i can only use relay to change switching.
    how will i put two relay and connect it accordingly ?
     
  4. mcgyvr

    AAC Fanatic!

    Oct 15, 2009
    4,769
    969
    Use the switch to connect or disconnect each charger from the terminals..
    If you use an arduino use a DPDT relay the same as the regular switch..
    DPDT.PNG
     
  5. crutschow

    Expert

    Mar 14, 2008
    13,001
    3,229
    You could likely use just a SPDT relay, and make the grounds for the battery and the two chargers common, unless the two charger commons can't be connected together for some reason.
     
    #12 likes this.
  6. marcf

    Member

    Dec 29, 2014
    136
    19
    I am just curious, but why do you need two chargers? Is the 20amp one going to be just sitting around for 4-5 months?

    Is 'maintaining its gravity' the same thing as giving it an equalization charge?

    Not all battery chargers have the ability to provide this function, does yours?

    http://batteryuniversity.com/learn/article/equalizing_charge
     
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