Powering LED's and Charging Batteries

Discussion in 'The Projects Forum' started by luis84, Jun 9, 2011.

  1. luis84

    Thread Starter New Member

    Jun 8, 2011
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    0
    Hello Everyone,

    I have a bank of 4 batteries connected in a series. They are rechargeable. They power a bar of 60 White LED's.

    They were setup before to work with no transformer! Yikes! So that design has been removed. I know have the batteries and the 60 LED array. I want to try and setup a system where I can charge the batteries / and use them to power the LED's.

    How would I go about this the easiest way? I don't know the power consumption of the LED's, but I estimate about 20W for the entire bar?

    The batteries also have no rating. They came charged and power the LED bar fine. All together they last about 16 hours of usage. However, they are not marked nor rated invidiaully.

    I just know that they are sealed led-acid batteries and they slow charge. No further details on them. Any way I can safetly have them charge without risk.

    Any suggestions on how to wire these LED's / batteries to a transformer SAFETLY?

    Thank you...

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  2. SgtWookie

    Expert

    Jul 17, 2007
    22,182
    1,728
    You're not giving us a whole lot to go on.

    4 12v lead-acid batteries in series will vary from 48v (basically discharged) to ~54.8v when on "float" charge (4 x 13.7v).

    It's really not a good idea to charge them in series, as if one battery fails with a shorted cell, the remaining batteries will be overcharged. Also, as batteries age, their capacities can vary significantly - which will cause the voltage drop across each battery to vary.

    Without data on the batteries, it will be difficult to know at what rate you need to charge them.

    You will need to do research on the batteries, and find other batteries that are the same physical dimensions as the batteries you now have. Once you do that, then post the manufacturer and model number of the batteries, most preferably with an AH rating.
    If you supply the MFG and model, we can likely track down a datasheet for them.
     
  3. luis84

    Thread Starter New Member

    Jun 8, 2011
    5
    0
    Okay great! These batteries are new but I do not have any info really. They are just rectangular, black batteries with a 0 on the bottom. 0 Other information. They came from China and were used by a company called Casibao.
     
  4. #12

    Expert

    Nov 30, 2010
    16,355
    6,852
    Do you have a meter to measure their voltage? Do you have a meter to measure current?
     
  5. Kermit2

    AAC Fanatic!

    Feb 5, 2010
    3,795
    951
    I'm curious why you think a transformer is required with a DC battery circuit and LED's, and why it seems important to you that it have one?
     
  6. SgtWookie

    Expert

    Jul 17, 2007
    22,182
    1,728
    It seems that our OP rightfully did not approve of the non-transformer supply/charger that the lights originally came with, and wants to build a safe supply/charger that is isolated from the mains using transformer coupling.

    Now the immediate questions are, what's the AH capacity of the batteries so the proper charge rate can be determined, and how much current does the LED array require when it's on? Hopefully, the charge rate will be high enough so that the batteries can be charged slowly if the light is on, but not be overcharging when the light is off.
     
  7. luis84

    Thread Starter New Member

    Jun 8, 2011
    5
    0
    The LED Panel (even if purchased seperately) does not say what it requires.

    It's a 60 LED panel, I assume them to be about 0.3 watts each since I work with LED's alot and ones similar to this have the same requirement.
     
    Last edited: Jun 9, 2011
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