high current battery charger

Discussion in 'General Electronics Chat' started by new_bro, Feb 1, 2009.

  1. new_bro

    Thread Starter New Member

    Jan 30, 2009
    6
    0
    hi friends

    i have a 100 Amp Lead acid battery.i want to a build quick battery a charger
    which should be able to charge my battery within 6 hours i have been using one battery charger which uses 20 amp rectified supply only, diodes heats very quickly .i want to build a charger using same 20 amp transformer so friends if there is any solutions.




    New_bro
     
  2. SgtWookie

    Expert

    Jul 17, 2007
    22,182
    1,728
    You really don't want to charge a lead-acid battery that quickly, as you will shorten it's life dramatically due to the temperature increase.

    Instead, get several batteries, and charge them at a 5A rate. It will take four times as long to charge them up, but your batteries will last three times as long.
     
  3. new_bro

    Thread Starter New Member

    Jan 30, 2009
    6
    0
    friend
    thank u for ur quick suggestion.in my country we have long power outage .we only have 8hrs supply per day we will not have power for next 16 hours.i really want to build a charger which charges my battery quick ,but i will charge it slowly as u said after each 5 cycles i just want my charger which will be able to limit charging current 5 amp at least and 15 amp at most and also afraid of being battery overcharged n deep discharge.



    new_bro


    -



     
  4. jpanhalt

    AAC Fanatic!

    Jan 18, 2008
    5,699
    907
    Larger diodes or heat sinking them will help control the temperature. However, you can't change the chemistry of lead-acid batteries because you only have 8 hours of power.

    Other battery types have much better fast-charge characteristics, such as NiMH and NiCd, but they are also more expensive.

    One question to consider is how much power do you need for the 16hours without utility power?

    John
     
  5. Wendy

    Moderator

    Mar 24, 2008
    20,766
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    Actually guys, fork lift batteies do this routinely, and they are nothing but lead acid, giant size. I used to get to service those suckers. Hated it, even with full protective gear I had more than one brand new jeans come up swiss cheese.
     
  6. studiot

    AAC Fanatic!

    Nov 9, 2007
    5,005
    513
    Don't you mean 100 amp-hours?

    This is about right for a medium to large sized car.

    A 100 amp battery is meaningless. A typical starter will draw several times this during starting.

    Most UK garages have 100 to 200 amp 'fast' chargers, but would not employ them frequently on an individual standard car battery.

    Most home chargers will readily achieve 5 amps anyway.

    Most car alternators charge at at least 20 amps when the engine is running.

    The nominal rated charge current for batteries is known as the 0.1C rate that is the amphour rating divided by ten, so you should be able to do up to 10 amps without worry.

    If you want the best of both worlds get two chargers, a 20 amp plus job and a lower trickle charger. Are you fully discharging the battery between 8 hour on periods? I remember doing this during the infamous 'three day week' we had back along during a strike.
     
  7. Wendy

    Moderator

    Mar 24, 2008
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    2,536
    That sounds about right, fork lift batteries were charging in exess of 120A (some cases almost 200A), then went to trickle charge mode to keep them topped off. One of the weekly PMs on these suckers is to replace the water.
     
  8. new_bro

    Thread Starter New Member

    Jan 30, 2009
    6
    0
    Dear friends thanks all of you ,finally i have build charger which is 10amp.my battery doesn,t get fully charged .i reduced my my consumption and adjusted myself according to load shedding



    new bro
     
  9. thatoneguy

    AAC Fanatic!

    Feb 19, 2009
    6,357
    718
    Make sure you don't use "Sealed Batteries", so that you can check and top off the water with distilled water, although it may be difficult for you to buy there, it can be "made" if you have a stove/small fire and 2 pots. That might give extra life to the batteries, or shorten their lives if adding water containing minerals.

    The Acid doesn't go away, only the water, so to speak, so pop the caps off and check water levels/top off before charging, put them back on when done charging, ready to use. KEEP AWAY FROM FLAME WHILE CHARGING! Sealed Battery or not! They release explosive fumes, such as hydrogen.
     
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