2.4V NimH battery charger development

Discussion in 'The Projects Forum' started by mishra87, May 19, 2016.

  1. mishra87

    Thread Starter Member

    Jan 17, 2016
    168
    2
    Dear All,

    I want to develop NiMH battery charger for 2.4V (1.2V*2)/1100mAh battery.

    So please suggest me the design criteria under below specifications-

    1. What should be the charging mode NiMH battery i.e. CC or CV or CC-CV .
    2. Could anybody suggest me the schematic and part number to be used.

    Please find the attached detailed specifications -

    Hope to hear you soon !!!

    Mod edit: Converted .doc to PDF. Many members will not open a .doc file due to the threat of viruses.
     
    Last edited by a moderator: May 19, 2016
  2. mishra87

    Thread Starter Member

    Jan 17, 2016
    168
    2
    Comments awaited !!

    Specifications are attached.

    Mod edit: Converted .doc to PDF. Many members will not open a .doc file due to the threat of viruses.
     
    Last edited by a moderator: May 19, 2016
  3. wayneh

    Expert

    Sep 9, 2010
    12,140
    3,054
    Take a look over at Battery University for the best charging strategy for your battery type. Then, find an IC designed to implement that strategy. It's cheaper and more effective than designing your own.
     
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  4. mishra87

    Thread Starter Member

    Jan 17, 2016
    168
    2
    I have gone through battery university but I did not find recommended circuit or device.

    Only explanation about NiMH battery is given.
     
  5. Dodgydave

    Distinguished Member

    Jun 22, 2012
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  6. BobTPH

    Active Member

    Jun 5, 2013
    783
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    If you don't need fast charging, a trickle charger is simple to implement. Use a current source of C/20, in this case 55mA. You can use a 5V source (i.e. USB) and a 47 Ohm resistor. But it will take over 1 full day to charge from empty, or overnight to charge when half full. The good thing about this method is that it is safe to leave the battery in the charger after charging is complete because it is not enough current to damage the battery.

    Bob
     
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  7. mishra87

    Thread Starter Member

    Jan 17, 2016
    168
    2
    Thanks for your reply.
    I do not tricle charging.
    I want to charging to be done by .5C method. .

    For this could you recommend me something.
     
  8. mishra87

    Thread Starter Member

    Jan 17, 2016
    168
    2
    I have divided this into two section
    .
    .
    ..
    1. Universal input to 5V @1A SMPS
    2. NiMH charger chip 2.4@500ma and CC configuration
    3. Led indication for if load is connected and not connected. ..
    4. When battery is fully charged load has to disconnect even if charger is connected

    Please recommend me device as per above
     
  9. Dodgydave

    Distinguished Member

    Jun 22, 2012
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    Are you blind?? Read post #5
    Ltc4060
     
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  10. wayneh

    Expert

    Sep 9, 2010
    12,140
    3,054
    Just to throw in an option, I always throw a LM339 comparator into my chargers. You can use one comparator to detect if anything is connected, another one or two for defined voltages across a shunt, to give an indication of charge current, and maybe the 4th for a warning light or to indicate which mode the charger is in (CV or CC).

    Without reading the details of LTC4060, it probably covers some of these automatically.
     
  11. mishra87

    Thread Starter Member

    Jan 17, 2016
    168
    2
    I have gone through LTC 4060.
    That cost is to high. Usually we can get charger around 3 dollars.

    To drive it from unversal input we need primary switcher and transformer and if we total cost one can not afford.

    So please suggest me low cost solutions. .

    Hope this will help...
     
    Last edited: May 23, 2016
  12. wayneh

    Expert

    Sep 9, 2010
    12,140
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    So finally in post #11 we learn that there is a new specification – dirt cheap – and presumably for making a commercial product. :rolleyes:
     
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  13. mishra87

    Thread Starter Member

    Jan 17, 2016
    168
    2
    I want to make it very clear that...

    There's no point of using such a good word like " dirt cheap or blind "..

    It's a knowledge sharing forum where one can share their experiences..and guides the needy.

    It's not a commercial product.

    We have got our electronic product like Digital pipette controller. This is battery operated instruments. For charging purposes of battery we have been giving readymade ( third party) charger to the customers which are very low cost effective. Now our aim is to develop our own charger and the cost should not be much more higher than our readymade charger. A bit higher will do.

    Let's say we are spending 5$ to buy a charger and if we will spend 10$ in our own developed charger . So there's no point...!!!

    That's why I am looking for low cost effective solutions.

    I am a development engineer and not a management wings who only looks the how much extra cost.

    Hope this help...!!!
     
  14. Dodgydave

    Distinguished Member

    Jun 22, 2012
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  15. wayneh

    Expert

    Sep 9, 2010
    12,140
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    My point was that design choices for a low-cost item to be sold commercially are very different than for the typical hobby project we see here in this forum. Letting people know the context of your question will get bet answers much sooner. I'm not picking on you, it's very common around here that we don't learn the real design parameters until the thread is pages long.
     
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  16. mishra87

    Thread Starter Member

    Jan 17, 2016
    168
    2
    I have selected Viper12 as a primary switcher which is very low cost effective. ..ĺ
    And if we can get NiMH battery charger chip around same prices.

    I want to develop isolated NiMH charger.
     
  17. BobTPH

    Active Member

    Jun 5, 2013
    783
    114
    If you have customers, it is a commercial product!

    Unless you are selling a whole lot of them (10000?) you will not be able to make a charger cheaper than you can get on aliexpress.

    Bob
     
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