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Lead acid battery

Discussion in 'General Electronics Discussion' started by Karthik rajagopal, Apr 26, 2019.

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  1. Audioguru

    Audioguru

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    Sep 24, 2016
    I buy Energizer Ni-MH AAA and AA battery cells. Old ones did not hold a charge longer than 2 months and were guaranteed for only 3 years. New ones are made in Japan maybe by Sanyo/Panasonic using their Eneloop chemistry and come pre-charged, hold a charge for 1 year and are guaranteed for 5 years. Energizer.com has detailed manuals for all of their battery types (they do not make antique lead-acid batteries) available for free on their website.
    Your Ni-MH battery is too old to work properly.

    My Lithium-polymer and Ni-MH rechargeable batteries use Smart Chargers that charge them safely and properly.
     
  2. Karthik rajagopal

    Karthik rajagopal

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    May 9, 2016
    Thanks for the help . I would rather buy a new battery that you mentioned above instead of charging this old one improperly .
     
  3. WHONOES

    WHONOES

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    319
    May 20, 2017
    Find attached a circuit diagram for a 6V lead acid charger. I have kept as simple as I can. Accordingly, the circuit supplied does not reduce the output voltage to a "maintenance voltage". This for the main part is not a problem for as far as I can tell, you don't intend to leave the battery connected to the charger for lengthy periods.

    Note that R6 on the diagram is a battery equivalent for the benefit of simulation.

    I am in the process of writing a circuit description, some build notes and set to work notes.
    If you don't want to tackle the charger say so as this will save time I do not need to spend writing it up.
     

    Attached Files:

  4. Karthik rajagopal

    Karthik rajagopal

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    May 9, 2016
    Thank you so much for this circuit sir. The circuit description will definitely be useful.
     
  5. dave9

    dave9

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    Mar 5, 2017
    I have MANY Eneloops and those relabled to other brands, that have remained at a useful capacity to me for much longer than 5 years.

    I would go this route, but if you need more than about 2000mAh per cell, my 2nd choice would be the Tenergy Centura low self discharge, available at amazon among other places because they are reasonably priced for C and D cell sizes and the D are true D cells not C stuffed in a larger container.

    However with these C and D, many people need a modern smart charger, typically one made for both NiMH and Li-Ion will have a faster charge rate needed to reliably detect the Delta -V charge termination a NiMH smart charger *needs*, and be the type with bays large enough to accommodate C or D, unless you want to rig up some magnet or other charging method like some R/C hobbyists used to do before Li-Ion became the preferred solution.
     
  6. Audioguru

    Audioguru

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    Sep 24, 2016
    Guess what? An old (pre-Eneloop chemistry) Energizer AA Ni-MH cell was 2500mAh. Their NEW Ni-MH C cells and D cells are also rated at 2500mAh. So they and probably many other battery manufacturers make C and D cells with a little AA cell inside??

    A Ternegy Ni-MH D cell weighs much more than an Energizer one and is 10,000mAh.

    Eneloop chemistry was invented by Sanyo who was bought by Panasonic. Tesla electric cars use Ni-MH cells made by Panasonic.
     
  7. dave9

    dave9

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    Mar 5, 2017
    Last edited: May 25, 2019
    hevans1944 and davenn like this.
  8. Audioguru

    Audioguru

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    Sep 24, 2016
    40 or 50 years ago (before Ni-MH) I used Ni-Cad C cells in my sound system for the beach.
     
  9. dave9

    dave9

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    Mar 5, 2017
    I recall that even 40 years ago, GE (General Electric) was putting sub-C NiCd cells in their D casings.
     
  10. hevans1944

    hevans1944 Hop - AC8NS

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    Jun 21, 2012
    If you are buying mainland Asian parts, who knows what is inside the can? I've seen YouTube horror videos, made a few years ago, that reveal the inside of D-size and C-size cans mostly filled with sand or talcum powder, plus something that sort of resembles a dry cell chemistry AA or smaller cell, allegedly re-chargeable.

    Personally, I now purchase only genuine AA-size or AAA-size Eneloop cells and Sony smart chargers because I have been burnt by some really bad MFJ imported Asian Ni-MH cells that I purchased a few years ago on the floor of Hamvention in Dayton, Ohio. MFJ exchanged the defective cells with "no questions asked," but who ordinarily has time to test rechargeable cells during the three or four days that the convention is in town?

    Being a "local" at the time, instead of an out-of-town visitor, I was able to take them home, try them out, and found several that would not accept a charge. So I took them back the next day and exchanged them. Guess what? A few years later some of the exchanged cells won't accept a charge. And some of them leaked corrosive chemicals too, which really pissed me off since a boatload were used inside my Elecraft KX3 portable transceiver. Fortunately I discovered this in time to avoid ruining my radio, but it has forever tarnished my opinion of imported Chinese components, which I now consider suspect until proven different. That doesn't mean I won't purchase imported parts from China on eBay... the low price is sometimes worth the risk... but caveat emptor.
     
  11. davenn

    davenn Moderator

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    Sep 5, 2009

    informative :)

    love his videos
     
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