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Thread: Are these AA's low self discharge?

  1. #1

    Default Are these AA's low self discharge?

    I acquired these recently in some cameras I bought, and I'm debating what to do with them. If they are low self disharge then I would probably keep them. I have enough rechargeable batteries now that some could likely sit for months, and non low self discharge batteries will just discharge too much in that time.

    The Kodaks are precharged so thats the main reason I think they may be low self discharge. The Duracells are precharged also, but the mah rating seems high to be low self discharge and I have read conflicting opinions about the black tops even if they are made in Japan.






  2. #2
    *Flashaholic* StarHalo's Avatar
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    Default Re: Are these AA's low self discharge?

    "Pre-charged" does indeed mean Low Self Discharge LSD; get an inexpensive AA light or two and store them there.

  3. #3

    Default Re: Are these AA's low self discharge?

    After reading your post I threw a set of four that had last been charged on Mar 24/17 in a Maha C-9000 at 1 amp. Here's the numbers, 587 mA, 400 mA
    452 mA and 365 mA.
    These batteries had all tested out between 2410 and 2470 mAh, approximately two years ago and maybe ten cycles. I suspect the one that took 587 mA was the one I had purloined(post Mar 24) from the set for a brief stint in a AA light.

  4. #4

    Default Re: Are these AA's low self discharge?

    Quote Originally Posted by Up All Night View Post
    After reading your post I threw a set of four that had last been charged on Mar 24/17 in a Maha C-9000 at 1 amp. Here's the numbers, 587 mA, 400 mA
    452 mA and 365 mA.
    These batteries had all tested out between 2410 and 2470 mAh, approximately two years ago and maybe ten cycles. I suspect the one that took 587 mA was the one I had purloined(post Mar 24) from the set for a brief stint in a AA light.
    Where these the same Duracell or Kodaks that I have in my pictures, or some other precharged batteries?

    So your saying that after fully charging, and then sitting for about 6 months, they only have an average of about 450 mAH left or only about 18% of their initial capacity?

    Its been a little while since i brushed up on my battery terminology, but I assume your mA numbers are actually suppose to be mAH ?
    Last edited by konsole; 09-10-2017 at 11:32 AM.

  5. #5

    Default Re: Are these AA's low self discharge?

    StarHalo mentioned this and some reading seems to verify what he said. Correct me if I'm wrong about this.

    From what I have read it seems that "precharged" is generally a code word for low self discharge batteries? Is that a fair assumption? Obviously precharged just means its been charged by the factory, but if a regular nimh battery was precharged by the factory, then if its bought a year later the charge probably would have dropped to nothing. In that case it wouldnt make sense to label it precharged if theres a good change it will no longer have a charge by the time its bought. I guess a non low self discharge battery could be charged by the factory and then labeled precharged, but consumers would probably point out how these batteries were frequently being bought with no or very little charge and beign misled by the labeling.

    Age of the battery and quality of manufacture aside. Is it generally assumed that "precharged" batteries have a much lower self discharge rate then batteries that arent labeled "precharged" or "low self discharge"?

  6. #6
    *Flashaholic* StarHalo's Avatar
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    Default Re: Are these AA's low self discharge?

    Quote Originally Posted by konsole View Post
    From what I have read it seems that "precharged" is generally a code word for low self discharge batteries?
    Correct.

    Quote Originally Posted by konsole View Post
    Age of the battery and quality of manufacture aside. Is it generally assumed that "precharged" batteries have a much lower self discharge rate then batteries that arent labeled "precharged" or "low self discharge"?
    Also correct. The difference is so vast that it's probably not worth keeping your old/non-LSD NiMHs as the amount of care and maintenance they require makes them more trouble than help.

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    Default Re: Are these AA's low self discharge?

    I'll second StarHalo, but would like to also add that there is one single use case for preferring old-type NiMHs, and that is in devices that will constantly charge. Old-style can supposedly tackle a higher rate over constant trickle overcharge. Personally I'd be tempted to replace those devices as well though.

  8. #8

    Default Re: Are these AA's low self discharge?

    I should have been more specific, trying to post last night almost transitioned into an exercise in noose tying.
    Allow me to clarify. They were the same Duracell batteries as pictured. I charged them at 1 amp, the mAh(yes I cheated) numbers I provided were what the batteries took in charge to fill, not capacity after discharge.
    So, after six months of sitting idle they had approximately 2000 mAh of capacity left, based on my initial capacity results that had them all north of 2400 mAh.
    I have several of these batteries as well as the Duracell white top 2000 mAh "Duraloops" and all have performed well.
    . . . . and yes, precharged = LSD. Certainly in my experience.

  9. #9

    Default Re: Are these AA's low self discharge?

    Up All Night,

    oh ok so you have the same Duracells that are in my pictures, and when you charged them and then let them sit for 6 months they still have about 80% of their capacity left?

  10. #10

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    Default Re: Are these AA's low self discharge?

    Quote Originally Posted by Up All Night View Post
    I charged them at 1 amp, the mAh(yes I cheated) numbers I provided were what the batteries took in charge to fill, not capacity after discharge.
    Using what they take in isn't a very good measure of battery quality/health. You're essentially measuring the energy that you used to both heat and charge the battery. As a battery grows older, it'll heat more and charge less, but you'd still be measuring the total energy spent for both.

    Also, you can't compare the charge it took with the rates capacity of the cell. There will be a loss, during both charging and discharging, and you won't get back everything you put in as useful electricity.

  11. #11

    Default Re: Are these AA's low self discharge?

    Quote Originally Posted by terjee View Post
    Using what they take in isn't a very good measure of battery quality/health. You're essentially measuring the energy that you used to both heat and charge the battery. As a battery grows older, it'll heat more and charge less, but you'd still be measuring the total energy spent for both.

    Also, you can't compare the charge it took with the rates capacity of the cell. There will be a loss, during both charging and discharging, and you won't get back everything you put in as useful electricity.
    All valid points. After being all agog with charge, discharge, analyze, refresh etc. I've basically boiled it down to unless I notice a performance decline or see some other anomaly I don't chase details. The numbers I quoted were to give an idea​ of self discharge characteristics for this particular model of cell, nothing more.

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