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  1. #1
    Join Date
    Apr 2005
    Posts
    9

    AA batteries self-discharge in just hours?!

    Hi all,
    Thanks for reading!

    I've been the happy owner of a Canon A510. One thing really disturbs me: my AA NiMH batteries seem to lose their functionality after just a few months and perhaps 10-20 charges (rough guess). After I bought new batteries ... the very same thing happened again! What happens is that after purchase, batteries work fine for some time (hold their charge, give many shots), until one day the camera reports them empty after they were fully charged but left unused for a few hours. I could probably take a hundred shots right after charging but leaving the batteries alone for more than an hour seems to discharge them - in other words my camera is not there when I need it. Funny detail: when put in a recharger with an LCD, the LCD shows them still half-full and charges them to full in a fraction of the normal charge time. Also, these 'empty' batteries can still drive my remote control for a year. What is wrong with my batteries, with my camera, with me??

    Any help would be greatly appreciated!

  2. #2
    Join Date
    Apr 2005
    Posts
    9
    Potentially relevant detail: both battery sets I bought and intensively used during a holiday, then left the camera barely used for the following months, after which the problem occured.

  3. #3
    Join Date
    Mar 2007
    Posts
    2,132
    More details. What kind of AA's are these for one...are these cheap knock off types or what?

    Two, buy Eneloops and you won't have that problem again. Hold their charge for 6+ months and can be recharged 1,000 times each.
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  4. #4
    Join Date
    Apr 2005
    Posts
    9
    Good point: they're cheap knock-offs indeed. The first set came bundled with my camera off Ebay (Bilora, apparently some German brand, 2300mAh, 1.2V). The second set were no-name batteries that came bundled with a $25 recharger I bought at Wal-Mart (2500mAh, 1.25V).

  5. #5
    Join Date
    Jul 2005
    Posts
    8,163
    NiMH batteries self-discharge. It's a side-effect of their chemistry. Enter Sanyo Eneloop, Rayovac Hybrid, Duracell Pre-Charged, et al. They self-discharge but at a MUCH lower rate, at the expense of capacity (number of shots per charge). Standard NiMH are better for the power user (someone who will use the batteries HARD in a short period of time), while low-discharge like the previously named are better for the casual user (someone who will let the device sit idle for long periods of time).
    Last edited by cdifoto; 02-02-2009 at 06:48 AM.
    Ouch.

  6. #6
    Join Date
    Jul 2004
    Posts
    4,173
    The charger might be the weak link. Ultra fast charges will cook a battery. What kind of charger do you have and how fast does it charge a set of batteries?

  7. #7
    Join Date
    Apr 2005
    Posts
    9
    About the charger: for the first pair of batteries I used a basic GP charger (takes 24h to charge, no fancy trickling feature though). For the second pair I used an ultra-fast 1h Wal-Mart charger (no known brand).

    Thanks for the help, everyone! The first commenter's suggestion about the batteries prompted me to do some googling - and what I found goes in the same direction as your other comments: I need quality batteries and a decent charger. So I'm going to get better batteries (one of the brands mentioned) and use my slow GP charger.

    I'm glad I can continue to use my camera because I honestly don't think it can be beaten in terms of image quality (among p&s). Despite its 3MP...

  8. #8
    Join Date
    Aug 2005
    Posts
    6,931
    Three words,

    Eneloops
    Eneloops
    Eneloops

    On top of that buy a decent charger something like a Powerex (link here) and you will never look back.

  9. #9
    Join Date
    Dec 2008
    Location
    Richmond, VA
    Posts
    9
    Quote Originally Posted by liekloo View Post
    About the charger: for the first pair of batteries I used a basic GP charger (takes 24h to charge, no fancy trickling feature though). For the second pair I used an ultra-fast 1h Wal-Mart charger (no known brand).

    Thanks for the help, everyone! The first commenter's suggestion about the batteries prompted me to do some googling - and what I found goes in the same direction as your other comments: I need quality batteries and a decent charger. So I'm going to get better batteries (one of the brands mentioned) and use my slow GP charger.

    I'm glad I can continue to use my camera because I honestly don't think it can be beaten in terms of image quality (among p&s). Despite its 3MP...
    Pretty much everything that needs to be said has already been said here by one person or another, but you still don't have a good picture of what you need to do.

    Check out Battery University and/or visit Candle Power Forums and their battery section.

    There are two primary issues - crappy cells and crappy chargers. If you use a crappy charger with good cells, you'll eventually get crappy cells which is what you're about to do. I don't know precisely what charger you have (the 24 hour one), but it's a pretty good bet that it's a dumb charger and it's likely that it's the one that ruined your cells.

    If your cells are only depleted 25% (75% left) and you charge them in that charger, it will overcharge them by 75% because it's not a smart charger. It doesn't know when they are charged - it only times the charge. Slow charging is not necessarily safe. The recommended charging rate is actually between one half (.5C) and the full capacity (1C) of the cell. An Eneloop is 2000mA, so the charging rate should be between 1000mA and 2000mA which equates to a 1-2 hour charge time for a depleted cell.

    The 'fast charger' that someone referred to that cooks cells are the 10-15 minute chargers and that still isn't really a true statement. Those fast chargers do a good job with 'healthy' or good cells. They will shorten the life of your cells by a small amount, but the trade off may be worth it for serious users. Their bad rap of cooking cells is primarily because of using crappy cells in them.

    I don't know which charger your 1 hour charger is, but it is likely a smart charger and therefore much better than your timed charger. You can find ratings of several chargers (Charger Shootout) on Candle Power Forums. Some chargers can overheat cells, which ruins them, or overcharge them, which ruins them, or undercharge them, which doesn't give you full use of your cells, etc.

    Currently, (IMO) the best of the chargers/analyzers on the market for AA cells is the Maha Powerx WizardOne (MH-C9000) that someone referenced above. It's a bit pricey, but worth it to get the most from your investment in cells. If all you use rechargeables for are 2-4 cells for a camera, then it's probably not worth it. In that case, just get 2-3 sets of cells and a decent smart charger ($20-30) and replace the cells when they start to drop in performance.

    The use of rechargeables is not just buy and use. You really need to do some research to understand them and how to use them, although Eneloops have done much to simply and idiot proof them for the masses. A good example would be someone who spends $1200 on a decent DSLR and only uses it as a point and shoot.

  10. #10
    Join Date
    Aug 2005
    Posts
    6,931
    Quote Originally Posted by ksva View Post
    A good example would be someone who spends $1200 on a decent DSLR and only uses it as a point and shoot.
    Or as happens here often spends $1200 on a DSLR then posts asking whether some dodgy memory cards on ebay are worth buying because they are $3 cheaper than the real thing in the stores.

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