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Thread: What's the Best Battery Charger?

  1. #31
    Banned Kevin Rooney's Avatar
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    Quote Originally Posted by DougPaul View Post
    You probably already have some--they are standard in laptops, cellphones, and many cameras...

    Doug
    Of course. But not AA or AAA's, which is mostly what this thread is about.

  2. #32
    Senior Member DougPaul's Avatar
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    Quote Originally Posted by Kevin Rooney View Post
    Of course. But not AA or AAA's, which is mostly what this thread is about.
    NiMHs are a lot cheaper, easier, and safer for general purpose use...

    Doug

  3. #33
    Senior Member sardog1's Avatar
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    Warning about Energizer Duo USB charger

    No, it won't burn your house down or supercharge your battery. It just turns over control of your computer to unknown hands. From the manufacturer's notice to users:

    "ST. LOUIS, March 5, 2010 /PRNewswire via COMTEX/ -- Energizer has been informed by the CERT Coordination Center (CERT) that the Windows software that was referenced and made available via a download with its Duo Charger, Model CHUSB, contains a vulnerability. Energizer introduced the Duo Charger in the United States and the USB Charger in Latin America, Europe and Asia in 2007. Both products charge Nickel Metal Hydride batteries from both a wall outlet and a USB connection. The product included a feature that would allow the user to view the battery charging status on a computer if associated software was installed. The Duo Charger product documentation referenced www.energizer.com/usbcharger to download the software. The site offered downloadable software in both Windows and Apple(R) versions; however only the Windows version contained the vulnerability.
    Energizer has discontinued sale of this product and has removed the site to download the software. In addition, the company is directing consumers that downloaded the Windows version of the software to uninstall or otherwise remove the software from your computer. This will eliminate the vulnerability. In addition CERT and Energizer recommend that users remove a file that may remain after the software has been removed. The file name is Arucer.dll, which can be found in the Window system32 directory."
    sardog1

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  4. #34
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    So now there is no chance that my Energizer Duo Charger is going to become self-aware, right?

  5. #35
    Senior Member sardog1's Avatar
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    Quote Originally Posted by Remix View Post
    So now there is no chance that my Energizer Duo Charger is going to become self-aware, right?
    Nah, we took the prototype and put it in a secure vault at Cyberdyne Systems Corporation. No worries.
    Last edited by sardog1; 03-08-2010 at 07:37 PM.
    sardog1

    "Å! kjære Bymann gakk ei stjur og stiv,
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    kom kjenn, hot d'er, som heiter Svevn og Mat,
    og Drykk og Tørste og det heile, som
    er Liv og Helse i ein Hovedsum."

    -- Aasmund O. Vinje, "Til Fjells!"

  6. #36
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  7. #37
    Banned Kevin Rooney's Avatar
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    My new toy arrived today, along with a pack of Eneloop batteries - thank you Amazon. Am running a discharge/refresh cycle on 4 at the moment.

    One interesting note - this "smart charger" cannot recharge a battery if it's totally flat, so I guess I'll keep the old charger around just in case.

  8. #38
    Senior Member DougPaul's Avatar
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    Quote Originally Posted by Kevin Rooney View Post
    One interesting note - this "smart charger" cannot recharge a battery if it's totally flat, so I guess I'll keep the old charger around just in case.
    Most smart chargers perform some tests on the cell to determine the type and health before starting the charge. Totally flat or weak (worn down or damaged) cells can fail and the charger will refuse to charge them. Different chargers can have different thresholds, so if you have several chargers, one may accept the flat/weak cell.

    I have a simple (dumb, non-smart, no automatic shutoff) trickle charger (MH-C126S) which applies a 60 mA charge current. If all else fails, I can use this to put an initial charge in a flat/weak cell and finish the charge with a smart charger.

    Note: a trickle charge of greater than about .05C for NiMH and .1C for NiCad can damage the cells. (60 mA is .03C for a 2000 mAh cell.) C=the cell capacity in amp-hours.

    Doug

  9. #39
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    One interesting note - this "smart charger" cannot recharge a battery if it's totally flat, so I guess I'll keep the old charger around just in case.
    My Maha chargers will start charging a totally flat battery within 30 minutes. I have put a dead cell in and nothing happened immediately. After some time, the charge light came on.

    When the maha charger has a problem with a cell-- unable to charge or inserted into the charger backwards-- the red charging light flashes.

    Kevin- I suggest you get a totally dead cell and convince yourself that charging will start after enough charge has entered the battery so that the charger can see "something".
    Last edited by Remix; 03-09-2010 at 02:58 AM. Reason: grammar

  10. #40
    Senior Member sardog1's Avatar
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    You guys are doing a real service here for us and for the planet generally with your tips. Thanks.
    sardog1

    "Å! kjære Bymann gakk ei stjur og stiv,
    men kom her up og kjenn eit annat Liv!
    kom hit, kom hit, og ver ei daud og lat!
    kom kjenn, hot d'er, som heiter Svevn og Mat,
    og Drykk og Tørste og det heile, som
    er Liv og Helse i ein Hovedsum."

    -- Aasmund O. Vinje, "Til Fjells!"

  11. #41
    Banned Kevin Rooney's Avatar
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    Quote Originally Posted by Remix View Post
    Kevin- I suggest you get a totally dead cell and convince yourself that charging will start after enough charge has entered the battery so that the charger can see "something".
    Thanks - I have a couple of batteries in my stash of AA's and AAA's which I suspected were toast, perhaps damaged by the "dumb" charger I'd been using. The cases appear to have swelled, causing the wrap to separate slightly. When I put one of them in the charger, it repeatedly displayed "Null", so that tells me battery is of dubious value anyway. Helps me justify the purchase of the Sanyo Eneloops

  12. #42
    Senior Member DougPaul's Avatar
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    Quote Originally Posted by Remix View Post
    My Maha chargers will start charging a totally flat battery within 30 minutes. I have put a dead cell in and nothing happened immediately. After some time, the charge light came on.
    I haven't observed this--occasionally I have looked at the charger after several hours and seen the red light still flashing... But it may depend on the cell and specific charger. I'll watch for it (but I rarely try to charge a really dead/flat cell*). The trickle charger always managed to put some charge in some really worn/damaged cells when the smart chargers refused to do anything with them.

    Quote Originally Posted by Kevin Rooney View Post
    Thanks - I have a couple of batteries in my stash of AA's and AAA's which I suspected were toast, perhaps damaged by the "dumb" charger I'd been using. The cases appear to have swelled, causing the wrap to separate slightly. When I put one of them in the charger, it repeatedly displayed "Null", so that tells me battery is of dubious value anyway. Helps me justify the purchase of the Sanyo Eneloops
    If they have swollen or leaked, discard them. The electrolyte is pretty corrosive and may damage whatever you put them in.

    Someday the Eneloops will be old and tired too... (NiMHs are typically rated for ~500 (full) cycles.) And you will probably replace them with no regard for their feelings...


    * Running a cell down to zero V (totally flat) or reversing it while trying to get the last bit out of a group of cells can damage it. It is much better for the cell to stop when its voltage drops down to 1 V. You have used almost all of the energy in the cell by this point anyway. (My GPS, for instance, uses 2 AA cells and shuts down at 2V, thus protecting the cells from damage. LED lights should also generally be safe for NiMHs, but incandescent lights would not be safe.)

    Doug

  13. #43
    Senior Member LivesToHike's Avatar
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    Thanks

    I've also had alot of trouble with a quick charger, and even my "supposed" slow charger also cooking my NiMd batteries; I use the same Energizer AA batteries mentioned by folks. My batteries now rarely hold a charge for more than a few days - I've been caught by this during summer hikes - my camera's lense deployed and then went into a very deep, deep sleep.

    I'm going to put one of the Maha slow chargers mentioned on my wish list for the end of the month or early next month.

    Thanks everyone for sharing your experiences and recommendations.

    Best,
    --Mike
    --- Help stamp out entropy!

  14. #44
    Senior Member DougPaul's Avatar
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    Quote Originally Posted by LivesToHike View Post
    I've also had alot of trouble with a quick charger, and even my "supposed" slow charger also cooking my NiMd batteries; I use the same Energizer AA batteries mentioned by folks. My batteries now rarely hold a charge for more than a few days - I've been caught by this during summer hikes - my camera's lense deployed and then went into a very deep, deep sleep.

    I'm going to put one of the Maha slow chargers mentioned on my wish list for the end of the month or early next month.
    Two to four hour smart chargers are generally safe for NiMH cells. (See, for instance, my recommendations earlier in the thread.) If the cells become too hot to touch for any length of time, they are too hot and are likely to become damaged. (Overheating while charging is a common way of damaging the cells.) One of my chargers has a temp sensor and sometimes suspends charging during a 2-hr charge to let the cells cool down. (The sensor is external to the cell and may be set conservatively. Another charger with a similar charge rate has never shown any cell damage.) I use a fan to put a gentle cooling breeze on the cells and it fixes the problem. In general, putting a fan on the charger and cells isn't a bad idea..

    Some chargers are notorious for overheating the cells: eg the Ray-o-Vac PS-4 which had a 1 hr charge rate (with the switch set to NiMH). If you set the switch to NiCad, it had a 2 hr charge rate which was safe for NiNH cells.


    Once overcooked, the cells are permanently damaged--the only thing you can do is replace the cells and the charger.

    Doug

  15. #45
    Senior Member LivesToHike's Avatar
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    Hmmm, point taken.

    Quote Originally Posted by DougPaul View Post
    Two to four hour smart chargers are generally safe for NiMH cells. (See, for instance, my recommendations earlier in the thread.) If the cells become too hot to touch for any length of time, they are too hot and are likely to become damaged. (Overheating while charging is a common way of damaging the cells.) One of my chargers has a temp sensor and sometimes suspends charging during a 2-hr charge to let the cells cool down. (The sensor is external to the cell and may be set conservatively. Another charger with a similar charge rate has never shown any cell damage.) I use a fan to put a gentle cooling breeze on the cells and it fixes the problem. In general, putting a fan on the charger and cells isn't a bad idea..

    Some chargers are notorious for overheating the cells: eg the Ray-o-Vac PS-4 which had a 1 hr charge rate (with the switch set to NiMH). If you set the switch to NiCad, it had a 2 hr charge rate which was safe for NiNH cells.


    Once overcooked, the cells are permanently damaged--the only thing you can do is replace the cells and the charger.

    Doug
    Thanks, Doug. I have a Ray-Vac charger and a Durcell chargers, but I'll have to verify the model #'s. I think the former takes more than a 60 minutes (4+ hours), and the latter takes anywhere from 15 to 60minutes to charge 4 AA NiMd's.

    Regardless, both these chargers appeared to have overheated cells. The cells are still very warm when the charger has finished, giving me the impression that the charger hasn't really shutdown charging, or that the trickle charge really isn't a trickle. I've never measured the current draw, but that would be easy to do if I wanted to know.

    I'll just replace all my AA cells and the charger as you suggested.

    --Mike
    --- Help stamp out entropy!

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