Charging rate and battery life

Discussion in 'Digital Photography' started by MikeM, Mar 9, 2007.

  1. MikeM

    MikeM Guest

    I just bought some Duracel rechargable 2650 MAh NiMH batteries and a
    Duracell charger. The 2 Duracel chargers were 30min mn and 1 hr. Does
    this high speed charging shorten the life of batteries?

    Thanks
    Mike
     
    MikeM, Mar 9, 2007
    #1
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  2. MikeM

    Mark² Guest

    MikeM wrote:
    > I just bought some Duracel rechargable 2650 MAh NiMH batteries and a
    > Duracell charger. The 2 Duracel chargers were 30min mn and 1 hr. Does
    > this high speed charging shorten the life of batteries?


    Yes.
    --
    Images (Plus Snaps & Grabs) by Mark² at:
    www.pbase.com/markuson
     
    Mark², Mar 9, 2007
    #2
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  3. MikeM

    Bob Williams Guest

    MikeM wrote:
    > I just bought some Duracel rechargable 2650 MAh NiMH batteries and a
    > Duracell charger. The 2 Duracel chargers were 30min mn and 1 hr. Does
    > this high speed charging shorten the life of batteries?
    >
    > Thanks
    > Mike


    Certain batteries are designed to tolerate very high charging rates and
    get very hot. Others require slower charging rates. It is a "battery
    specific" thing. Often, it is the high capacity batteries that can take
    the faster charging rates. (2650 MAh is high).
    Follow the recommendations of the manufacturer for your specific
    Bob Williams
     
    Bob Williams, Mar 9, 2007
    #3
  4. MikeM <> wrote:
    : I just bought some Duracel rechargable 2650 MAh NiMH batteries and a
    : Duracell charger. The 2 Duracel chargers were 30min mn and 1 hr. Does
    : this high speed charging shorten the life of batteries?

    I do not know about your particular charger, but some chargers have multi
    rates by having the longer time charge include a full discharge before
    charge. If this is the case you could probably get away with only using
    the long charge every 5 or 6th charge or when your batteries have gone
    unused for a month or more. On the other hand some chargers make a faster
    charge rate setting by doubling (or whatever) the current being presented
    to the battery. This can cause heating (or even overheating) the battery
    which will likely cause the chemicals inside the battery to become
    damaged. This may weaken the chems and reduce the lifespan of the battery
    (and in worse case could even increase the chances of battery leakage or
    even explosion).

    So depending on what the charger is actually doing, the short recharge
    could be the norm with occasional refreshes with the long charge, or the
    long charge could be the safe way, with the short charge being only in
    emergencies. Maybe if the manual does not spell out what is happening, and
    there is no clue on the charger makers plate (for example, two listed
    output current listings would hint at the doubling current method), then I
    would see if you can get info from the manufacturer. Until you get more
    info the safe way would be to stick with the long charge (IMHO) while you
    gather more info. In either case the long charge is less likely to cause
    damage even if it does take longer. Besides if you get multiple sets of
    batteries and chargers, you should be able to use a single set of
    batteries for more than the hour it takes to charge the new set. One set
    in the camera being used for an hour, and one in the charger charging to
    be used when the set in the camera runs out.

    Randy

    ==========
    Randy Berbaum
    Champaign, IL
     
    Randy Berbaum, Mar 9, 2007
    #4
  5. MikeM

    ASAAR Guest

    On Fri, 09 Mar 2007 03:35:03 GMT, MikeM wrote:

    > I just bought some Duracel rechargable 2650 MAh NiMH batteries
    > and a Duracell charger. The 2 Duracel chargers were 30min mn and
    > 1 hr. Does this high speed charging shorten the life of batteries?


    Very slightly, not enough to worry about. NiMH batteries should
    last for an extremely large number of charge cycles with either
    charger, if pampered. Most people either don't know how to do this,
    or for all practical purposes are unable to, since they won't give
    the batteries enough use. What little damage is done occurs when
    the NiMH cells overheat in the charger. During most of the charging
    time the cells remain at worst, slightly warm, only getting hot
    during the last couple of minutes as they become fully charged. I
    don't know that this short, hot period causes an appreciably
    different amount of damage with either charger. Just plucking
    numbers out of thin air (theorizing), the 1 hour charger might
    generate most of its damaging heat during the last two minutes of
    charging, but the 30 minute charge, while producing more heat, may
    only do so for a shorter, final one minute of charging, which would
    tend to equalize the life-shortening aspect of normal charging. I
    highly doubt that anyone here really knows which charger reduces
    battery life more than the other. Most of what is known about
    damaging batteries due to heat probably was learned not from "smart"
    chargers that sense when to stop charging, but from "dumb" chargers
    that aren't designed to stop charging once the batteries become
    fully charged. They therefore reach the point where damaging heat
    occurs, and carry on, regardless. What's really happening is only
    truly known by manufacturer's battery design engineers, and I
    haven't seen this aspect discussed in any of their battery
    application manuals or data sheets. If you want to ensure long
    battery life, don't ever leave them in devices so long that one or
    two of the cells show practically zero voltage when removed. This
    isn't a rare happening, and when it does occur, most users are
    completely unaware, only eventually noticing (if at all) that their
    batteries aren't lasting as long in their cameras as they once did.
     
    ASAAR, Mar 9, 2007
    #5
  6. MikeM wrote:
    > I just bought some Duracel rechargable 2650 MAh NiMH batteries and a
    > Duracell charger. The 2 Duracel chargers were 30min mn and 1 hr. Does
    > this high speed charging shorten the life of batteries?
    >
    > Thanks
    > Mike


    Charging batteries is a rather complex science and art.

    I would suggest that other than using a charger that is not designed for
    the type of battery you are using the next worse thing is using a charger
    that charges each cell the same rather than charging each cell as it needs.
    Most chargers charge all the cells as a group. Some, the good ones, make
    adjustments to the charge going to each cell. That means on cell may get 5
    or 50% for charge time than the one next to it. Just because they were all
    used in the same piece of equipment at the same time does not mean they need
    the same charging. Over charging or undercharging can reduce battery
    performance and life.


    --
    Joseph Meehan

    Dia 's Muire duit
     
    Joseph Meehan, Mar 9, 2007
    #6
  7. MikeM

    Jim Townsend Guest

    MikeM wrote:

    > I just bought some Duracel rechargable 2650 MAh NiMH batteries and a
    > Duracell charger. The 2 Duracel chargers were 30min mn and 1 hr. Does
    > this high speed charging shorten the life of batteries?


    Fast 1/2 hr charging does reduce battery life, but not drastically.
    The extra heat generated by the high current charge dries out the
    electrolyte faster and is a bit harder on the internal components.

    If the cost of a single battery were $40.00, I would use a
    conventional charger. But the cost is more like $4.00 a battery, so
    the convenience of not waiting hours on end for batteries to charge
    is worth it.
     
    Jim Townsend, Mar 9, 2007
    #7
  8. MikeM

    MikeM Guest

    The Duracell chargers to pick from where I bought the Duracell
    batteries were 1/2, 1, or 15 hr. As the batteries were for travel I
    got the 1 hr charger. I tried charging Varta 15-minute 2000 mAh
    batteries and Duracell 2650 mAh batteries. The Varta battries got warm
    but the Duracell batteries got hot. I suppose the 15-minute batteries
    stayed cooler because they are designed for faster charging. Maybe I
    should have got the 15-hr charger.

    Mike


    On Fri, 09 Mar 2007 03:35:03 GMT, MikeM <>
    wrote:

    >I just bought some Duracel rechargable 2650 MAh NiMH batteries and a
    >Duracell charger. The 2 Duracel chargers were 30min mn and 1 hr. Does
    >this high speed charging shorten the life of batteries?
    >
    >Thanks
    >Mike
     
    MikeM, Mar 9, 2007
    #8
  9. MikeM

    Guest

    I picked up a very similar charger, if not the same, then other
    night. It came with four 2200-ish mAh batteries and a charges them
    in 15 minutes on AC [ the car lighter definitely took more time :
    ( ]. However, the charger was built with a fan to blow air from
    underneath the charger to blow air across the batteries as they were
    charging - not a bad (partial) solution. I haven't tried my really
    old batch of sub-2000 mAh NiMhs... maybe an excuse to try them, fry
    them, and get the 2650 mAh ones :)
     
    , Mar 9, 2007
    #9
  10. MikeM

    Ron Hunter Guest

    MikeM wrote:
    > I just bought some Duracel rechargable 2650 MAh NiMH batteries and a
    > Duracell charger. The 2 Duracel chargers were 30min mn and 1 hr. Does
    > this high speed charging shorten the life of batteries?
    >
    > Thanks
    > Mike


    It might, but if the battery was made for fast charging, it is not
    likely to damage it noticeably. Given the small cost of NIMH batteries,
    is it really significant if fast charging reduces the life from 1000
    charges to only 500?
     
    Ron Hunter, Mar 9, 2007
    #10
  11. MikeM

    SteveB Guest

    "Ron Hunter" <> wrote in message
    news:...
    > MikeM wrote:
    >> I just bought some Duracel rechargable 2650 MAh NiMH batteries and a
    >> Duracell charger. The 2 Duracel chargers were 30min mn and 1 hr. Does
    >> this high speed charging shorten the life of batteries? Thanks
    >> Mike

    >
    > It might, but if the battery was made for fast charging, it is not likely
    > to damage it noticeably. Given the small cost of NIMH batteries, is it
    > really significant if fast charging reduces the life from 1000 charges to
    > only 500?


    More significant in usage is that fast chargers can't charge the batteries
    up as much as a slower one. The batteries may only reach 80-85% capacity
    with a 15 min charger, 95% with a 2hr charger.
     
    SteveB, Mar 9, 2007
    #11
  12. MikeM

    ASAAR Guest

    On Fri, 9 Mar 2007 15:05:38 -0000, SteveB wrote:

    > More significant in usage is that fast chargers can't charge the batteries
    > up as much as a slower one. The batteries may only reach 80-85% capacity
    > with a 15 min charger, 95% with a 2hr charger.


    Can't??? They usually don't stop completely, but throttle back to
    a slower charge rate after reaching 85% to 90% of full charge.
     
    ASAAR, Mar 9, 2007
    #12
  13. MikeM

    Guest

    Here's another thing I've wondered about: Is the shelf life of the
    charge the same?
     
    , Mar 9, 2007
    #13
  14. MikeM

    Ron Hunter Guest

    SteveB wrote:
    > "Ron Hunter" <> wrote in message
    > news:...
    >> MikeM wrote:
    >>> I just bought some Duracel rechargable 2650 MAh NiMH batteries and a
    >>> Duracell charger. The 2 Duracel chargers were 30min mn and 1 hr. Does
    >>> this high speed charging shorten the life of batteries? Thanks
    >>> Mike

    >> It might, but if the battery was made for fast charging, it is not likely
    >> to damage it noticeably. Given the small cost of NIMH batteries, is it
    >> really significant if fast charging reduces the life from 1000 charges to
    >> only 500?

    >
    > More significant in usage is that fast chargers can't charge the batteries
    > up as much as a slower one. The batteries may only reach 80-85% capacity
    > with a 15 min charger, 95% with a 2hr charger.
    >
    >

    That depends on the charger. Some are smart enough to charge at the
    maximum rate, then finish off with a lower charge rate, unless you take
    them out early (which is ok).
     
    Ron Hunter, Mar 10, 2007
    #14
  15. MikeM

    Ron Hunter Guest

    wrote:
    > Here's another thing I've wondered about: Is the shelf life of the
    > charge the same?
    >


    That would depend on the actual chemistry of the battery. Assuming that
    the ones made for rapid charging may have slightly different chemistry,
    as well as some provision for venting, they may also have different
    self-discharge rates. Has anyone actually tested this?
     
    Ron Hunter, Mar 10, 2007
    #15
  16. MikeM

    ASAAR Guest

    On Fri, 09 Mar 2007 20:37:24 -0600, Ron Hunter wrote:

    >> Here's another thing I've wondered about: Is the shelf life of the
    >> charge the same?

    >
    > That would depend on the actual chemistry of the battery. Assuming that
    > the ones made for rapid charging may have slightly different chemistry,
    > as well as some provision for venting, they may also have different
    > self-discharge rates. Has anyone actually tested this?


    Since the early days when NiMH AA cells had capacities of less
    than 1,000mAh, different brands had different self-discharge rates.
    The differences were considerable, probably because the first ones
    had very high self-discharge rates. Even though you don't use them,
    I'm surprised that you haven't recalled the NiMH cells that have
    extremely low self-discharge rates, Eneloops, Hybrids, et al. :)
     
    ASAAR, Mar 10, 2007
    #16
  17. MikeM

    Ron Hunter Guest

    ASAAR wrote:
    > On Fri, 09 Mar 2007 20:37:24 -0600, Ron Hunter wrote:
    >
    >>> Here's another thing I've wondered about: Is the shelf life of the
    >>> charge the same?

    >> That would depend on the actual chemistry of the battery. Assuming that
    >> the ones made for rapid charging may have slightly different chemistry,
    >> as well as some provision for venting, they may also have different
    >> self-discharge rates. Has anyone actually tested this?

    >
    > Since the early days when NiMH AA cells had capacities of less
    > than 1,000mAh, different brands had different self-discharge rates.
    > The differences were considerable, probably because the first ones
    > had very high self-discharge rates. Even though you don't use them,
    > I'm surprised that you haven't recalled the NiMH cells that have
    > extremely low self-discharge rates, Eneloops, Hybrids, et al. :)
    >


    I haven't used those yet. However, I expect that one would find some
    variation between various formulations from different manufacturers as
    well in them, but if I understand correctly, the new low self-discharge
    types aren't 'fast charge' capable.
     
    Ron Hunter, Mar 10, 2007
    #17
  18. MikeM

    ASAAR Guest

    On Sat, 10 Mar 2007 02:18:29 -0600, Ron Hunter wrote:

    > I haven't used those yet. However, I expect that one would find some
    > variation between various formulations from different manufacturers as
    > well in them, but if I understand correctly, the new low self-discharge
    > types aren't 'fast charge' capable.


    Where did you read that? I've seen manufacturer's claim that they
    are compatible with any charger designed for NiMH cells. The ones
    I've seen are Eneloops, Hybrids, RS's version and one sold in the
    U.K. (can't recall the brand name). The compatibility claim was
    most likely made by Sanyo and RayOVac, but I didn't take notes. :)

    In any case, I've not put them in any of my fast chargers, as the
    little Sony (3 or 4 hours) is quick enough and small enough to keep
    from getting in the way of other things, and some are in devices
    that have their own internal chargers. I'm sure that there are
    variations not just from brand to brand, but from different
    manufacturing runs within a brand. But the rates are so low that
    it's meaningless to me whether one brand would take 14 months to
    self discharge to the point than another would arrive at in 17.
     
    ASAAR, Mar 10, 2007
    #18
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