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Can I replace 10.8V battery with 11.1V battery?

Discussion in 'Laptops' started by frank, Aug 10, 2006.

  1. frank

    frank Guest

    I'm looking at an extra battery for my Dell Inspirion. My current battery
    is rated at 10.8V. I have a chance to get a really good price on another
    Dell battery made for 9400 that I know will fit, but it's rated at 11.1V.
    Is this enough of a diffence in voltage to cause any problems?
    frank, Aug 10, 2006
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  2. frank:

    Yes, the charging circuit will likely not work in the laptop. It will top
    off at 10.8 v. (Bad for the battery, bad for you.)
    Richard Johnson, Aug 10, 2006
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  3. How can that be?

    If the battery is rated 10.8v, it must be a Li-ion battery, consisting
    of 3 3.6 v cells in series (or 3 in series, coupled in parallel with
    another 3 in series. (3 x 3.6 = 10.8)

    I see no way to produce a 11.1 v battery, with any combination of
    either Li-ion cells (3.6, 7.2, 10.8, 14.4) or NiMH cells (1.25, 2.5,
    3.75, 5, 6.25, 7.5, 8.75, 10, 11.25, etc. If the battery is NiMH and
    his computer charging circuitry is for Li-ion, then I would think he'd
    have a LOT more problems than simply undercharging the battery.

    I would think that the type of battery would have more significance
    (as to whether there would be any problems).

    Charlie Hoffpauir
    Charlie Hoffpauir, Aug 10, 2006
  4. frank

    budgie Guest

    Assuming it is a proper fit, there should be no problems. These packs are both
    using Lithium types, three cells in series. The difference you see is in how
    the manufacturer of the battery pack rates the nominal voltage of the cells.
    Most use 3v6 as the nominal (4v2 max and around 3v0 at cutoff) while the odd few
    use 3v7.

    The charger should provide a controlled charge to the 12v6 termination point,
    although don't expect the laptop manufacturer to bother documenting this
    budgie, Aug 11, 2006
  5. frank

    M.I.5¾ Guest

    The 10.8 volt battery is a Lithium-Ion battery (3.6 volts nominal per cell).
    The 11.1 volt battery is a Lithium-Ion-Polymer (3.7 volts nominal per cell).
    The charging requirements of the two types of battery are sufficiently
    different that, unless the laptop is able to tell the difference and adjust
    the charge accordingly, the latter should not be used to replace the former.

    You should check with Dell whether your laptop is designed to work with the
    new battery. It is quite possible because the important charge circuitry
    may well be built into the battery.
    M.I.5¾, Aug 11, 2006
  6. frank

    M.I.5¾ Guest

    You clearly know absolutely nothing about lithium-ion batteries and
    therefore should refrain from offering advice. If the charge circuit
    'topped off' at 10.8 volts, you would end up with a battery that was only
    ~40% charged.
    M.I.5¾, Aug 11, 2006
  7. frank

    M.I.5¾ Guest

    How the manufacturer rates the cells has nothing to do with it. Lithium-ion
    batteries are far too unforgiving for people who nothing about them (as you
    appear not to do), to be giving advice on charging them. The differing cell
    votages arise, because the chemistry of the cells is different, and hence
    the charging requirements are also sufficiently different for the two types
    to be generally non interchangeable.
    M.I.5¾, Aug 11, 2006
  8. frank

    budgie Guest

    Izzat right?
    budgie, Aug 11, 2006
  9. Interesting... the Cadex web site, which I usually refer to with
    battery questions, lists the nominal cell voltage for Li-ion Polymer
    batteries as 3.6 v, the same as for Li-ion. What is it that makes the
    cell voltage different, as the chemistry seems so similar.

    Charlie Hoffpauir
    Charlie Hoffpauir, Aug 11, 2006
  10. I am going on his stated specification. If the battery is rated at 11.1
    vdc, and is placed into a charging circuit designed to charge it to 10.8
    vdc, the battery will never receive a full charge. That would be a bad
    thing for any battery, regardless of type. It will also be bad for the
    useful power for the person using the laptop as it will only work for a
    short time, or worse if the low voltage suspend circuitry takes the battery
    down to a level lower than specified for recharge, it can damage the
    battery. (Now, it is true that this will not be a problem if the charging
    circuit is built into the battery.)

    As to the person that says I know nothing about batteries and charging
    circuits. Prove it by trying it. Take a charger designed for a lower
    voltage battery and put it on a battery of a higher voltage. See if the
    results are satisfactory. (This goes for ANY battery.)
    Richard Johnson, Aug 11, 2006
  11. frank

    MegaMad Guest

    I have a Fujitsu Siemens Amilo M 1437.

    Bought it january 2005 with internal battery:
    - 10.8V 4400 mAh.
    Ordered spare march 2005 at Fujitsu Siemens site:
    - 11.1V 4400 mAh

    So now I seem to have a huge problem?!
    According to this topic it cannot work, will not charge, will fry
    loading circuit and more horror stories.

    As the 11.1V is the official FJS replacement for the 10.8V I think I am
    fairly safe.

    For those interested:
    10.8V part no 3S4400-F1P1-02
    11.1V part no 3S4400-S1S1-02

    As far as I'm concerned: the batteries are interchangable!

    Good luck!

    Leo - MegaMad
    MegaMad, Aug 11, 2006
  12. No, I'm not going to put a Li-ion battery in a charger that's not
    designed for Li-ion. since you haven't stated the technologies of
    either your original or the replacement, all I did was speculate on
    the charging. I'll leave it to you to try such dangeroug experiments.

    Charlie Hoffpauir
    Charlie Hoffpauir, Aug 11, 2006
  13. The OP stated his computer was a Dell, and did not state that the
    battery was a designated replacement. Certainly not the same situation
    you have.

    Charlie Hoffpauir
    Charlie Hoffpauir, Aug 11, 2006
  14. frank

    mike Guest

    Don't you just love the internet.
    Big discussion spoken with authority based on ASSUMPTIONS
    and CONJECTURE that may or may not bear ANY RELATIONSHIP AT ALL,
    to the actual situation.

    There's one fact evident: "We don't know enough about the situation
    to make ANY recommendations!"
    And a BAD recommendation can have DIRE consequences.
    And much of the "reasoning" supporting this conjecture is FAULTY.

    If you want a concrete example, here's one.
    Dell makes a 851UY battery. Plugs right in to any Dell C-series.
    IF you get out your magnifying glass, it "clearly" states,
    "Caution, not for use wit CP, CPi or CPiA."
    But that didn't stop the previous owner from blowing it up.

    If you wanna blow yourself up, fine. Don't help newbies blow themselves
    up with random assumptions. Responsible posters understand that years
    from now, someone is gonna google and find one faulty posting out of
    context...and do a bad thing based on it.

    91.3% of the advice you get off the internet is ill conceived. That's
    acceptable risk if it's a muffin recipe.
    It's not OK if it's battery charging advice.

    Call Dell and ask them!!!
    You can often get compatibility guidance from battery vendors by either
    contacting them of deciphering their website...but this info is not
    always 100% accurate.
    DO NOT take battery charging advice from a newsgroup.
    My apologies to the 8.7% of you who actually know what you're talking

    mike, Aug 13, 2006
  15. frank

    MegaMad Guest

    The OP states is is another <put brand name here> battery that will fit
    his <put brand name here> laptop.
    <Put brand name here> uses a different battery for almost every series
    of laptops they make.

    If you check the <put brand name here> website you will see that
    replacement batteries 451-10206 and 451-10207 differ only in capacity
    and that the 451-10206 is 11.1 V....

    Leo - MegaMad
    MegaMad, Aug 13, 2006
  16. frank

    M.I.5¾ Guest

    I work in the aerospace industry and probably know more about rechargeable
    battery technology than most people.
    M.I.5¾, Aug 14, 2006
  17. frank

    M.I.5¾ Guest

    This may be down to the way the manufacturer rates them. The voltage of
    both a lithium-ion and lithium-ion-polymer cell when fully charged is 4.2
    volts. Similarly both have a voltage of 3.0 volts when they are considered
    fully discharged (2.5 volts for some early types of the former). The
    difference is the shape of the charge/votage characteristic, the polymer
    type having a higher *average* voltage over the curve, hence the higher
    rated voltage from most sources.

    The polymer battery is based on an interesting type of polymer that was
    discovered entirely by accident when someone cocked up a perfectly normal
    polymerisation exercise*. The polymer is electrically conductive - or at
    least it is when heated to above ~60 ºC. If they could be made to work at
    normal temperatures, a true lithium-polymer battery would be almost entirely
    safe. Currently, the flammable electrolyte has to be added to make the
    lithium-ion-polymer battery. The presence of the polymer alters the
    mechanical and electrical characteristics somewhat from a straight

    *It has since been discovered that it can be doped and turned into a
    semiconductor and hence flexible circuits.
    M.I.5¾, Aug 14, 2006
  18. frank

    budgie Guest

    Ah, OK, citing your own cv. Cool.

    I have designed a commercially successful Li-Ion/Li-Polymer charger. And the
    charge regimes/settings for the two types are for all intents and purposes the
    budgie, Aug 14, 2006
  19. frank

    budgie Guest

    That is rather the same as I stated, and to which you seemed to feel obliged to
    take exception.
    budgie, Aug 14, 2006
  20. frank

    M.I.5¾ Guest

    Then you haven't designed your charger to give fully optimised charging
    times for the two types. We use mainly the polymer type for UAVs, under
    pretty well the limit of their operation. I can asure you that the charging
    requirements are very different when you want extremely short charge times
    (to 80% charged in under 10 minutes)
    M.I.5¾, Aug 14, 2006
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