MOBILE PHONE CHARGING

Discussion in 'General Electronics Chat' started by b.shahvir, Feb 9, 2009.

  1. b.shahvir

    Thread Starter Active Member

    Jan 6, 2009
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    Hi Guys, :)

    My mobile phone battery was completely drained and so I put it up for charging. However, inspite of the charger providing charging current to the cell phone, the phone shut down several times indicating ‘Battery Low’.

    As per my understanding, the charger charges up the cell phone battery and also provides electrical power to the cell phone circuitry in parallel. So, I fail to understand as to why the phone shut down inspite of the charger supplying electrical power to the phone circuit ?

    Also, if the cell phone did shut down, it would mean that the drained battery was still supplying or attempting to supply electrical power to the phone’s electronic circuit inspite of the charger being perfectly connected. (this was verified as the phone display indicated that battery charging was in progress).

    So, my query is; How can the battery charge itself and at the same time manage to supply electrical power to the mobile phone circuitry ? How can a battery charge as well as discharge at the same time ? Can someone please provide me with a suitable explanation for this phenomenon as it completely goes against the laws of electrical physics! I would be very grateful.

    Thanks & Regards,
    Shahvir
     
  2. b.shahvir

    Thread Starter Active Member

    Jan 6, 2009
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    Someone please reply!

    Kind Regards,
    Shahvir
     
  3. DumboFixer

    Active Member

    Feb 10, 2009
    219
    34
    The battery isn't charging and discharging at the same time. The charging current is being split between the charging circuit and the phone itself to show the charging symbology and to monitor the charge sequence.
     
  4. b.shahvir

    Thread Starter Active Member

    Jan 6, 2009
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    :) Thanks. I understand, but if thats the case, why did the phone shut down several times inspite of the charger providing direct electrical power to its electronic circuit, in parallel with the charging battery?

    The charger should have made the phone independant of the battery (which is in charging mode) and not cause it to shut down on 'Battery Low'. It would mean that the cell phone is still dependant on the drained battery for its electrical power requirements! Please comment.

    Kind Regards,
    Shahvir
     
  5. triggernum5

    Active Member

    May 4, 2008
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    I think the power from the phone would come from the battery, not the charger.. The charger feeds the battery dirty power, the battery provides clean power.. Can you power the phone if its attached to the charger, but with the battery removed?
    Also, cell chargers usually aren't chargers per se, they're simply adapters that feed power to the charging circuit in the phone..
    And if a battery is drained completely, then its pretty much dead.. You need a minimum amount of charge in it to recharge it..
     
  6. Barry M

    Active Member

    Feb 11, 2009
    35
    0
    A mains charger always supplies constant power and when a phone is plugged in immediately begins charging until the phone itself stops the charge.

    A USB charge has to be requested unless you mod a cable for a constant supply. The phone has to have enough power to talk to the computer and make the request.

    Thats my understanding of it anyway seeings as Ive never had a completely battery dead phone recharge via USB.
     
  7. b.shahvir

    Thread Starter Active Member

    Jan 6, 2009
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    :( I did not quite grasp the concept of 'clean power' and 'dirty power'. As per my understanding electrical power is the flow of electrons.

    The battery cannot take as well as give electrons at the same time! i.e. it cannot charge and discharge at the same time. If the charger provides power to the phone circuit in parallel with the battery, then the phone should not shut down, as the charger supplies independent electrical power to the cell phone circuit.

    Kind Regards,
    Shahvir
     
  8. Barry M

    Active Member

    Feb 11, 2009
    35
    0

    D'oh, wrong thread ... possibly wrong forum too ...
     
  9. Von

    Active Member

    Oct 29, 2008
    65
    0
    The AC adapter is not capable of supplying the current required to run the phone. It is a battery charger NOT eliminator!
     
  10. b.shahvir

    Thread Starter Active Member

    Jan 6, 2009
    444
    0
    :) So, what is the mechanism of charging, technically! and why did the phone shut down during charging?

    Kind Regards,
    Shahvir
     
  11. beenthere

    Retired Moderator

    Apr 20, 2004
    15,815
    282
    Your charger may simply not be able to supply charging current and have enough capacity to operate the phone at the same time.

    Remember that we have no idea of what mobile phone you have of the output of the charger. It is quite likely that the manual for the phone would have information as to the capacity of the charger.
     
  12. Von

    Active Member

    Oct 29, 2008
    65
    0
    Mr. b.shahvir,

    You sound skeptical of the information provided to you thus far as you seem to challenge just about every response. This is different from seeking clarification.

    There is plenty of material available on the charging algorithms of Lithium and other battery chemistries on the WWW.

    As beenthere has implied there are hundreds of variables and possible causes. If your battery is damaged by age or abuse (over discharge) it may never fully or adequately recharge again. Thus the phone is not able to properly reboot and register with the network.

    Try calling customer service/assistance for the particular brand of phone you are having problems with.
     
  13. b.shahvir

    Thread Starter Active Member

    Jan 6, 2009
    444
    0
    :) Sorry! my intention was not challenge any of the posts. I greatly appreciate the help you guys are providing.

    You might have misunderstood my query. I am concentrating more so on the physics of battery charging process.

    Let me clarify again;

    Charger is connected to phone charging the almost dead battery___ I start up the phone but it shuts down several times indicating 'Battery Low'___ this means that the weak battery is attempting to supply electrical power to the cell phone circuitry___ but as i have mentioned earlier, the battery is still in charging mode___ so , how can a battery charge itself and at the same time supply current (discharge) to the phone circuitry?___ There has to be an external electrical source supplying power to the cell phone circuit (in parallel) while the battery is charging up!
    This is what is confusing me.

    FYI-- My battery is charging up normally and cell phone working OK.

    Kind Regards,
    Shahvir
     
    Last edited: Feb 14, 2009
  14. MareBear

    Member

    Oct 29, 2008
    22
    0
    from my understanding of chargers and batteries is that the charger is converted from AC voltage to DC voltage. Your cell phone can only accept DC voltage so your phone is using purely DC while your charger is converting AC -> DC. What im trying to say is that since the charger has to convert first before feeding the battery dc voltage, the phone is using the dc voltage faster than the charger can provide. Thus this causes the phone to die if it is almost dead or completely dead, that is why you have to have it off with the charger connected for at least 10-20 minutes before you can turn on your phone without it dying.
     
  15. b.shahvir

    Thread Starter Active Member

    Jan 6, 2009
    444
    0
    ;) No offense, but i don't think this logic is technically correct!
     
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