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A Simpler Solar Charger Question (I hope)

Discussion in 'General Electronics Discussion' started by Bumblebee001, Jul 29, 2013.

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  1. Bumblebee001

    Bumblebee001

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    Jul 19, 2013
    Hi,

    I just bought a solar charger for my mobile phone. I discovered that instead of charging my phone battery, the charger drained the remaining power in the battery!

    I must point out that the cable that came with the device was defective. I repaired the cable and I am reasonable sure I did not cross the wires over.

    My question is: would adding a diode in series with the one of the output leads ensure that the current will flow towards the phone battery not vice-versa? If yes, is there a specific diode I should use? Any advice on the matter will be appreciated.

    Mark

    PS: The output voltage of the solar charger is 5.5V
     
  2. davenn

    davenn Moderator

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    Sep 5, 2009
    have you got any info on the solar charger?
    a link to the site where they are being sold ?

    or at the very least some sharp and well lit pics of the charger and the "repairs" you made

    without more detailed info, it would be difficult to help you
     
  3. Bumblebee001

    Bumblebee001

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    Jul 19, 2013
  4. Bumblebee001

    Bumblebee001

    55
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    Jul 19, 2013
    The issue remains:

    How can I ensure that the charger charges the mobile phone battery not the other way round (ending up with a completely drained phone battery, defeating what the charger was fundamentally meant to do)?

    Mark:confused:
     
  5. (*steve*)

    (*steve*) ¡sǝpodᴉʇuɐ ǝɥʇ ɹɐǝɥd Moderator

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    You could place a schottky diode in series with the output.

    It would be better to place this inside the case.

    This will reduce the output voltage slightly.
     
  6. Bumblebee001

    Bumblebee001

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    Jul 19, 2013
    Would this be the same as the diodes used with LEDs? I have some of these.
     
  7. (*steve*)

    (*steve*) ¡sǝpodᴉʇuɐ ǝɥʇ ɹɐǝɥd Moderator

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    I'm not sure what diodes you're talking about. Normally resistors are used with LEDs.

    Schottky diodes are special diodes with a low forward voltage drop.
     
  8. Bumblebee001

    Bumblebee001

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    Jul 19, 2013
    Oops! You are absolutely right. What a gaff! Sorry!

    The diodes I have are 1N4148.Would one of these be ok?

    Mark
     
  9. davenn

    davenn Moderator

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    Sep 5, 2009
    no they are very low current capability and not Schottky diodes they will burn out
    their voltage drop would be considerably higher

    Dave
     
  10. (*steve*)

    (*steve*) ¡sǝpodᴉʇuɐ ǝɥʇ ɹɐǝɥd Moderator

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    1N4148 are a low current silicon diode.

    As a test you could try a 1N4001 or 1N400x or 1N540x. (where x is any number).

    You'll probably be looking at a black epoxy device rather than a glass bead.
     
  11. Bumblebee001

    Bumblebee001

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    Jul 19, 2013
    I am a complete idiot in electronic stuff so please bear with me....

    How about an actual LED which would also serve as an indicator that the battery is charging? I have loads of these - different colours and voltages (and resistors of various ohm values).
     
  12. Bumblebee001

    Bumblebee001

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    Jul 19, 2013
    If an LED is not appropriate, would a 1N4007 1A 1000V rectifier diode be what I should use?
     
  13. (*steve*)

    (*steve*) ¡sǝpodᴉʇuɐ ǝɥʇ ɹɐǝɥd Moderator

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    If you want to prevent the phone discharging back into the battery, then a 1N4007 could be used as a test, but it would be inefficient and might drop too much voltage for the phone to handle. But you could give it a try.
     
  14. Bumblebee001

    Bumblebee001

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    Jul 19, 2013
    I cannot perform such test as I have no such diodes.

    I would have thought there would be some standard solution to such an issue... ie having two batteries attached to each other, one of which being the reservoir of energy from solar panel/s. How else could one ensure that the correct battery delivers the charge to another and not the reverse?
     
  15. (*steve*)

    (*steve*) ¡sǝpodᴉʇuɐ ǝɥʇ ɹɐǝɥd Moderator

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    How many times have I said that a diode is what does that?

    You ask if a 1N4007 could be used. I suggest that it could be used (at least as a test) and then you complain that you don't have one.

    What do you want me to do?
     
  16. Bumblebee001

    Bumblebee001

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    Jul 19, 2013
    Sorry to be such a cause for irritation. That was never intended.

    My concerns stemmed from the fact that:
    1. diodes apparently have different amperage and voltage values. I have no idea what the implications of these would be eg whether a 1A 1000V diode would be as good as any other with different specifications
    2. I was disappointed to find that the only diodes I have as a hobbyist are LEDs. They are diodes too.... at least in name....
    3. It hardly makes any sense to buy components merely to test them out. Should they not serve the intended purpose adequately, how many components would I have to buy to achieve the ultimate goal, if this is achievable? Then I would probably be spending more money on components to make up for the "defect" of a gadget than the cost of the gadget itself.

    No intention of being argumentative. Just trying to explain the reason underlying my questions.

    Apologies once again.

    Best wishes to all on this forum

    Mark

    PS I conclude that you live closer to Beijing than the ice shelf :-D
     
    Last edited: Aug 2, 2013
  17. BobK

    BobK

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    Jan 5, 2010
    Then just buy some shottky diodes as originally suggested.

    Bob
     
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