offbrand chargers

Discussion in 'Droid 3 Accessories' started by darkmatter, Jul 17, 2011.

  1. darkmatter

    darkmatter Member

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    So, I've just noticed a little something regarding chargers and the D3.

    I usually use my kindle charger, since it fits and is convenient. However, I unplugged the phone and saw that battery was at 60%. hmmm.

    So, I took the usb cable, and plugged it into my nook color charger, and it charged up just fine.

    output of kindle plug. 4.9V / 0.85A

    output of nook color plug 5.0V / 1.9A

    and stock motorola plug 5.1V / 850mA (yea, I don't feel like converting that, though I'd venture a quick guess at 0.85A)

    So, not sure exactly what all that means, but there you go, lol. the kindle plug didn't charge the battery at all, but the nook color one did.
     
  2. TyrantII

    TyrantII Member

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    Yikes. First of, stop plugging in a $450 device into things you don't know about. You apt to fry your new toys.

    A= Amps / mA = MilliAmps ..... 1A = 1000mA. The voltage is what it says it is.

    I wouldn't recommend pluging it into anything more then 1A/1000mA. You can seriously ruin the phone / battery. I did read somewhere that the phone only will pull it's max, but I'm not sure if a compatible charger able to push that exact amount is needed.

    Most stock wall charges for the Droid series have around 600-750mA's at 5V. You can safely go up to 1000mA's, but some do think it will lessen the life / charge of the battery. I use a 12V to 5V 1000mA converter in my car.
     
  3. darkmatter

    darkmatter Member

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    That was pretty much the point. Most ppl will see that the plugs all fit. You have a wall plug with a usb port, it should work, right? Not necessarily. I wanted to pass along that we should look at things, cause not all wall plugs with usb ports are equal.

    Would you pretty much call someone an idiot for buying a usb wall plug from walmart that says its for phones and other devices?

    Sent from my DROID3 using Tapatalk
     
  4. TyrantII

    TyrantII Member

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    Nope, just mislead. Not everyone is tech savvy, nor should we expect them to be. But people should know the rule of thumb not to just "expect" something with electronics. It's a great way to get a $500 paper weight

    :)

    Personally, I'm worried about the weird changes they've made to the car dock. A normal USB cable better work with it.
     
  5. b00mb00mchuck

    b00mb00mchuck Member

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    Never take a Motorola charger for granted... its not just the voltage and amperage... its the way that converter cleans up the a/c power when it's converted to d/c... Droid 1 had all kinds of problems with the capacative touch screen when charged with a cheap charger... be careful and read the first couple pages of your user guide... motorola is very clear about how to use their devices properly...

    Somebody above said that motorola devices usually come a charger between 600 and 750... I find this a little low... every motorola charger I have is at 850mA (.85A)...
    that charger you have at 1.9 will kill your charge circuit in your phone eventually
     
  6. TyrantII

    TyrantII Member

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    Doh, you're right. Most Moto chargers are 850. Most store bought third party are 600-750. 1000 can be used, but might shorten battery life. Anything more and people seem split if it'll eventually fry the charging circuit that limits what it draws, or if it'll just shorten battery life faster.
     
  7. tonydelite

    tonydelite Member

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    The charger that came with the Droid3 dock is only 750mAh.
     
  8. drysdan

    drysdan New Member

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    My understanding of the charging circuitry is minimal, but most of these comments go against everything I know about electricity. I don't think a charger can 'push' extra amps at a phone. The amperage rating is the amount of current the charging converter is capable of providing to the device, not how much it's always putting out.

    I'd be more worried that the Motorola chargers are putting out 5.1 volts on a standard (USB) that is designed for 5 volts. The voltage supplied by the charger is constant, or 'pushed' as a commenter above stated. It shouldn't change, but the amperage being drawn by the device is dependent on what the device is.

    I'm pretty sure the amperage rating on the charger block is to indicate that you shouldn't plug in something that requires more than that, or you can overload the transformer in the charger.


    That said, I know we're dealing with some intricate circuitry in these devices, so there may be call to be careful about what you use to charge your phone, but the fact that you can charge it off the usb port of your computer, and no one seems to caution against that, seems to indicate that most converters that use good circuitry should be ok? Maybe? (as one commenter above mentioned, the charging converter is 'cleaning up' the power from the wall. Not sure what that means, but there is more to it than just AC to DC conversion)...
     
  9. kilowatt

    kilowatt New Member

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    Drysdan you are correct.

    As long as the voltage is correct your phone will only draw the current it needs to charge itself. You can hook it up to a charger capable of feeding it 500 amps but the phone will only draw what it needs. If the voltage of the charger is wrong you may damage the device.

    The current rating of a charger is the max current that it can produce while still maintaining the proper output voltage. If you connect the phone to a charger that doesn't provide enough current, the voltage will drop because the phone will try to draw more current than the charger can produce and still maintain the proper voltage.

    For any device you need a charger that produces the proper voltage and also can produce at least enough current for what the device requires.
     
    Last edited: Jul 18, 2011
  10. drysdan

    drysdan New Member

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    Thanks for confirming that.

    The only thing that seems odd about my D3's charger is that it says it puts out 5.1 volts, when all my other usb based chargers (nook, Nexus One) say they put out 5 volts even, which is what the usb standard calls for.

    Also, usb ports on computers put out 5 volts even, and I haven't heard anyone say bad things about charging their phone from a usb port.

    Not sure what to make of this yet, though.... Maybe somebody with a more extensive knowledge of electronic engineering can shed some light.
     
  11. kilowatt

    kilowatt New Member

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    Most devices these days are fairly tolerant of the supply voltage just by the nature of the charging circuits used. Even older devices would usually be speced for a particular supply voltage +/- 10%. 5.1V is 5V + 2% so.. close enough. As the voltage goes up the current goes down to supply the same wattage. The phone might charge slightly faster with the slightly higher voltage.

    It's possible they use the higher voltage to detect that the charging device is a wall supply verses a USB port and adjust the charging circuit to draw more current and do a faster charge. Although I think there isn't quite enough voltage difference in this case to detect that reliably.
     
  12. geojock

    geojock New Member

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    I am upgrading from original droid to Droid 3. Will my Droid 1 charger work?
     
  13. geobernd

    geobernd New Member

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    Yes. So the upgrade will give you an 'extra' charger...

    Sent from my DROID3 using DroidForums
     
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0.85a stronger than 1000ma?

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using kindle charger for droid
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