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5.0V Charger?

  • ozOzo Top 10 Forum Poster Monday, January 09, 2017 4:04 AM Reply

    @gasbag11

    Since you're the one who made me buy these lights even though I don't want them, I've been meaning to ask you, can they be charged with an ordinary cellphone wall charger?... One that has a Micro USB I mean, like most Androids do. What mystifies me a bit is that if they are made to be charged from a USB port on a computer for instance, they will be drinking in 5.0V x about 1.0A, the same as a wall-wart, and that seems a kind of in-between voltage for a Lithium battery... too much for a single 3.8V and not enough for a 2 in series 7.6V?

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  • gasbag11 Top 10 Forum Poster Monday, January 09, 2017 5:56 AM Reply

    My son and brother-in-law both use wall warts to charge the ones I gave them. 


    I used  my computer and occasionally a wall wart to charge mine until it was taken and I was told: "You shop online all the time... buy yourself another one." lol


    They must have circuitry in them to lower the 5V down to 4.2, (or whatever upper limit is used) and they will only draw the current (amps) they need. 


    I'm sure @sheepish or @desolder will correct me if I'm wrong. 


    edit - typo

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    post edited by gasbag11 on 1/9/2017 at 6:11 AM
  • sheepish Top 10 Forum Poster Monday, January 09, 2017 6:29 AM Reply

    They must have circuitry in them to lower the 5V down to 4.2, (or
    whatever upper limit is used) and they will only draw the current (amps)
    they need.


    I think desolder mentioned a few months ago that cellphones just use a resistor to drop that extra voltage - it's the simplest and smallest way of doing it. And they'd have something to stop the charging when the battery got to 4.2 V.

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  • gasbag11 Top 10 Forum Poster Monday, January 09, 2017 6:40 AM Reply

    Another possibility occured to me. 


    I'm no electronics expert, but since everything I've seen/read about USB rechargeable devices of whatever type, and they all seem to have standard Li-ion cells (3.7V nominal, 4.2V max) maybe the 5V rating for the chargers is a misnomer and they actually only output 4.2V max? 


    edit - Didn't see sheepish's post before I proved I'm no electronics expert. lol



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    post edited by gasbag11 on 1/9/2017 at 6:48 AM
  • ozOzo Top 10 Forum Poster Monday, January 09, 2017 7:02 AM Reply

    Thanks guys. I haven't even got them yet but I was concerned that 5V may shorten their lifespan.


    GB, I will no longer refer to you as that Flashlight Nutter, especially after you prefaced your reply with "My son...", you will now be known as "The Enlightened One"

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  • sheepish Top 10 Forum Poster Monday, January 09, 2017 7:28 AM Reply

    Just to confuse you even more, gasbag11, the latest cellphone I bought (basically to use as a very inexpensive GPS unit) uses a 4.35 V battery.


    you will now be known as "The Enlightened One"


    That's a bright idea.

    DX has found a new way to deceive customers:
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    http://club.dx.com/forums/forums.dx/threadid.1462252
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  • gasbag11 Top 10 Forum Poster Monday, January 09, 2017 10:29 AM Reply

    LOL 


    My monster light (3800 lm) should be here in a few days, so some of my neighbors will be getting "enlightened" briefly when I test it out. :)

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  • ozOzo Top 10 Forum Poster Monday, January 09, 2017 11:16 AM Reply


    http://i.imgur.com/4GmSDZR.png
    img src:
    http://i.imgur.com/4GmSDZR.png


    I can just picture it. O'Hare Airport temporarily closed until they find out where all that light is coming from!

    Worldwide 4G bands list:
    http://en.wikipedia.org/
    wiki/List_of_LTE_networks
    Worldwide 3G bands list:
    https://en.wikipedia.org/
    wiki/List_of_UMTS_networks
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    post edited by ozOzo on 1/9/2017 at 12:22 PM
  • matrix-neo Moderator Monday, January 09, 2017 11:19 AM Reply

    there's more than 'just a resistor' in Lithium based devices(hopefully!), in the good old days yes dumb chargers for Ni-Cd used power resistors and you were the 'smart' in 'smart charger' so you had to unplug it, although Ni-Cd was waaay more forgiving at overcharging, with LiOn and LiPo you need a combination of constant current and constant voltage for safe and proper charging

    @ozozo, yes the charging circuit takes 5V but since no circuit/battery is 100% efficient not all that is going to battery, the charging circuit consumes a little power itself, I thought about buying this but although it's neat, for the price of one of these you can almost buy three of sku.453518, don't need multi mode for a keyring light

    Resistance is futile-give in to DX gadget craving!
    also a voluntary mod-be nice please!
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  • ozOzo Top 10 Forum Poster Monday, January 09, 2017 1:40 PM Reply

    I have to agree Matrix, that $10 is too much for a keyring light. The Ultrafire looks cute too but it's not really fair to compare them just on price. From what I've heard the Nitecore is really built to last. It's actually smaller than the Ultrafire and only about half the weight. The male usb would be handy on the Ultrafire I guess but I find the 80lm a bit hard to swallow, whereas the 45lm claimed by nitecore is apparently close to the money from all reports.

    PS. If you think $10 is too steep, look up 'nitecore tip 360' on the net. DX don't have them.

    Worldwide 4G bands list:
    http://en.wikipedia.org/
    wiki/List_of_LTE_networks
    Worldwide 3G bands list:
    https://en.wikipedia.org/
    wiki/List_of_UMTS_networks
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