1. vaderag's Avatar
    Short version: what is the best way to charge a newer device from a USB port that only outputs 0.5a?

    Long version:
    Been out today in my new car and tried charging my phone from the built in usb... didn't do anything. Makes the charging noise on the phone but no charge.

    Obviously I'm guessing it must be only outputting at 0.5a which is very low for today's devices... what can I do? Is there any way to bump up a 0.5a to higher easily (appreciate this might vary by a billion factors, but guess the USB is coming off the car's 12v rails somewhere along the line...)

    Another thought that came to me was putting a battery pack that charges slower in the middle, but i don't know if this will work given that i'll probably be drawing more than i'll be getting in to it... and can they even charge as they are outputting?

    Any thoughts welcome!!
    Cheers

    Xperia Z5 on Marshmallow
    04-23-2016 04:12 PM
  2. sfoLAX's Avatar
    Hello. That's very low. Possibly only meant for media input. If you have an older cigarette / power point a single or double port 2.1A usb adapter are now cheaply available.
    04-23-2016 04:44 PM
  3. vaderag's Avatar
    Unfortunately the only one is in quite an awkward position for the gearstick... Ideally I'd like to find a way to use the USB that's out the way, but that is my fallback....
    04-23-2016 04:49 PM
  4. sfoLAX's Avatar
    I can't help too much technically.
    Site ambassador Rukbat may be able to advise better in this thread
    [Guide] The Care and Feeding of Lithium Polymer Batteries
    or he may catch this later.

    What I have picked up from the forums is devices govern their own rate of charge from a supply, though also determined by the level of the battery.
    Yikes
    Try it this way - at around 50% the battery is easier to charge and generates less heat than near empty or full.
    A 2.1A source could be supplying a rate of well below 1A at either extreme, and probably between 1.8 A to 2.2A max between 30 - 80% very roughly.
    I'm winging it now

    If you try the GSam battery app and fully charge and maybe deplete from 100 % to a low percentage a few times to calibrate it, it should show the rate of charge at different battery percentages.

    The car usb port may be a 1A source, and my 1A car charger has served me well with several phones though I now use a 2.1A.

    There may be other factors affecting the usb port and drain.

    Any spec from the car manufacturer or audio supplier. There should be info somewhere.
    I wouldn't think you could up a 0.5A source, but don't know for sure.
    04-23-2016 05:43 PM
  5. vaderag's Avatar
    I can't seem to find the spec, but given that I have a cheap car adaptor that is rated it 0.5 and I have a 1 charger here which gives enough to charge, im pretty certain it's 0.5
    04-24-2016 01:56 AM
  6. sfoLAX's Avatar
    I can't seem to find the spec, but given that I have a cheap car adaptor that is rated it 0.5 and I have a 1 charger here which gives enough to charge, im pretty certain it's 0.5
    It's a lottery who answers a thread in this quick fire Any Questions forum. It get's inundated, but encourages new members.

    Try the Android Automotive section, or General Help and How To in the Android Central Lounge (or the battery Guide thread above).
    vaderag likes this.
    04-24-2016 05:49 AM

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