ITLT: USB Charging Speeds

USB chargers with USB cable

Ever had that moment where you plug your device in, see the charging symbol and thought that you were getting a good charge? Well I’ve had times when despite the charging icon showing, that the battery was actually getting slowly depleted, so here are some tips to make sure you’re charging optimally:

  • Check your charger
    • bigger devices usually require a charger that provides more amperage (tablets usually 2A, phones usually 1A)
  • Check your cables:
  • Check your USB port
    • for your computer / USB external battery packs with multiple USB ports: some ports could charge faster than others
    • find out how much power you’re getting via a device like the Practical Meter
  • Check your charging speed
    • Android
      • CurrentWidget (currently using this an available as a widget and/or on-going notification)
      • Charger Timer (haven’t used but looks good)
  • Force a faster charge
    • There seems to be a few Android apps that do this but it may also be device/kernel dependant. I have not tested these but there are apps like this

Other Notes

  • You can charge a device with a higher amperage charger: the amperage is the maximum rating that the charger can supply. If a device requests 1A then it will supply 1A even if the charger says 2A.
  • Voltage should be matched. 5V is the standard but I’ve seen slight variations of like 4.9V/5.2V but as it is only a small amount they shouldn’t be detrimental unless the device is very sensitive to it.
  • Also if you have chargers that specify power rating (e.g. Apple chargers), use the following formula:
    Power (W) = Current (A) x Voltage (V)

    So given a standard 5V

    • 12W charger will charge at 2.4A
    • 5W charger will charge at 1A.

2 thoughts on “ITLT: USB Charging Speeds

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