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Micro-USB chargers: interchangeable?

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Micro-USB chargers: interchangeable?

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Old Jul 17, 2014 | 6:47 pm
  #1  
davie355
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Micro-USB chargers: interchangeable?
My new Chromebook charges over micro-USB, and I was hoping to carry only one charger for all of my devices.

I noticed the Chromebook is rated at 5.25V and 3A, whereas my generic charger is 5V and 2A. I'm fine with a slower rate of charging but is the voltage difference an issue?
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Old Jul 17, 2014 | 7:42 pm
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LtKernelPanic
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It'd probably work but I wouldn't do it personally. I've had to charge my iPad (12W draw)off my iPhone's 5w charger and that thing got *hot.* Charging the iPad while off helped a bit but it was still insanely hot.
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Old Jul 17, 2014 | 10:57 pm
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Loren Pechtel
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A charger with a higher power rating than the device should be ok. A charger with a lower rating is another matter--it should not be done.

The only time an over-powered charger would matter is if it doesn't have good voltage regulation and responds to a lower draw by producing more voltage.
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Old Jul 18, 2014 | 7:18 am
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gfunkdave
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Originally Posted by Loren Pechtel
A charger with a higher power rating than the device should be ok. A charger with a lower rating is another matter--it should not be done.
Actually, if a device wants more power than the charger can provide, they will "agree" on the charger just providing its maximum output. This is the USB spec - when you plug something into a charger, the device identifies what it's plugged into and determines how much power to draw.

The only time an over-powered charger would matter is if it doesn't have good voltage regulation and responds to a lower draw by producing more voltage.
In other words, a really badly designed charger. Avoid the $2 "Genuine Apple Chargers" and you will be fine.
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Old Jul 18, 2014 | 7:32 am
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mia
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Originally Posted by davie355
My new Chromebook charges over micro-USB,
I assume this is the HP Chromebook 11. In my experience it will draw only 0.5A from any charger other than the HP 3A charger. In other words, if you connect it to any charger which causes it to display the Low Power Charger warning, it will behave as if it is connected to a PC USB port. It won't matter if that charger is capable of supplying 1A, 2A, 2.4A or even 3A, it will only draw 0.5A, and it will charge very, very, slowly.
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Old Jul 19, 2014 | 2:37 am
  #6  
chx1975
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0.25V is within the tolerance of the USB standard: Max. voltage, 5.000.25 V (pre-3.0); 5.00+0.25-0.55 V (USB 3.0).
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Old Jul 19, 2014 | 8:10 am
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shenxing
 
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They probably upped the voltage to the high side of the USB spec to squeeze a little more power into the laptop charger.
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