I've bought a USB wall charger to power my Raspberry Pi. I chose the 3A one so that I can connect some more power hungly devices like hard drives to the Pi's USB ports.
I can connect 2 cables to the charger I bought. I have two questions about it.

  1. the charger that came with my Android is 1,2 A I think. Is it potentially harmfull to my phone if I charge it with my new charger since it is 3 A?
  2. will I have a maximum of 3 A in total on the ports (so 2 * 1.5 for example), of will I have 3 A on each?

Q1: No it is not harmful. Your phone will only draw the current it needs from the charger. As long as the charger voltage is right and it is rated to supply at least the current required by the device you will be fine.

Q2: Without a data sheet we don't know.

Edit: The power delivery specifications indicate that 1.5 A was normal for battery charging with higher power available on later (2012) specifications. If it's a cheap PSU it might just have 5 V connected to each USB port without any current limiting at all, never mind individual port current limiting.

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  • \$\begingroup\$ It didn't come with any datasheet. So both are possible? Both types exist (3A in total or 3A shared)? \$\endgroup\$ – mgr326639 Dec 17 '15 at 22:22
  • \$\begingroup\$ See my update / edit. \$\endgroup\$ – Transistor Dec 17 '15 at 23:11

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