Charging Adapter Volts, Amps, Watts

ptkelly

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Sep 28, 2013
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Ads for adapters sometimes mention volts, amps, or watts, sometimes two of the three and sometimes none. My Nexus 5x handles fast charging but what characteristic--volts, amps, watts--are important.
 

Mooncatt

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I don't know specifically what the Nexus 5X is designed for, so I'll limit this to more general info.

Voltage is the most important aspect, but all USB based chargers will output at least the required 5V standard and you should have no worries there. Modern chargers can have higher voltages, and they communicate with the device to make sure it can handle the higher voltage before scaling up. If the device isn't compatible, then the charger should revert to the traditional standard. As far as I'm aware, all reputable brands are fully backward compatible. Qualcomm had Quick Charge, either 2.0 or 3.0. I think Samsung brands there's as Adaptive Fast charging, or something similar. Simply being labeled as a rapid/fast charger or other genetic terms is likely a marketing gimmick and nothing more.

Amperage matters in that you want a charger that matches the output of the OEM charger. If it's too low, it won't be powerful enough to charge the device while it's in use. If it's higher than the OEM, that's perfectly fine. Amperage is "pulled" by the device, not forced by the charger. If the device is rated at 2A, you could have a 200A capable charger (Not that it actually exists) and it wouldn't over charge the device.

Wattage only really matters with multiple port chargers. With a single port charger, the rated voltage and amperage tells you everything you need. With a multi-port charger, things get a little more complicated. Going back to the basics, wattage is just volts X amps. A standard 5V 2A charger would therefore be rated 10 watts.

Now imagine a 4 port charger that uses standard voltage (5V) and has each port individually rated at 2A. That's theoretically a 40 watt power bank. Some cheaper brands may cut costs on the power supply and only have a total load rating of 20 watts. That means you could charge two devices at 2A, or four devices at 1A. If you connect enough devices to exceed the overall wattage of the bank, it will divide up the power between the active ports.

Higher quality power banks will give you full power availability through all ports at the same time.

TL;DR version: Don't concern yourself too much with all this. You can't buy a charger that's too strong because there are multiple protections to prevent this and everything is backwards compatible. About the worse that will happen if you get something too weak is it'll charge slower, and maybe wear out the charger quicker.
 

ptkelly

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Thank you. I don't need multiport chargers so I'll be looking for 5 volt, the standard, and 2 or more amps. The two I have are 3 amp and seem to work well with my Nexus 5x.