Forum Discussion
Gdetrailer
Jan 11, 2022Explorer III
wa8yxm wrote:
I think the USB "Standard" is 1/2 amp. and many are thus limited..
As you note. Many need 2, 3 or more Some devices will work with lower amps (Cell phones for example) but take longer to charge. (I use plug in adapters when I need speed)
Strictly speaking, USB charging was an afterthought and the original intention was to supply a very limited amount of power to devices on those ports for PCs like Keyboard/mouse and as USB became more universally used those current specs were widened.
In the strictest sense of PC USB ports, USB ports were limited to .5A (500Ma), the port then used a internal "hub" to give you multiple USB ports, that .5A was split between all of the hub outputs.
Fast forward a few yrs and newer USB specs allowed for standalone external USB chargers with .5A and then 1.5A and now 2.4A and even 3A all depending on the charger and the chip built into the device you are charging.
All the details you didn't know you wanted to know about USB charging specifications HERE
Generally, most external USB chargers fall into the .5A-2.1A category, some vendors mark the ports, some do not. So the reality is unless marked, assume the minimum of .5A and do a test charge. If the test charge is slower than what you normally see then you have a port that has a lower output. If it is just as quick as your normal charger then it is a higher output than .5A..
Note, it will not hurt your device to charge via a lower amp charger, it just takes a longer time to recharge.
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