Credit: Twitter
Have you noticed that some chargers &/or cables take much longer to charge your phone? There are a number of reasons why this may happen, including the output of the charger & characteristics of the cable.
To identify slow cables & chargers, the quickest & easiest method is to measure the current, measured in Amps or milliAmps. A Google search for, “USB cable charger tester”, will yield a list of many devices which can measure the current flowing in a cable & charger combination. Many of them for less than $10.
Here’s a review of one which just makes it under the $10 bar
http://www.howtogeek.com/228869/how-to-monitor-your-usb-device-power-usage-and-output/
And a review of a few substantially more expensive meters which also measure a range of other parameters
http://the-gadgeteer.com/2016/11/26/qoopow-qualmeter-usb-cablecharger-testers-review/#more-207583
For Android devices, there are a number of apps which do the same thing. An advantage of this method is that it works for wireless charging too. Many have free versions. When tested side-by-side with an inexpensive physical meter similar to those mentioned in the tests above, all of the apps listed below yielded similar figures.
Ampere
from Braintrapp Tools
https://play.google.com/store/apps/details?id=com.gombosdev.ampere
Ampere Charging Meter
from ZAStudio Tools
https://play.google.com/store/apps/details?id=zastudio.com.ampere.charging.meter
Ampere Charging Meter Pro
from NovDev Tools
https://play.google.com/store/apps/details?id=com.livecharger / charging mobile device charge charger cable charging cable USB microUSB micro USB plug socket male female connector phone tablet charge recharge LiIon lithium ion battery charge rate Ampere Amp milliAmp MilliAmpere Volt Voltage /
