Guide: how to test USB power source and USB cable without any special hardware.

All you need is any iOS or Android device (phone, tablet, etc.).
Install one of these free apps: Battery Life (for iOS) or Current Monitor (for Android).

Now when you plug in your device to charge, you can monitor charging current, just like you would with a special “USB Current detector” device:

If you’ve never done this before, go over all your numerous USB cables one after another plugging them into the same (preferably high quality) power supply and watch the current draw. You will be surprised how many cables you will decide to throw away after this simple test. Hopefully, you will also find some cables to order more of.

Update: if Current Monitor does not work on your Android device, try Ampere instead:

I’ve been using Ampere for my android phone and so far it’s been great. It has definitely between a great help in weeding out my bad cables and even chargers. So far the best can’t has been the one that came with my anker car charger! I’ve been registering over 2A with that cable on my turbo charger.

Current monitor didn’t work on my lenovo k3 note, but ampere seems to be perfectly working, thank you guys !

Thanks, very nice.

Nice post. Thanks for sharing. :laughing:

Yeah same here.

Current Monitor didn’t work on Motorola E phone, nor on Hudl 2 tablet.

Used this today, because some of my cables are slow as hell with charging.

The current was the same on all (Phone is limiting it to 1.5Amps) - but the voltage dropped on the suspicious one (5.077 on an Amazon Basic Cable, 4.6xx on a “Original” Xiaomi Cable from BangGood)

Blitzwolf, Amazon and the Xiaomi-Cable that came with my Redmi Note 2 are the best ones I have.

These applications are useful to get an idea about what is going on, but their measurement are not measuring how much current goes into the phones usb port (They may measure current into the battery correctly, I have not checked that).

Here are two measurements with a usb meter and Ampere: